Ubuntu Manpage: scons - a software construction tool

NAME

       scons - a software construction tool

SYNOPSIS

       scons [options...] [name=val...] [targets...]

DESCRIPTION

scons orchestrates the construction of software (and other tangible products such as
documentation files) by determining which component pieces must be built or rebuilt and
invoking the necessary commands to build them.

You instruct scons by writing a configuration file which specifies the files to be built
(targets), and, if necessary, the rules to build those files. Premade rules exist for
building many common software components such as executable programs, object files,
libraries, so that for many software projects, only the target and input files need be
specified.

When invoked, scons searches for a file named SConstruct (it also checks alternate
spellings Sconstruct, sconstruct, SConstruct.py Sconstruct.py and sconstruct.py in that
order) in the current directory and reads its configuration from that file. An alternate
file name may be specified via the -f option. The SConstruct file can specify subsidiary
configuration files by calling the SConscript function. By convention, these subsidiary
files are named SConscript, although any name may be used. As a result of this naming
convention, the term SConscript files is often used to refer generically to the complete
set of configuration files for a project (including the SConstruct file), regardless of
the actual file names or number of such files.

Before reading the SConscript files, scons looks for a directory named site_scons in
various system directories and in the directory containing the SConstruct file and
prepends the ones it finds to the Python module search path (sys.path), thus allowing
modules in such directories to be imported in the normal Python way in SConscript files.
For each found site directory, if it contains a file site_init.py it is evaluated, and if
it contains a directory site_tools the path to it is prepended to the default toolpath.
See the --site-dir and --no-site-dir options for details on default paths and controlling
the site directories.

scons configuration files are written in the Python programming language, although it is
normally not necessary to be a Python programmer to use scons effectively. Standard Python
scripting capabilities such as flow control, data manipulation, and imported Python
libraries are available to use to handle complicated build situations.

scons reads and executes all of the SConscript files before it begins building any
targets. To make this clear, scons prints the following messages about what it is doing:

$ scons foo.out
scons: Reading SConscript files ...
scons: done reading SConscript files.
scons: Building targets ...
cp foo.in foo.out
scons: done building targets.
$

The status messages (lines beginning with the scons: tag) may be suppressed using the -Q
option.

scons does not automatically propagate the external environment used to execute scons to
the commands used to build target files. This is so that builds will be guaranteed
repeatable regardless of the environment variables set at the time scons is invoked. This
also means that if the compiler or other commands that you want to use to build your
target files are not in standard system locations, scons will not find them unless you
explicitly include the locations into the value of PATH in the ENV variable in the
internal construction environment. Whenever you create a construction environment, you can
propagate the value of PATH from your external environment as follows:

import os
env = Environment(ENV={'PATH': os.environ['PATH']})

Similarly, if the commands use specific external environment variables that scons does not
recognize, they can be propagated into the internal environment:

import os
env = Environment(ENV={'PATH': os.environ['PATH'],
'ANDROID_HOME': os.environ['ANDROID_HOME'],
'ANDROID_NDK_HOME': os.environ['ANDROID_NDK_HOME']})

Or you may explicitly propagate the invoking user's complete external environment:

import os
env = Environment(ENV=os.environ)

This comes at the expense of making your build dependent on the user's environment being
set correctly, but it may be more convenient for many configurations. It should not cause
problems if done in a build setup which tightly controls how the environment is set up
before invoking scons, as in many continuous integration setups.

scons can scan known input files automatically for dependency information (for example,
#include preprocessor directives in C or C++ files) and will rebuild dependent files
appropriately whenever any "included" input file changes. scons supports the ability to
define new scanners for unknown input file types.

scons is normally executed in a top-level directory containing an SConstruct file. When
scons is invoked, the command line (including the contents of the SCONSFLAGS environment
variable, if set) is processed. Command-line options (see the section called “OPTIONS”)
are consumed. Any variable argument assignments are collected, and remaining arguments are
taken as the targets to build.

Values of variables to be passed to the SConscript files may be specified on the command
line:

scons debug=1

These variables are available through the ARGUMENTS dictionary, and can be used in the
SConscript files to modify the build in any way:

if ARGUMENTS.get('debug', 0):
env = Environment(CCFLAGS='-g')
else:
env = Environment()

The command-line variable arguments are also available in the ARGLIST list, indexed by
their order on the command line. This allows you to process them in order rather than by
name, if necessary. Each ARGLIST entry is a tuple containing (argname, argvalue).

Targets on the command line may be files, directories, or phony targets defined using the
Alias function. The command line targets are made available in the COMMAND_LINE_TARGETS
list.

If no targets are specified on the command line, scons will build the default targets. The
default targets are those specified in the SConscript files via calls to the Default
function; if none, the default targets are those target files in or below the current
directory. Targets specified via the Default function are available in the DEFAULT_TARGETS
list.

To ignore the default targets specified through calls to Default and instead build all
target files in or below the current directory specify the current directory (.) as a
command-line target:

scons .

To build all target files, including any files outside of the current directory, supply a
command-line target of the root directory (on POSIX systems):

scons /

or the path name(s) of the volume(s) in which all the targets should be built (on Windows
systems):

scons C:\ D:\

A subset of a hierarchical tree may be built by remaining at the top-level directory
(where the SConstruct file lives) and specifying the subdirectory as the target to build:

scons src/subdir

or by changing directory and invoking scons with the -u option, which traverses up the
directory hierarchy until it finds the SConstruct file, and then builds targets relatively
to the current subdirectory (see also the related -D and -U options):

cd src/subdir
scons -u .

In all cases, more files may be built than are requested, as scons needs to make sure any
dependent files are built.

Specifying "cleanup" targets in SConscript files is not usually necessary. The -c flag
removes all files necessary to build the specified target:

scons -c .

to remove all target files in or under the current directory, or:

scons -c build export

to remove target files under build and export.

Additional files or directories to remove can be specified using the Clean function in the
SConscript files. Conversely, targets that would normally be removed by the -c invocation
can be retained by calling the NoClean function with those targets.

scons supports building multiple targets in parallel via a -j option that takes, as its
argument, the number of simultaneous tasks that may be spawned:

scons -j 4

builds four targets in parallel, for example.

scons can maintain a cache of target (derived) files that can be shared between multiple
builds. When caching is enabled in a SConscript file, any target files built by scons will
be copied to the cache. If an up-to-date target file is found in the cache, it will be
retrieved from the cache instead of being rebuilt locally. Caching behavior may be
disabled and controlled in other ways by the --cache-force, --cache-disable,
--cache-readonly, and --cache-show command-line options. The --random option is useful to
prevent multiple builds from trying to update the cache simultaneously.

By default, scons searches for known programming tools on various systems and initializes
itself based on what is found. On Windows systems which identify as win32, scons searches
in order for the Microsoft Visual C++ tools, the MinGW tool chain, the Intel compiler
tools, and the PharLap ETS compiler. On Windows system which identify as cygwin (that is,
if scons is invoked from a cygwin shell), the order changes to prefer the GCC toolchain
over the MSVC tools. On OS/2 systems, scons searches in order for the OS/2 compiler, the
GCC tool chain, and the Microsoft Visual C++ tools, On SGI IRIX, IBM AIX, Hewlett Packard
HP-UX, and Oracle Solaris systems, scons searches for the native compiler tools (MIPSpro,
Visual Age, aCC, and Forte tools respectively) and the GCC tool chain. On all other
platforms, including POSIX (Linux and UNIX) platforms, scons searches in order for the GCC
tool chain, and the Intel compiler tools. These default values may be overridden by
appropriate setting of construction variables.

scons requires Python 3.5 or higher. There should be no other dependencies or requirements
to run scons, although the pywin32 Python package is strongly recommended if running on
Windows systems.

OPTIONS

In general, scons supports the same command-line options as GNU Make and many of those
supported by cons.

-b
Ignored for compatibility with non-GNU versions of Make

-c, --clean, --remove
Clean up by removing all target files for which a construction command is specified.
Also remove any files or directories associated to the construction command using the
Clean function. Will not remove any targets specified by the NoClean function.

--cache-debug=file
Write debug information about derived-file caching to the specified file. If file is a
hyphen (-), the debug information is printed to the standard output. The printed
messages describe what signature-file names are being looked for in, retrieved from,
or written to the derived-file cache specified by CacheDir.

--cache-disable, --no-cache
Disable derived-file caching. scons will neither retrieve files from the cache nor
copy files to the cache. This option can be used to temporarily disable the cache
without modifying the build scripts.

--cache-force, --cache-populate
When using CacheDir, populate a derived-file cache by copying any already-existing,
up-to-date derived files to the cache, in addition to files built by this invocation.
This is useful to populate a new cache with all the current derived files, or to add
to the cache any derived files recently built with caching disabled via the
--cache-disable option.

--cache-readonly
Use the derived-file cache, if enabled, to retrieve files, but do not not update the
cache with any files actually built during this invocation.

--cache-show
When using a derived-file cache and retrieving a file from it, show the command that
would have been executed to build the file. Without this option, scons reports
"Retrieved `file' from cache.". This allows producing consistent output for build
logs, regardless of whether a target file was rebuilt or retrieved from the cache.

--config=mode
Control how the Configure call should use or generate the results of configuration
tests. modeshould be specified from among the following choices:

auto
scons will use its normal dependency mechanisms to decide if a test must be
rebuilt or not. This saves time by not running the same configuration tests every
time you invoke scons, but will overlook changes in system header files or
external commands (such as compilers) if you don't specify those dependecies
explicitly. This is the default behavior.

force
If this option is specified, all configuration tests will be re-run regardless of
whether the cached results are out of date. This can be used to explicitly force
the configuration tests to be updated in response to an otherwise unconfigured
change in a system header file or compiler.

cache
If this option is specified, no configuration tests will be rerun and all results
will be taken from cache. scons will report an error if --config=cache is
specified and a necessary test does not have any results in the cache.

-C directory, --directory=directory
Run as if scons was started in directory instead of the current working directory.
That is, change directory before searching for the SConstruct, Sconstruct, sconstruct,
SConstruct.py, Sconstruct.py or sconstruct.py file or doing anything else. When
multiple -C options are given, each subsequent non-absolute -C directory is
interpreted relative to the preceding one. This option is similar to using -f
directory/SConstruct, but -f does not search for any of the predefined SConstruct
names in the specified directory. See also options -u, -U and -D to change the
SConstruct search behavior when this option is used.

-D
Works exactly the same way as the -u option except for the way default targets are
handled. When this option is used and no targets are specified on the command line,
all default targets are built, whether or not they are below the current directory.

--debug=type[,type...]
Debug the build process. type specifies the kind of debugging info to emit. Multiple
types may be specified, separated by commas. The following entries show the recognized
types:

action-timestamps
Prints additional time profiling information. For each command, shows the absolute
start and end times. This may be useful in debugging parallel builds. Implies the
--debug=time option.

Available since scons 3.1.

count
Print how many objects are created of the various classes used internally by SCons
before and after reading the SConscript files and before and after building
targets. This is not supported when SCons is executed with the Python -O
(optimized) option or when the SCons modules have been compiled with optimization
(that is, when executing from *.pyo files).

duplicate
Print a line for each unlink/relink (or copy) of a variant file from its source
file. Includes debugging info for unlinking stale variant files, as well as
unlinking old targets before building them.

explain
Print an explanation of why scons is deciding to (re-)build the targets it selects
for building.

findlibs
Instruct the scanner that searches for libraries to print a message about each
potential library name it is searching for, and about the actual libraries it
finds.

includes
Print the include tree after each top-level target is built. This is generally
used to find out what files are included by the sources of a given derived file:

$ scons --debug=includes foo.o

memoizer
Prints a summary of hits and misses using the Memoizer, an internal subsystem that
counts how often SCons uses cached values in memory instead of recomputing them
each time they're needed.

memory
Prints how much memory SCons uses before and after reading the SConscript files
and before and after building targets.

objects
Prints a list of the various objects of the various classes used internally by
SCons.

pdb
Re-run scons under the control of the pdb Python debugger.

prepare
Print a line each time any target (internal or external) is prepared for building.
scons prints this for each target it considers, even if that target is up to date
(see also --debug=explain). This can help debug problems with targets that aren't
being built; it shows whether scons is at least considering them or not.

presub
Print the raw command line used to build each target before the construction
environment variables are substituted. Also shows which targets are being built by
this command. Output looks something like this:

$ scons --debug=presub
Building myprog.o with action(s):
$SHCC $SHCFLAGS $SHCCFLAGS $CPPFLAGS $_CPPINCFLAGS -c -o $TARGET $SOURCES
...

stacktrace
Prints an internal Python stack trace when encountering an otherwise unexplained
error.

time
Prints various time profiling information:

• The time spent executing each individual build command

• The total build time (time SCons ran from beginning to end)

• The total time spent reading and executing SConscript files

• The total time SCons itself spent running (that is, not counting reading and
executing SConscript files)

• The total time spent executing all build commands

• The elapsed wall-clock time spent executing those build commands

• The time spent processing each file passed to the SConscript function

(When scons is executed without the -j option, the elapsed wall-clock time will
typically be slightly longer than the total time spent executing all the build
commands, due to the SCons processing that takes place in between executing each
command. When scons is executed with the -j option, and your build configuration
allows good parallelization, the elapsed wall-clock time should be significantly
smaller than the total time spent executing all the build commands, since multiple
build commands and intervening SCons processing should take place in parallel.)

--diskcheck=type[,type...]
Enable specific checks for whether or not there is a file on disk where the SCons
configuration expects a directory (or vice versa), and whether or not RCS or SCCS
sources exist when searching for source and include files. The type argument can be
set to:

all
Enable all checks explicitly (the default behavior).

none
Disable all such checks.

match
to check that files and directories on disk match SCons' expected configuration.

rcs
Check for the existence of an RCS source for any missing source or include files.

sccs
Check for the existence of an SCCS source for any missing source or include files.

Multiple checks can be specified separated by commas. for example,
--diskcheck=sccs,rcs would still check for SCCS and RCS sources, but disable the check
for on-disk matches of files and directories. Disabling some or all of these checks
can provide a performance boost for large configurations, or when the configuration
will check for files and/or directories across networked or shared file systems, at
the slight increased risk of an incorrect build or of not handling errors gracefully
(if include files really should be found in SCCS or RCS, for example, or if a file
really does exist where the SCons configuration expects a directory).

--duplicate=ORDER
There are three ways to duplicate files in a build tree: hard links, soft (symbolic)
links and copies. The default behaviour of SCons is to prefer hard links to soft links
to copies. You can specify different behaviours with this option. ORDER must be one
of hard-soft-copy (the default), soft-hard-copy, hard-copy, soft-copy or copy. SCons
will attempt to duplicate files using the mechanisms in the specified order.

--enable-virtualenv
Import virtualenv-related variables to SCons.

-f file, --file=file, --makefile=file, --sconstruct=file
Use file as the initial SConscript file. Multiple -f options may be specified, in
which case scons will read all of the specified files.

-h, --help
Print a local help message for this project, if one is defined in the SConscript files
(see the Help function), plus a line that refers to the standard SCons help message.
If no local help message is defined, prints the standard SCons help message (as for
the -H option) plus help for any local options defined through AddOption. Exits after
displaying the appropriate message.

Note that use of this option requires SCons to process the SConscript files, so syntax
errors may cause the help message not to be displayed.

-H, --help-options
Print the standard help message about SCons command-line options and exit.

-i, --ignore-errors
Ignore all errors from commands executed to rebuild files.

-I directory, --include-dir=directory
Specifies a directory to search for imported Python modules. If several -I options are
used, the directories are searched in the order specified.

--ignore-virtualenv
Suppress importing virtualenv-related variables to SCons.

--implicit-cache
Cache implicit dependencies. This causes scons to use the implicit (scanned)
dependencies from the last time it was run instead of scanning the files for implicit
dependencies. This can significantly speed up SCons, but with the following
limitations:

scons will not detect changes to implicit dependency search paths (e.g. CPPPATH,
LIBPATH) that would ordinarily cause different versions of same-named files to be
used.

scons will miss changes in the implicit dependencies in cases where a new implicit
dependency is added earlier in the implicit dependency search path (e.g. CPPPATH,
LIBPATH) than a current implicit dependency with the same name.

--implicit-deps-changed
Forces SCons to ignore the cached implicit dependencies. This causes the implicit
dependencies to be rescanned and recached. This implies --implicit-cache.

--implicit-deps-unchanged
Force SCons to ignore changes in the implicit dependencies. This causes cached
implicit dependencies to always be used. This implies --implicit-cache.

--install-sandbox=path
When using the Install functions, prepend path to the installation paths such that all
installed files will be placed underneath path.

--interactive
Starts SCons in interactive mode. The SConscript files are read once and a scons>>>
prompt is printed. Targets may now be rebuilt by typing commands at interactive prompt
without having to re-read the SConscript files and re-initialize the dependency graph
from scratch.

SCons interactive mode supports the following commands:

build [OPTIONS] [TARGETS] ...
Builds the specified TARGETS (and their dependencies) with the specified SCons
command-line OPTIONS. b and scons are synonyms for build.

The following SCons command-line options affect the build command:

--cache-debug=FILE
--cache-disable, --no-cache
--cache-force, --cache-populate
--cache-readonly
--cache-show
--debug=TYPE
-i, --ignore-errors
-j N, --jobs=N
-k, --keep-going
-n, --no-exec, --just-print, --dry-run, --recon
-Q
-s, --silent, --quiet
--taskmastertrace=FILE
--tree=OPTIONS

Any other SCons command-line options that are specified do not cause errors but
have no effect on the build command (mainly because they affect how the SConscript
files are read, which only happens once at the beginning of interactive mode).

clean [OPTIONS] [TARGETS] ...
Cleans the specified TARGETS (and their dependencies) with the specified OPTIONS.
c is a synonym. This command is itself a synonym for build --clean

exit
Exits SCons interactive mode. You can also exit by terminating input (Ctrl+D UNIX
or Linux systems, (Ctrl+Z on Windows systems).

help [COMMAND]
Provides a help message about the commands available in SCons interactive mode. If
COMMAND is specified, h and ? are synonyms.

shell [COMMANDLINE]
Executes the specified COMMANDLINE in a subshell. If no COMMANDLINE is specified,
executes the interactive command interpreter specified in the SHELL environment
variable (on UNIX and Linux systems) or the COMSPEC environment variable (on
Windows systems). sh and ! are synonyms.

version
Prints SCons version information.

An empty line repeats the last typed command. Command-line editing can be used if the
readline module is available.

$ scons --interactive
scons: Reading SConscript files ...
scons: done reading SConscript files.
scons>>> build -n prog
scons>>> exit

-j N, --jobs=N
Specifies the maximum number of comcurrent jobs (commands) to run. If there is more
than one -j option, the last one is effective.

-k, --keep-going
Continue as much as possible after an error. The target that failed and those that
depend on it will not be remade, but other targets specified on the command line will
still be processed.

-m
Ignored for compatibility with non-GNU versions of Make.

--max-drift=SECONDS
Set the maximum expected drift in the modification time of files to SECONDS. This
value determines how long a file must be unmodified before its cached content
signature will be used instead of calculating a new content signature (MD5 checksum)
of the file's contents. The default value is 2 days, which means a file must have a
modification time of at least two days ago in order to have its cached content
signature used. A negative value means to never cache the content signature and to
ignore the cached value if there already is one. A value of 0 means to always use the
cached signature, no matter how old the file is.

--md5-chunksize=KILOBYTES
Set the block size used to compute MD5 signatures to KILOBYTES. This value determines
the size of the chunks which are read in at once when computing MD5 signatures. Files
below that size are fully stored in memory before performing the signature computation
while bigger files are read in block-by-block. A huge block-size leads to high memory
consumption while a very small block-size slows down the build considerably.

The default value is to use a chunk size of 64 kilobytes, which should be appropriate
for most uses.

-n, --just-print, --dry-run, --recon
No execute. Print the commands that would be executed to build any out-of-date target
files, but do not execute the commands.

--no-site-dir
Prevents the automatic addition of the standard site_scons dirs to sys.path. Also
prevents loading the site_scons/site_init.py modules if they exist, and prevents
adding their site_scons/site_tools dirs to the toolpath.

--profile=file
Run SCons under the Python profiler and save the results in the specified file. The
results may be analyzed using the Python pstats module.

-q, --question
Do not run any commands, or print anything. Just return an exit status that is zero if
the specified targets are already up to date, non-zero otherwise.

-Q
Quiets SCons status messages about reading SConscript files, building targets and
entering directories. Commands that are executed to rebuild target files are still
printed.

--random
Build dependencies in a random order. This is useful when building multiple trees
simultaneously with caching enabled, to prevent multiple builds from simultaneously
trying to build or retrieve the same target files.

-s, --silent, --quiet
Silent. Do not print commands that are executed to rebuild target files. Also
suppresses SCons status messages.

-S, --no-keep-going, --stop
Ignored for compatibility with GNU Make

--site-dir=dir
Uses the named dir as the site directory rather than the default site_scons
directories. This directory will be prepended to sys.path, the module dir/site_init.py
will be loaded if it exists, and dir/site_tools will be added to the default toolpath.

The default set of site_scons directories used when --site-dir is not specified
depends on the system platform, as follows. Directories are examined in the order
given, from most generic to most specific, so the last-executed site_init.py file is
the most specific one (which gives it the chance to override everything else), and the
directories are prepended to the paths, again so the last directory examined comes
first in the resulting path.

Windows:

%ALLUSERSPROFILE/Application Data/scons/site_scons
%USERPROFILE%/Local Settings/Application Data/scons/site_scons
%APPDATA%/scons/site_scons
%HOME%/.scons/site_scons
./site_scons

Mac OS X:

/Library/Application Support/SCons/site_scons
/opt/local/share/scons/site_scons (for MacPorts)
/sw/share/scons/site_scons (for Fink)
$HOME/Library/Application Support/SCons/site_scons
$HOME/.scons/site_scons
./site_scons

Solaris:

/opt/sfw/scons/site_scons
/usr/share/scons/site_scons
$HOME/.scons/site_scons
./site_scons

Linux, HPUX, and other Posix-like systems:

/usr/share/scons/site_scons
$HOME/.scons/site_scons
./site_scons

--stack-size=KILOBYTES
Set the size stack used to run threads to KILOBYTES. This value determines the stack
size of the threads used to run jobs. These threads execute the actions of the
builders for the nodes that are out-of-date. This option has no effect unless the
number of concurrent build jobs is larger than one (as set by -j N or --jobs=N on the
command line or SetOption in a script).

Using a stack size that is too small may cause stack overflow errors. This usually
shows up as segmentation faults that cause scons to abort before building anything.
Using a stack size that is too large will cause scons to use more memory than required
and may slow down the entire build process. The default value is to use a stack size
of 256 kilobytes, which should be appropriate for most uses. You should not need to
increase this value unless you encounter stack overflow errors.

-t, --touch
Ignored for compatibility with GNU Make. (Touching a file to make it appear up-to-date
is unnecessary when using scons.)

--taskmastertrace=file
Prints trace information to the specified file about how the internal Taskmaster
object evaluates and controls the order in which Nodes are built. A file name of - may
be used to specify the standard output.

--tree=type[,type...]
Prints a tree of the dependencies after each top-level target is built. This prints
out some or all of the tree, in various formats, depending on the type specified:

all
Print the entire dependency tree after each top-level target is built. This prints
out the complete dependency tree, including implicit dependencies and ignored
dependencies.

derived
Restricts the tree output to only derived (target) files, not source files.

linedraw
Draw the tree output using Unicode line-drawing characters instead of plain ASCII
text. This option acts as a modifier to the selected type(s). If specified alone,
without any type, it behaves as if all had been specified.

Available since scons 4.0.

status
Prints status information for each displayed node.

prune
Prunes the tree to avoid repeating dependency information for nodes that have
already been displayed. Any node that has already been displayed will have its
name printed in [square brackets], as an indication that the dependencies for that
node can be found by searching for the relevant output higher up in the tree.

Multiple type choices may be specified, separated by commas:

# Prints only derived files, with status information:
scons --tree=derived,status

# Prints all dependencies of target, with status information
# and pruning dependencies of already-visited Nodes:
scons --tree=all,prune,status target

-u, --up, --search-up
Walks up the directory structure until an SConstruct, Sconstruct, sconstruct,
SConstruct.py, Sconstruct.py or sconstruct.py file is found, and uses that as the top
of the directory tree. If no targets are specified on the command line, only targets
at or below the current directory will be built.

-U
Works exactly the same way as the -u option except for the way default targets are
handled. When this option is used and no targets are specified on the command line,
all default targets that are defined in the SConscript(s) in the current directory are
built, regardless of what directory the resultant targets end up in.

-v, --version
Print the scons version, copyright information, list of authors, and any other
relevant information. Then exit.

-w, --print-directory
Print a message containing the working directory before and after other processing.

--no-print-directory
Turn off -w, even if it was turned on implicitly.

--warn=type, --warn=no-type
Enable or disable (with the no- prefix) warnings. type specifies the type of warnings
to be enabled or disabled:

all
All warnings.

cache-version
Warnings about the derived-file cache directory specified by CacheDir not using
the latest configuration information. These warnings are enabled by default.

cache-write-error
Warnings about errors trying to write a copy of a built file to a specified
derived-file cache specified by CacheDir. These warnings are disabled by default.

corrupt-sconsign
Warnings about unfamiliar signature data in .sconsign files. These warnings are
enabled by default.

dependency
Warnings about dependencies. These warnings are disabled by default.

deprecated
Warnings about use of currently deprecated features. These warnings are enabled by
default. Not all deprecation warnings can be disabled with the
--warn=no-deprecated option as some deprecated features which are late in the
deprecation cycle may have been designated as mandatory warnings, and these will
still display. Warnings for certain deprecated features may also be enabled or
disabled individually; see below.

duplicate-environment
Warnings about attempts to specify a build of a target with two different
construction environments that use the same action. These warnings are enabled by
default.

fortran-cxx-mix
Warnings about linking Fortran and C++ object files in a single executable, which
can yield unpredictable behavior with some compilers.

future-deprecated
Warnings about features that will be deprecated in the future. Such warnings are
disabled by default. Enabling future deprecation warnings is recommended for
projects that redistribute SCons configurations for other users to build, so that
the project can be warned as soon as possible about to-be-deprecated features that
may require changes to the configuration.

link
Warnings about link steps.

misleading-keywords
Warnings about the use of two commonly misspelled keywords targets and sources to
Builder calls. The correct spelling is the singular form, even though target and
source can themselves refer to lists of names or nodes.

missing-sconscript
Warnings about missing SConscript files. These warnings are enabled by default.

no-object-count
Warnings about the --debug=object feature not working when scons is run with the
Python -O option or from optimized Python (.pyo) modules.

no-parallel-support
Warnings about the version of Python not being able to support parallel builds
when the -j option is used. These warnings are enabled by default.

python-version
Warnings about running SCons with a deprecated version of Python. These warnings
are enabled by default.

reserved-variable
Warnings about attempts to set the reserved construction variable names
$CHANGED_SOURCES, $CHANGED_TARGETS, $TARGET, $TARGETS, $SOURCE, $SOURCES,
$UNCHANGED_SOURCES or $UNCHANGED_TARGETS. These warnings are disabled by default.

stack-size
Warnings about requests to set the stack size that could not be honored. These
warnings are enabled by default.

target_not_build
Warnings about a build rule not building the expected targets. These warnings are
disabled by default.

-Y repository, --repository=repository, --srcdir=repository
Search the specified repository for any input and target files not found in the local
directory hierarchy. Multiple -Y options may be specified, in which case the
repositories are searched in the order specified.

CONFIGURATION FILE REFERENCE

Construction Environments
A Construction Environment is the basic means by which SConscript files communicate build
information to scons. A new construction environment is created using the Environment
function:

env = Environment()

Construction environment attributes called Construction Variables may be set either by
specifying them as keyword arguments when the object is created or by assigning them a
value after the object is created:

env = Environment(FOO='foo')
env['BAR'] = 'bar'

An existing construction environment can be duplicated by calling the env.Clone method.
Without arguments, it will be a copy with the same settings. Otherwise, env.Clone takes
the same arguments as Environment, and uses the arguments to create a modified copy.

SCons also provides a special construction environment called the Default Environment. The
default environment is used only for global functions, that is, construction activities
called without the context of a regular construction environment. See DefaultEnvironment
for more information.

As a convenience, construction variables may also be set or modified by the parse_flags
keyword argument, which applies the env.MergeFlags method (described below) to the
argument value after all other processing is completed. This is useful either if the exact
content of the flags is unknown (for example, read from a control file) or if the flags
need to be distributed to a number of construction variables.

env = Environment(parse_flags='-Iinclude -DEBUG -lm')

This example adds 'include' to the CPPPATH construction variable 'EBUG' to CPPDEFINES, and
'm' to LIBS. env.ParseFlags describes how these arguments are distributed to construction
variables.

By default, a new construction environment is initialized with a set of builder methods
and construction variables that are appropriate for the current platform. An optional
platform keyword argument may be used to specify that the construction environment should
be initialized for a different platform:

env = Environment(platform='cygwin')
env = Environment(platform='os2')
env = Environment(platform='posix')
env = Environment(platform='win32')

Specifying a platform initializes the appropriate construction variables in the
environment to use and generate file names with prefixes and suffixes appropriate for that
platform.

Note that the win32 platform adds the SystemDrive and SystemRoot variables from the user's
external environment to the construction environment's ENV dictionary. This is so that any
executed commands that use sockets to connect with other systems (such as fetching source
files from external CVS repository specifications like
:pserver:anonymous@cvs.sourceforge.net:/cvsroot/scons) will work on Windows systems.

The platform argument may be a function or callable object, in which case the Environment
method will call it to update the new construction environment:

def my_platform(env):
env['VAR'] = 'xyzzy'

env = Environment(platform=my_platform)

Tools
SCons has a large number of predefined tools which are used to help initialize the
construction environment, and additional tools can be added. An scons tool specification
is only responsible for setup. For example, if the SConscript file declares the need to
construct an object file from a C-language source file by calling the Object builder, then
a tool representing an available C compiler needs to have run first, to set up the builder
and all the construction variables it needs, in that construction environment. Normally
this happens invisibly: scons has per-platform lists of default tools, and it runs through
those tools, calling the ones which are actually applicable (skipping those where
necessary programs are not installed on the build system, etc.).

A specific set of tools with which to initialize the environment when creating it may be
specified using the optional keyword argument tools. This is useful to override the
defaults, to specify non-default built-in tools, and to supply added tools:

env = Environment(tools=['msvc', 'lex'])

Tools can also be called by using the Tool method (see below).

The tools argument overrides the default tool list, it does not add to it, so be sure to
include all the tools you need. For example if you are building a c/c++ program you must
specify a tool for at least a compiler and a linker, as in tools=['clang', 'link']. The
tool name 'default' can be used to retain the default list.

If no tools list is specified, or the list includes 'default', then scons will detect
usable tools, using the value of PATH in the ENV construction variable (not the external
PATH from os.environ) for looking up any backing programs, and the platform name in effect
to determine the default tools for that platform. Changing the PATH variable after the
construction environment is constructed will not cause the tools to be redetected.

To help locate added tools, specify the toolpath keyword argument:

env = Environment(tools=['default', 'foo'], toolpath=['tools'])

This looks for a tool specification in tools/foo.py as well as using the ordinary default
tools for the platform.

Tools in the toolpath are used in preference to any of the built-in ones. For example,
adding a tool gcc.py to the toolpath directory would override the built-in gcc tool. The
toolpath is stored in the environment and will be picked up by subsequent calls to the
Clone and Tool methods:

base = Environment(toolpath=['custom_path'])
derived = base.Clone(tools=['custom_tool'])
derived.CustomBuilder()

A tool specification must include two functions:

generate(env, **kwargs)
Modifies the environment referenced by env to set up variables so that the facilities
represented by the tool can be executed. It may use any keyword arguments that the
user supplies in kwargs to vary its initialization.

exists(env)
Return True if the tool can be called. Usually this means looking up one or more known
programs using the PATH from the supplied env, but the tool can make the "exists"
decision in any way it chooses.

The elements of the tools list may also be functions or callable objects, in which case
the Environment method will call those objects to update the new construction environment
(see Tool for more details):

def my_tool(env):
env['XYZZY'] = 'xyzzy'

env = Environment(tools=[my_tool])

The individual elements of the tools list may also themselves be lists or tuples of the
form (toolname, kw_dict). SCons searches for the toolname specification file as described
above, and passes kw_dict, which must be a dictionary, as keyword arguments to the tool's
generate function. The generate function can use the arguments to modify the tool's
behavior by setting up the environment in different ways or otherwise changing its
initialization.

# in tools/my_tool.py:
def generate(env, **kwargs):
# Sets MY_TOOL to the value of keyword 'arg1' '1' if not supplied
env['MY_TOOL'] = kwargs.get('arg1', '1')

def exists(env):
return True

# in SConstruct:
env = Environment(tools=['default', ('my_tool', {'arg1': 'abc'})],
toolpath=['tools'])

The tool definition (my_tool in the example) can use the PLATFORM variable from the
construction environment it is passed to customize the tool for different platforms.

Tools can be "nested" - that is, they can be located within a subdirectory in the
toolpath. A nested tool name uses a dot to represent a directory separator

# namespaced builder
env = Environment(ENV=os.environ, tools=['SubDir1.SubDir2.SomeTool'])
env.SomeTool(targets, sources)

# Search Paths
# SCons\Tool\SubDir1\SubDir2\SomeTool.py
# SCons\Tool\SubDir1\SubDir2\SomeTool\__init__.py
# .\site_scons\site_tools\SubDir1\SubDir2\SomeTool.py
# .\site_scons\site_tools\SubDir1\SubDir2\SomeTool\__init__.py

SCons supports the following tool specifications out of the box:

386asm
Sets construction variables for the 386ASM assembler for the Phar Lap ETS embedded
operating system.

Sets: $AS, $ASCOM, $ASFLAGS, $ASPPCOM, $ASPPFLAGS.

Uses: $CC, $CPPFLAGS, $_CPPDEFFLAGS, $_CPPINCFLAGS.

aixc++
Sets construction variables for the IMB xlc / Visual Age C++ compiler.

Sets: $CXX, $CXXVERSION, $SHCXX, $SHOBJSUFFIX.

aixcc
Sets construction variables for the IBM xlc / Visual Age C compiler.

Sets: $CC, $CCVERSION, $SHCC.

aixf77
Sets construction variables for the IBM Visual Age f77 Fortran compiler.

Sets: $F77, $SHF77.

aixlink
Sets construction variables for the IBM Visual Age linker.

Sets: $LINKFLAGS, $SHLIBSUFFIX, $SHLINKFLAGS.

applelink
Sets construction variables for the Apple linker (similar to the GNU linker).

Sets: $APPLELINK_COMPATIBILITY_VERSION, $APPLELINK_CURRENT_VERSION,
$APPLELINK_NO_COMPATIBILITY_VERSION, $APPLELINK_NO_CURRENT_VERSION,
$FRAMEWORKPATHPREFIX, $LDMODULECOM, $LDMODULEFLAGS, $LDMODULEPREFIX, $LDMODULESUFFIX,
$LINKCOM, $SHLINKCOM, $SHLINKFLAGS, $_APPLELINK_COMPATIBILITY_VERSION,
$_APPLELINK_CURRENT_VERSION, $_FRAMEWORKPATH, $_FRAMEWORKS.

Uses: $FRAMEWORKSFLAGS.

ar
Sets construction variables for the ar library archiver.

Sets: $AR, $ARCOM, $ARFLAGS, $LIBPREFIX, $LIBSUFFIX, $RANLIB, $RANLIBCOM,
$RANLIBFLAGS.

as
Sets construction variables for the as assembler.

Sets: $AS, $ASCOM, $ASFLAGS, $ASPPCOM, $ASPPFLAGS.

Uses: $CC, $CPPFLAGS, $_CPPDEFFLAGS, $_CPPINCFLAGS.

bcc32
Sets construction variables for the bcc32 compiler.

Sets: $CC, $CCCOM, $CCFLAGS, $CFILESUFFIX, $CFLAGS, $CPPDEFPREFIX, $CPPDEFSUFFIX,
$INCPREFIX, $INCSUFFIX, $SHCC, $SHCCCOM, $SHCCFLAGS, $SHCFLAGS, $SHOBJSUFFIX.

Uses: $_CPPDEFFLAGS, $_CPPINCFLAGS.

cc
Sets construction variables for generic POSIX C compilers.

Sets: $CC, $CCCOM, $CCFLAGS, $CFILESUFFIX, $CFLAGS, $CPPDEFPREFIX, $CPPDEFSUFFIX,
$FRAMEWORKPATH, $FRAMEWORKS, $INCPREFIX, $INCSUFFIX, $SHCC, $SHCCCOM, $SHCCFLAGS,
$SHCFLAGS, $SHOBJSUFFIX.

Uses: $CCCOMSTR, $PLATFORM, $SHCCCOMSTR.

clang
Set construction variables for the Clang C compiler.

Sets: $CC, $CCVERSION, $SHCCFLAGS.

clangxx
Set construction variables for the Clang C++ compiler.

Sets: $CXX, $CXXVERSION, $SHCXXFLAGS, $SHOBJSUFFIX,
$STATIC_AND_SHARED_OBJECTS_ARE_THE_SAME.

compilation_db
Sets up CompilationDatabase builder which generates a clang tooling compatible
compilation database.

Sets: $COMPILATIONDB_COMSTR, $COMPILATIONDB_USE_ABSPATH.

cvf
Sets construction variables for the Compaq Visual Fortran compiler.

Sets: $FORTRAN, $FORTRANCOM, $FORTRANMODDIR, $FORTRANMODDIRPREFIX,
$FORTRANMODDIRSUFFIX, $FORTRANPPCOM, $OBJSUFFIX, $SHFORTRANCOM, $SHFORTRANPPCOM.

Uses: $CPPFLAGS, $FORTRANFLAGS, $SHFORTRANFLAGS, $_CPPDEFFLAGS, $_FORTRANINCFLAGS,
$_FORTRANMODFLAG.

cXX
Sets construction variables for generic POSIX C++ compilers.

Sets: $CPPDEFPREFIX, $CPPDEFSUFFIX, $CXX, $CXXCOM, $CXXFILESUFFIX, $CXXFLAGS,
$INCPREFIX, $INCSUFFIX, $OBJSUFFIX, $SHCXX, $SHCXXCOM, $SHCXXFLAGS, $SHOBJSUFFIX.

Uses: $CXXCOMSTR, $SHCXXCOMSTR.

cyglink
Set construction variables for cygwin linker/loader.

Sets: $IMPLIBPREFIX, $IMPLIBSUFFIX, $LDMODULEVERSIONFLAGS, $LINKFLAGS, $RPATHPREFIX,
$RPATHSUFFIX, $SHLIBPREFIX, $SHLIBSUFFIX, $SHLIBVERSIONFLAGS, $SHLINKCOM,
$SHLINKFLAGS, $_LDMODULEVERSIONFLAGS, $_SHLIBVERSIONFLAGS.

default
Sets construction variables for a default list of Tool modules. Use default in the
tools list to retain the original defaults, since the tools parameter is treated as a
literal statement of the tools to be made available in that construction environment,
not an addition.

The list of tools selected by default is not static, but is dependent both on the
platform and on the software installed on the platform. Some tools will not initialize
if an underlying command is not found, and some tools are selected from a list of
choices on a first-found basis. The finished tool list can be examined by inspecting
the TOOLS construction variable in the construction environment.

On all platforms, all tools from the following list are selected whose respective
conditions are met: filesystem, wix, lex, yacc, rpcgen, swig, jar, javac, javah, rmic,
dvipdf, dvips, gs, tex, latex, pdflatex, pdftex, tar, zip, textfile.

On Linux systems, the default tools list selects (first-found): a C compiler from gcc,
intelc, icc, cc; a C++ compiler from g++, intelc, icc, cxx; an assembler from gas,
nasm, masm; a linker from gnulink, ilink; a Fortran compiler from gfortran, g77,
ifort, ifl, f95, f90, f77; and a static archiver 'ar'. It also selects all found from
the list m4, rpm.

On Windows systems, the default tools list selects (first-found): a C compiler from
msvc, mingw, gcc, intelc, icl, icc, cc, bcc32; a C++ compiler from msvc, intelc, icc,
g++, cxx, bcc32; an assembler from masm, nasm, gas, 386asm; a linker from mslink,
gnulink, ilink, linkloc, ilink32; a Fortran compiler from gfortran, g77, ifl, cvf,
f95, f90, fortran; and a static archiver from mslib, ar, tlib; It also selects all
found from the list msvs, midl.

On MacOS systems, the default tools list selects (first-found): a C compiler from gcc,
cc; a C++ compiler from g++, cxx; an assembler 'as'; a linker from applelink, gnulink;
a Fortran compiler from gfortran, f95, f90, g77; and a static archiver ar. It also
selects all found from the list m4, rpm.

Default lists for other platforms can be found by examining the scons source code (see
SCons/Tool/__init__.py).

dmd
Sets construction variables for D language compiler DMD.

Sets: $DC, $DCOM, $DDEBUG, $DDEBUGPREFIX, $DDEBUGSUFFIX, $DFILESUFFIX, $DFLAGPREFIX,
$DFLAGS, $DFLAGSUFFIX, $DINCPREFIX, $DINCSUFFIX, $DLIB, $DLIBCOM, $DLIBDIRPREFIX,
$DLIBDIRSUFFIX, $DLIBFLAGPREFIX, $DLIBFLAGSUFFIX, $DLIBLINKPREFIX, $DLIBLINKSUFFIX,
$DLINK, $DLINKCOM, $DLINKFLAGPREFIX, $DLINKFLAGS, $DLINKFLAGSUFFIX, $DPATH,
$DRPATHPREFIX, $DRPATHSUFFIX, $DShLibSonameGenerator, $DVERPREFIX, $DVERSIONS,
$DVERSUFFIX, $SHDC, $SHDCOM, $SHDLIBVERSION, $SHDLIBVERSIONFLAGS, $SHDLINK,
$SHDLINKCOM, $SHDLINKFLAGS.

docbook
This tool tries to make working with Docbook in SCons a little easier. It provides
several toolchains for creating different output formats, like HTML or PDF. Contained
in the package is a distribution of the Docbook XSL stylesheets as of version 1.76.1.
As long as you don't specify your own stylesheets for customization, these official
versions are picked as default...which should reduce the inevitable setup hassles for
you.

Implicit dependencies to images and XIncludes are detected automatically if you meet
the HTML requirements. The additional stylesheet utils/xmldepend.xsl by Paul DuBois is
used for this purpose.

Note, that there is no support for XML catalog resolving offered! This tool calls the
XSLT processors and PDF renderers with the stylesheets you specified, that's it. The
rest lies in your hands and you still have to know what you're doing when resolving
names via a catalog.

For activating the tool "docbook", you have to add its name to the Environment
constructor, like this

env = Environment(tools=['docbook'])

On its startup, the Docbook tool tries to find a required xsltproc processor, and a
PDF renderer, e.g. fop. So make sure that these are added to your system's
environment PATH and can be called directly, without specifying their full path.

For the most basic processing of Docbook to HTML, you need to have installed

• the Python lxml binding to libxml2, or

• a standalone XSLT processor, currently detected are xsltproc, saxon, saxon-xslt
and xalan.

Rendering to PDF requires you to have one of the applications fop or xep installed.

Creating a HTML or PDF document is very simple and straightforward. Say

env = Environment(tools=['docbook'])
env.DocbookHtml('manual.html', 'manual.xml')
env.DocbookPdf('manual.pdf', 'manual.xml')

to get both outputs from your XML source manual.xml. As a shortcut, you can give the
stem of the filenames alone, like this:

env = Environment(tools=['docbook'])
env.DocbookHtml('manual')
env.DocbookPdf('manual')

and get the same result. Target and source lists are also supported:

env = Environment(tools=['docbook'])
env.DocbookHtml(['manual.html','reference.html'], ['manual.xml','reference.xml'])

or even

env = Environment(tools=['docbook'])
env.DocbookHtml(['manual','reference'])

Important
Whenever you leave out the list of sources, you may not specify a file extension!
The Tool uses the given names as file stems, and adds the suffixes for target and
source files accordingly.
The rules given above are valid for the Builders DocbookHtml, DocbookPdf, DocbookEpub,
DocbookSlidesPdf and DocbookXInclude. For the DocbookMan transformation you can
specify a target name, but the actual output names are automatically set from the
refname entries in your XML source.

The Builders DocbookHtmlChunked, DocbookHtmlhelp and DocbookSlidesHtml are special, in
that:

1. they create a large set of files, where the exact names and their number depend on
the content of the source file, and

2. the main target is always named index.html, i.e. the output name for the XSL
transformation is not picked up by the stylesheets.

As a result, there is simply no use in specifying a target HTML name. So the basic
syntax for these builders is always:

env = Environment(tools=['docbook'])
env.DocbookHtmlhelp('manual')

If you want to use a specific XSL file, you can set the additional xsl parameter to
your Builder call as follows:

env.DocbookHtml('other.html', 'manual.xml', xsl='html.xsl')

Since this may get tedious if you always use the same local naming for your customized
XSL files, e.g. html.xsl for HTML and pdf.xsl for PDF output, a set of variables for
setting the default XSL name is provided. These are:

DOCBOOK_DEFAULT_XSL_HTML
DOCBOOK_DEFAULT_XSL_HTMLCHUNKED
DOCBOOK_DEFAULT_XSL_HTMLHELP
DOCBOOK_DEFAULT_XSL_PDF
DOCBOOK_DEFAULT_XSL_EPUB
DOCBOOK_DEFAULT_XSL_MAN
DOCBOOK_DEFAULT_XSL_SLIDESPDF
DOCBOOK_DEFAULT_XSL_SLIDESHTML

and you can set them when constructing your environment:

env = Environment(tools=['docbook'],
DOCBOOK_DEFAULT_XSL_HTML='html.xsl',
DOCBOOK_DEFAULT_XSL_PDF='pdf.xsl')
env.DocbookHtml('manual') # now uses html.xsl

Sets: $DOCBOOK_DEFAULT_XSL_EPUB, $DOCBOOK_DEFAULT_XSL_HTML,
$DOCBOOK_DEFAULT_XSL_HTMLCHUNKED, $DOCBOOK_DEFAULT_XSL_HTMLHELP,
$DOCBOOK_DEFAULT_XSL_MAN, $DOCBOOK_DEFAULT_XSL_PDF, $DOCBOOK_DEFAULT_XSL_SLIDESHTML,
$DOCBOOK_DEFAULT_XSL_SLIDESPDF, $DOCBOOK_FOP, $DOCBOOK_FOPCOM, $DOCBOOK_FOPFLAGS,
$DOCBOOK_XMLLINT, $DOCBOOK_XMLLINTCOM, $DOCBOOK_XMLLINTFLAGS, $DOCBOOK_XSLTPROC,
$DOCBOOK_XSLTPROCCOM, $DOCBOOK_XSLTPROCFLAGS, $DOCBOOK_XSLTPROCPARAMS.

Uses: $DOCBOOK_FOPCOMSTR, $DOCBOOK_XMLLINTCOMSTR, $DOCBOOK_XSLTPROCCOMSTR.

dvi
Attaches the DVI builder to the construction environment.

dvipdf
Sets construction variables for the dvipdf utility.

Sets: $DVIPDF, $DVIPDFCOM, $DVIPDFFLAGS.

Uses: $DVIPDFCOMSTR.

dvips
Sets construction variables for the dvips utility.

Sets: $DVIPS, $DVIPSFLAGS, $PSCOM, $PSPREFIX, $PSSUFFIX.

Uses: $PSCOMSTR.

f03
Set construction variables for generic POSIX Fortran 03 compilers.

Sets: $F03, $F03COM, $F03FLAGS, $F03PPCOM, $SHF03, $SHF03COM, $SHF03FLAGS,
$SHF03PPCOM, $_F03INCFLAGS.

Uses: $F03COMSTR, $F03PPCOMSTR, $SHF03COMSTR, $SHF03PPCOMSTR.

f08
Set construction variables for generic POSIX Fortran 08 compilers.

Sets: $F08, $F08COM, $F08FLAGS, $F08PPCOM, $SHF08, $SHF08COM, $SHF08FLAGS,
$SHF08PPCOM, $_F08INCFLAGS.

Uses: $F08COMSTR, $F08PPCOMSTR, $SHF08COMSTR, $SHF08PPCOMSTR.

f77
Set construction variables for generic POSIX Fortran 77 compilers.

Sets: $F77, $F77COM, $F77FILESUFFIXES, $F77FLAGS, $F77PPCOM, $F77PPFILESUFFIXES,
$FORTRAN, $FORTRANCOM, $FORTRANFLAGS, $SHF77, $SHF77COM, $SHF77FLAGS, $SHF77PPCOM,
$SHFORTRAN, $SHFORTRANCOM, $SHFORTRANFLAGS, $SHFORTRANPPCOM, $_F77INCFLAGS.

Uses: $F77COMSTR, $F77PPCOMSTR, $FORTRANCOMSTR, $FORTRANPPCOMSTR, $SHF77COMSTR,
$SHF77PPCOMSTR, $SHFORTRANCOMSTR, $SHFORTRANPPCOMSTR.

f90
Set construction variables for generic POSIX Fortran 90 compilers.

Sets: $F90, $F90COM, $F90FLAGS, $F90PPCOM, $SHF90, $SHF90COM, $SHF90FLAGS,
$SHF90PPCOM, $_F90INCFLAGS.

Uses: $F90COMSTR, $F90PPCOMSTR, $SHF90COMSTR, $SHF90PPCOMSTR.

f95
Set construction variables for generic POSIX Fortran 95 compilers.

Sets: $F95, $F95COM, $F95FLAGS, $F95PPCOM, $SHF95, $SHF95COM, $SHF95FLAGS,
$SHF95PPCOM, $_F95INCFLAGS.

Uses: $F95COMSTR, $F95PPCOMSTR, $SHF95COMSTR, $SHF95PPCOMSTR.

fortran
Set construction variables for generic POSIX Fortran compilers.

Sets: $FORTRAN, $FORTRANCOM, $FORTRANFLAGS, $SHFORTRAN, $SHFORTRANCOM,
$SHFORTRANFLAGS, $SHFORTRANPPCOM.

Uses: $FORTRANCOMSTR, $FORTRANPPCOMSTR, $SHFORTRANCOMSTR, $SHFORTRANPPCOMSTR.

g++
Set construction variables for the gXX C++ compiler.

Sets: $CXX, $CXXVERSION, $SHCXXFLAGS, $SHOBJSUFFIX.

g77
Set construction variables for the g77 Fortran compiler. Calls the f77 Tool module to
set variables.

gas
Sets construction variables for the gas assembler. Calls the as module.

Sets: $AS.

gcc
Set construction variables for the gcc C compiler.

Sets: $CC, $CCVERSION, $SHCCFLAGS.

gdc
Sets construction variables for the D language compiler GDC.

gettext
This is actually a toolset, which supports internationalization and localization of
software being constructed with SCons. The toolset loads following tools:

• xgettext - to extract internationalized messages from source code to POT file(s),

• msginit - may be optionally used to initialize PO files,

• msgmerge - to update PO files, that already contain translated messages,

• msgfmt - to compile textual PO file to binary installable MO file.

When you enable gettext, it internally loads all abovementioned tools, so you're
encouraged to see their individual documentation.

Each of the above tools provides its own builder(s) which may be used to perform
particular activities related to software internationalization. You may be however
interested in top-level builder Translate described few paragraphs later.

To use gettext tools add 'gettext' tool to your environment:

env = Environment( tools = ['default', 'gettext'] )

gfortran
Sets construction variables for the GNU F95/F2003 GNU compiler.

Sets: $F77, $F90, $F95, $FORTRAN, $SHF77, $SHF77FLAGS, $SHF90, $SHF90FLAGS, $SHF95,
$SHF95FLAGS, $SHFORTRAN, $SHFORTRANFLAGS.

gnulink
Set construction variables for GNU linker/loader.

Sets: $LDMODULEVERSIONFLAGS, $RPATHPREFIX, $RPATHSUFFIX, $SHLIBVERSIONFLAGS,
$SHLINKFLAGS, $_LDMODULESONAME, $_SHLIBSONAME.

gs
This Tool sets the required construction variables for working with the Ghostscript
command. It also registers an appropriate Action with the PDF Builder (PDF), such that
the conversion from PS/EPS to PDF happens automatically for the TeX/LaTeX toolchain.
Finally, it adds an explicit Ghostscript Builder (Gs) to the environment.

Sets: $GS, $GSCOM, $GSFLAGS.

Uses: $GSCOMSTR.

hpc++
Set construction variables for the compilers aCC on HP/UX systems.

hpcc
Set construction variables for the aCC on HP/UX systems. Calls the cXX tool for
additional variables.

Sets: $CXX, $CXXVERSION, $SHCXXFLAGS.

hplink
Sets construction variables for the linker on HP/UX systems.

Sets: $LINKFLAGS, $SHLIBSUFFIX, $SHLINKFLAGS.

icc
Sets construction variables for the icc compiler on OS/2 systems.

Sets: $CC, $CCCOM, $CFILESUFFIX, $CPPDEFPREFIX, $CPPDEFSUFFIX, $CXXCOM,
$CXXFILESUFFIX, $INCPREFIX, $INCSUFFIX.

Uses: $CCFLAGS, $CFLAGS, $CPPFLAGS, $_CPPDEFFLAGS, $_CPPINCFLAGS.

icl
Sets construction variables for the Intel C/C++ compiler. Calls the intelc Tool module
to set its variables.

ifl
Sets construction variables for the Intel Fortran compiler.

Sets: $FORTRAN, $FORTRANCOM, $FORTRANPPCOM, $SHFORTRANCOM, $SHFORTRANPPCOM.

Uses: $CPPFLAGS, $FORTRANFLAGS, $_CPPDEFFLAGS, $_FORTRANINCFLAGS.

ifort
Sets construction variables for newer versions of the Intel Fortran compiler for
Linux.

Sets: $F77, $F90, $F95, $FORTRAN, $SHF77, $SHF77FLAGS, $SHF90, $SHF90FLAGS, $SHF95,
$SHF95FLAGS, $SHFORTRAN, $SHFORTRANFLAGS.

ilink
Sets construction variables for the ilink linker on OS/2 systems.

Sets: $LIBDIRPREFIX, $LIBDIRSUFFIX, $LIBLINKPREFIX, $LIBLINKSUFFIX, $LINK, $LINKCOM,
$LINKFLAGS.

ilink32
Sets construction variables for the Borland ilink32 linker.

Sets: $LIBDIRPREFIX, $LIBDIRSUFFIX, $LIBLINKPREFIX, $LIBLINKSUFFIX, $LINK, $LINKCOM,
$LINKFLAGS.

install
Sets construction variables for file and directory installation.

Sets: $INSTALL, $INSTALLSTR.

intelc
Sets construction variables for the Intel C/C++ compiler (Linux and Windows, version 7
and later). Calls the gcc or msvc (on Linux and Windows, respectively) to set
underlying variables.

Sets: $AR, $CC, $CXX, $INTEL_C_COMPILER_VERSION, $LINK.

jar
Sets construction variables for the jar utility.

Sets: $JAR, $JARCOM, $JARFLAGS, $JARSUFFIX.

Uses: $JARCOMSTR.

javac
Sets construction variables for the javac compiler.

Sets: $JAVABOOTCLASSPATH, $JAVAC, $JAVACCOM, $JAVACFLAGS, $JAVACLASSPATH,
$JAVACLASSSUFFIX, $JAVAINCLUDES, $JAVASOURCEPATH, $JAVASUFFIX.

Uses: $JAVACCOMSTR.

javah
Sets construction variables for the javah tool.

Sets: $JAVACLASSSUFFIX, $JAVAH, $JAVAHCOM, $JAVAHFLAGS.

Uses: $JAVACLASSPATH, $JAVAHCOMSTR.

latex
Sets construction variables for the latex utility.

Sets: $LATEX, $LATEXCOM, $LATEXFLAGS.

Uses: $LATEXCOMSTR.

ldc
Sets construction variables for the D language compiler LDC2.

lex
Sets construction variables for the lex lexical analyser.

Sets: $LEX, $LEXCOM, $LEXFLAGS, $LEXUNISTD.

Uses: $LEXCOMSTR.

link
Sets construction variables for generic POSIX linkers. This is a "smart" linker tool
which selects a compiler to complete the linking based on the types of source files.

Sets: $LDMODULE, $LDMODULECOM, $LDMODULEFLAGS, $LDMODULENOVERSIONSYMLINKS,
$LDMODULEPREFIX, $LDMODULESUFFIX, $LDMODULEVERSION, $LDMODULEVERSIONFLAGS,
$LIBDIRPREFIX, $LIBDIRSUFFIX, $LIBLINKPREFIX, $LIBLINKSUFFIX, $LINK, $LINKCOM,
$LINKFLAGS, $SHLIBSUFFIX, $SHLINK, $SHLINKCOM, $SHLINKFLAGS, $__LDMODULEVERSIONFLAGS,
$__SHLIBVERSIONFLAGS.

Uses: $LDMODULECOMSTR, $LINKCOMSTR, $SHLINKCOMSTR.

linkloc
Sets construction variables for the LinkLoc linker for the Phar Lap ETS embedded
operating system.

Sets: $LIBDIRPREFIX, $LIBDIRSUFFIX, $LIBLINKPREFIX, $LIBLINKSUFFIX, $LINK, $LINKCOM,
$LINKFLAGS, $SHLINK, $SHLINKCOM, $SHLINKFLAGS.

Uses: $LINKCOMSTR, $SHLINKCOMSTR.

m4
Sets construction variables for the m4 macro processor.

Sets: $M4, $M4COM, $M4FLAGS.

Uses: $M4COMSTR.

masm
Sets construction variables for the Microsoft assembler.

Sets: $AS, $ASCOM, $ASFLAGS, $ASPPCOM, $ASPPFLAGS.

Uses: $ASCOMSTR, $ASPPCOMSTR, $CPPFLAGS, $_CPPDEFFLAGS, $_CPPINCFLAGS.

midl
Sets construction variables for the Microsoft IDL compiler.

Sets: $MIDL, $MIDLCOM, $MIDLFLAGS.

Uses: $MIDLCOMSTR.

mingw
Sets construction variables for MinGW (Minimal Gnu on Windows).

Sets: $AS, $CC, $CXX, $LDMODULECOM, $LIBPREFIX, $LIBSUFFIX, $OBJSUFFIX, $RC, $RCCOM,
$RCFLAGS, $RCINCFLAGS, $RCINCPREFIX, $RCINCSUFFIX, $SHCCFLAGS, $SHCXXFLAGS,
$SHLINKCOM, $SHLINKFLAGS, $SHOBJSUFFIX, $WINDOWSDEFPREFIX, $WINDOWSDEFSUFFIX.

Uses: $RCCOMSTR, $SHLINKCOMSTR.

msgfmt
This scons tool is a part of scons gettext toolset. It provides scons interface to
msgfmt(1) command, which generates binary message catalog (MO) from a textual
translation description (PO).

Sets: $MOSUFFIX, $MSGFMT, $MSGFMTCOM, $MSGFMTCOMSTR, $MSGFMTFLAGS, $POSUFFIX.

Uses: $LINGUAS_FILE.

msginit
This scons tool is a part of scons gettext toolset. It provides scons interface to
msginit(1) program, which creates new PO file, initializing the meta information with
values from user's environment (or options).

Sets: $MSGINIT, $MSGINITCOM, $MSGINITCOMSTR, $MSGINITFLAGS, $POAUTOINIT,
$POCREATE_ALIAS, $POSUFFIX, $POTSUFFIX, $_MSGINITLOCALE.

Uses: $LINGUAS_FILE, $POAUTOINIT, $POTDOMAIN.

msgmerge
This scons tool is a part of scons gettext toolset. It provides scons interface to
msgmerge(1) command, which merges two Uniform style .po files together.

Sets: $MSGMERGE, $MSGMERGECOM, $MSGMERGECOMSTR, $MSGMERGEFLAGS, $POSUFFIX, $POTSUFFIX,
$POUPDATE_ALIAS.

Uses: $LINGUAS_FILE, $POAUTOINIT, $POTDOMAIN.

mslib
Sets construction variables for the Microsoft mslib library archiver.

Sets: $AR, $ARCOM, $ARFLAGS, $LIBPREFIX, $LIBSUFFIX.

Uses: $ARCOMSTR.

mslink
Sets construction variables for the Microsoft linker.

Sets: $LDMODULE, $LDMODULECOM, $LDMODULEFLAGS, $LDMODULEPREFIX, $LDMODULESUFFIX,
$LIBDIRPREFIX, $LIBDIRSUFFIX, $LIBLINKPREFIX, $LIBLINKSUFFIX, $LINK, $LINKCOM,
$LINKFLAGS, $REGSVR, $REGSVRCOM, $REGSVRFLAGS, $SHLINK, $SHLINKCOM, $SHLINKFLAGS,
$WIN32DEFPREFIX, $WIN32DEFSUFFIX, $WIN32EXPPREFIX, $WIN32EXPSUFFIX, $WINDOWSDEFPREFIX,
$WINDOWSDEFSUFFIX, $WINDOWSEXPPREFIX, $WINDOWSEXPSUFFIX, $WINDOWSPROGMANIFESTPREFIX,
$WINDOWSPROGMANIFESTSUFFIX, $WINDOWSSHLIBMANIFESTPREFIX, $WINDOWSSHLIBMANIFESTSUFFIX,
$WINDOWS_INSERT_DEF.

Uses: $LDMODULECOMSTR, $LINKCOMSTR, $REGSVRCOMSTR, $SHLINKCOMSTR.

mssdk
Sets variables for Microsoft Platform SDK and/or Windows SDK. Note that unlike most
other Tool modules, mssdk does not set construction variables, but sets the
environment variables in the environment SCons uses to execute the Microsoft
toolchain: %INCLUDE%, %LIB%, %LIBPATH% and %PATH%.

Uses: $MSSDK_DIR, $MSSDK_VERSION, $MSVS_VERSION.

msvc
Sets construction variables for the Microsoft Visual C/C++ compiler.

Sets: $BUILDERS, $CC, $CCCOM, $CCFLAGS, $CCPCHFLAGS, $CCPDBFLAGS, $CFILESUFFIX,
$CFLAGS, $CPPDEFPREFIX, $CPPDEFSUFFIX, $CXX, $CXXCOM, $CXXFILESUFFIX, $CXXFLAGS,
$INCPREFIX, $INCSUFFIX, $OBJPREFIX, $OBJSUFFIX, $PCHCOM, $PCHPDBFLAGS, $RC, $RCCOM,
$RCFLAGS, $SHCC, $SHCCCOM, $SHCCFLAGS, $SHCFLAGS, $SHCXX, $SHCXXCOM, $SHCXXFLAGS,
$SHOBJPREFIX, $SHOBJSUFFIX.

Uses: $CCCOMSTR, $CXXCOMSTR, $PCH, $PCHSTOP, $PDB, $SHCCCOMSTR, $SHCXXCOMSTR.

msvs
Sets construction variables for Microsoft Visual Studio.

Sets: $MSVSBUILDCOM, $MSVSCLEANCOM, $MSVSENCODING, $MSVSPROJECTCOM, $MSVSREBUILDCOM,
$MSVSSCONS, $MSVSSCONSCOM, $MSVSSCONSCRIPT, $MSVSSCONSFLAGS, $MSVSSOLUTIONCOM.

mwcc
Sets construction variables for the Metrowerks CodeWarrior compiler.

Sets: $CC, $CCCOM, $CFILESUFFIX, $CPPDEFPREFIX, $CPPDEFSUFFIX, $CXX, $CXXCOM,
$CXXFILESUFFIX, $INCPREFIX, $INCSUFFIX, $MWCW_VERSION, $MWCW_VERSIONS, $SHCC,
$SHCCCOM, $SHCCFLAGS, $SHCFLAGS, $SHCXX, $SHCXXCOM, $SHCXXFLAGS.

Uses: $CCCOMSTR, $CXXCOMSTR, $SHCCCOMSTR, $SHCXXCOMSTR.

mwld
Sets construction variables for the Metrowerks CodeWarrior linker.

Sets: $AR, $ARCOM, $LIBDIRPREFIX, $LIBDIRSUFFIX, $LIBLINKPREFIX, $LIBLINKSUFFIX,
$LINK, $LINKCOM, $SHLINK, $SHLINKCOM, $SHLINKFLAGS.

nasm
Sets construction variables for the nasm Netwide Assembler.

Sets: $AS, $ASCOM, $ASFLAGS, $ASPPCOM, $ASPPFLAGS.

Uses: $ASCOMSTR, $ASPPCOMSTR.

packaging
A framework for building binary and source packages.

Packaging
Sets construction variables for the Package Builder.

pdf
Sets construction variables for the Portable Document Format builder.

Sets: $PDFPREFIX, $PDFSUFFIX.

pdflatex
Sets construction variables for the pdflatex utility.

Sets: $LATEXRETRIES, $PDFLATEX, $PDFLATEXCOM, $PDFLATEXFLAGS.

Uses: $PDFLATEXCOMSTR.

pdftex
Sets construction variables for the pdftex utility.

Sets: $LATEXRETRIES, $PDFLATEX, $PDFLATEXCOM, $PDFLATEXFLAGS, $PDFTEX, $PDFTEXCOM,
$PDFTEXFLAGS.

Uses: $PDFLATEXCOMSTR, $PDFTEXCOMSTR.

python
Loads the Python source scanner into the invoking environment. When loaded, the
scanner will attempt to find implicit dependencies for any Python source files in the
list of sources provided to an Action that uses this environment.

Available since scons 4.0..

qt
Sets construction variables for building Qt applications.

Sets: $QTDIR, $QT_AUTOSCAN, $QT_BINPATH, $QT_CPPPATH, $QT_LIB, $QT_LIBPATH, $QT_MOC,
$QT_MOCCXXPREFIX, $QT_MOCCXXSUFFIX, $QT_MOCFROMCXXCOM, $QT_MOCFROMCXXFLAGS,
$QT_MOCFROMHCOM, $QT_MOCFROMHFLAGS, $QT_MOCHPREFIX, $QT_MOCHSUFFIX, $QT_UIC,
$QT_UICCOM, $QT_UICDECLFLAGS, $QT_UICDECLPREFIX, $QT_UICDECLSUFFIX, $QT_UICIMPLFLAGS,
$QT_UICIMPLPREFIX, $QT_UICIMPLSUFFIX, $QT_UISUFFIX.

rmic
Sets construction variables for the rmic utility.

Sets: $JAVACLASSSUFFIX, $RMIC, $RMICCOM, $RMICFLAGS.

Uses: $RMICCOMSTR.

rpcgen
Sets construction variables for building with RPCGEN.

Sets: $RPCGEN, $RPCGENCLIENTFLAGS, $RPCGENFLAGS, $RPCGENHEADERFLAGS,
$RPCGENSERVICEFLAGS, $RPCGENXDRFLAGS.

sgiar
Sets construction variables for the SGI library archiver.

Sets: $AR, $ARCOMSTR, $ARFLAGS, $LIBPREFIX, $LIBSUFFIX, $SHLINK, $SHLINKFLAGS.

Uses: $ARCOMSTR, $SHLINKCOMSTR.

sgic++
Sets construction variables for the SGI C++ compiler.

Sets: $CXX, $CXXFLAGS, $SHCXX, $SHOBJSUFFIX.

sgicc
Sets construction variables for the SGI C compiler.

Sets: $CXX, $SHOBJSUFFIX.

sgilink
Sets construction variables for the SGI linker.

Sets: $LINK, $RPATHPREFIX, $RPATHSUFFIX, $SHLINKFLAGS.

sunar
Sets construction variables for the Sun library archiver.

Sets: $AR, $ARCOM, $ARFLAGS, $LIBPREFIX, $LIBSUFFIX.

Uses: $ARCOMSTR.

sunc++
Sets construction variables for the Sun C++ compiler.

Sets: $CXX, $CXXVERSION, $SHCXX, $SHCXXFLAGS, $SHOBJPREFIX, $SHOBJSUFFIX.

suncc
Sets construction variables for the Sun C compiler.

Sets: $CXX, $SHCCFLAGS, $SHOBJPREFIX, $SHOBJSUFFIX.

sunf77
Set construction variables for the Sun f77 Fortran compiler.

Sets: $F77, $FORTRAN, $SHF77, $SHF77FLAGS, $SHFORTRAN, $SHFORTRANFLAGS.

sunf90
Set construction variables for the Sun f90 Fortran compiler.

Sets: $F90, $FORTRAN, $SHF90, $SHF90FLAGS, $SHFORTRAN, $SHFORTRANFLAGS.

sunf95
Set construction variables for the Sun f95 Fortran compiler.

Sets: $F95, $FORTRAN, $SHF95, $SHF95FLAGS, $SHFORTRAN, $SHFORTRANFLAGS.

sunlink
Sets construction variables for the Sun linker.

Sets: $RPATHPREFIX, $RPATHSUFFIX, $SHLINKFLAGS.

swig
Sets construction variables for the SWIG interface generator.

Sets: $SWIG, $SWIGCFILESUFFIX, $SWIGCOM, $SWIGCXXFILESUFFIX, $SWIGDIRECTORSUFFIX,
$SWIGFLAGS, $SWIGINCPREFIX, $SWIGINCSUFFIX, $SWIGPATH, $SWIGVERSION, $_SWIGINCFLAGS.

Uses: $SWIGCOMSTR.

tar
Sets construction variables for the tar archiver.

Sets: $TAR, $TARCOM, $TARFLAGS, $TARSUFFIX.

Uses: $TARCOMSTR.

tex
Sets construction variables for the TeX formatter and typesetter.

Sets: $BIBTEX, $BIBTEXCOM, $BIBTEXFLAGS, $LATEX, $LATEXCOM, $LATEXFLAGS, $MAKEINDEX,
$MAKEINDEXCOM, $MAKEINDEXFLAGS, $TEX, $TEXCOM, $TEXFLAGS.

Uses: $BIBTEXCOMSTR, $LATEXCOMSTR, $MAKEINDEXCOMSTR, $TEXCOMSTR.

textfile
Set construction variables for the Textfile and Substfile builders.

Sets: $LINESEPARATOR, $SUBSTFILEPREFIX, $SUBSTFILESUFFIX, $TEXTFILEPREFIX,
$TEXTFILESUFFIX.

Uses: $SUBST_DICT.

tlib
Sets construction variables for the Borlan tib library archiver.

Sets: $AR, $ARCOM, $ARFLAGS, $LIBPREFIX, $LIBSUFFIX.

Uses: $ARCOMSTR.

xgettext
This scons tool is a part of scons gettext toolset. It provides scons interface to
xgettext(1) program, which extracts internationalized messages from source code. The
tool provides POTUpdate builder to make PO Template files.

Sets: $POTSUFFIX, $POTUPDATE_ALIAS, $XGETTEXTCOM, $XGETTEXTCOMSTR, $XGETTEXTFLAGS,
$XGETTEXTFROM, $XGETTEXTFROMPREFIX, $XGETTEXTFROMSUFFIX, $XGETTEXTPATH,
$XGETTEXTPATHPREFIX, $XGETTEXTPATHSUFFIX, $_XGETTEXTDOMAIN, $_XGETTEXTFROMFLAGS,
$_XGETTEXTPATHFLAGS.

Uses: $POTDOMAIN.

yacc
Sets construction variables for the yacc parse generator.

Sets: $YACC, $YACCCOM, $YACCFLAGS, $YACCHFILESUFFIX, $YACCHXXFILESUFFIX,
$YACCVCGFILESUFFIX.

Uses: $YACCCOMSTR.

zip
Sets construction variables for the zip archiver.

Sets: $ZIP, $ZIPCOM, $ZIPCOMPRESSION, $ZIPFLAGS, $ZIPSUFFIX.

Uses: $ZIPCOMSTR.

Builder Methods
You tell scons what to build by calling Builders, functions which know to take a
particular action to produce a particular result type when given source files of a
particular type. scons defines a number of builders, and you can also write your own.
Builders are attached to a construction environment as methods, and the available builder
methods are listed as key-value pairs in the BUILDERS attribute of the construction
environment. The available builders can be displayed like this for debugging purposes:

print("Builders:", list(env['BUILDERS']))

Builder methods always take two arguments: target (a target or a list of targets to be
built) and source (a source or list of sources to be used as input when building),
although in some circumstances, the target argument can actually be omitted (see below).
Builder methods also take a variety of keyword arguments, described below.

Because long lists of file names can lead to a lot of quoting, scons supplies a Split
global function and a same-named environment method that splits a single string into a
list, using strings of white-space characters as the delimiter. (similar to the Python
string split method, but succeeds even if the input isn't a string.)

The target and source arguments to a builder method can be specified either as positional
arguments, in which case the target comes first, or as keyword arguments, using target=
and source=. The following are equivalent examples of calling the Program builder method:

env.Program('bar', ['bar.c', 'foo.c'])
env.Program('bar', Split('bar.c foo.c'))
env.Program('bar', env.Split('bar.c foo.c'))
env.Program(source=['bar.c', 'foo.c'], target='bar')
env.Program(target='bar', source=Split('bar.c foo.c'))
env.Program(target='bar', source=env.Split('bar.c foo.c'))
env.Program('bar', source='bar.c foo.c'.split())

Python follows the POSIX pathname convention for path strings: if a string begins with the
operating system pathname separator (on Windows both the slash and backslash separator
work, and any leading drive specifier is ignored for the determination) it is considered
an absolute path, otherwise it is a relative path. If the path string contains no
separator characters, it is searched for as a file in the current directory. If it
contains separator characters, the search follows down from the starting point, which is
the top of the directory tree for an absolute path and the current directory for a
relative path.

scons recognizes a third way to specify path strings: if the string begins with the #
character it is top-relative - it works like a relative path but the search follows down
from the directory containing the top-level SConstruct rather than from the current
directory. The # is allowed to be followed by a pathname separator, which is ignored if
found in that position. Top-relative paths only work in places where scons will interpret
the path (see some examples below). To be used in other contexts the string will need to
be converted to a relative or absolute path first.

Target and source pathnames can be absolute, relative, or top-relative. Relative pathnames
are searched considering the directory of the SConscript file currently being processed as
the "current directory".

Examples:

# The comments describing the targets that will be built
# assume these calls are in a SConscript file in the
# a subdirectory named "subdir".

# Builds the program "subdir/foo" from "subdir/foo.c":
env.Program('foo', 'foo.c')

# Builds the program "/tmp/bar" from "subdir/bar.c":
env.Program('/tmp/bar', 'bar.c')

# An initial '#' or '#/' are equivalent; the following
# calls build the programs "foo" and "bar" (in the
# top-level SConstruct directory) from "subdir/foo.c" and
# "subdir/bar.c", respectively:
env.Program('#foo', 'foo.c')
env.Program('#/bar', 'bar.c')

# Builds the program "other/foo" (relative to the top-level
# SConstruct directory) from "subdir/foo.c":
env.Program('#other/foo', 'foo.c')

# This will not work, only SCons interfaces understand '#',
# os.path.exists is pure Python:
if os.path.exists('#inc/foo.h'):
env.Append(CPPPATH='#inc')

When the target shares the same base name as the source and only the suffix varies, and if
the builder method has a suffix defined for the target file type, then the target argument
may be omitted completely, and scons will deduce the target file name from the source file
name. The following examples all build the executable program bar (on POSIX systems) or
bar.exe (on Windows systems) from the bar.c source file:

env.Program(target='bar', source='bar.c')
env.Program('bar', source='bar.c')
env.Program(source='bar.c')
env.Program('bar.c')

As a convenience, a srcdir keyword argument may be specified when calling a Builder. When
specified, all source file strings that are not absolute paths or top-relative paths will
be interpreted relative to the specified srcdir. The following example will build the
build/prog (or build/prog.exe on Windows) program from the files src/f1.c and src/f2.c:

env.Program('build/prog', ['f1.c', 'f2.c'], srcdir='src')

It is possible to override (replace or add) construction variables when calling a builder
method by passing them as keyword arguments. These overrides will only be in effect when
building that target, and will not affect other parts of the build. For example, if you
want to specify some libraries needed by just one program:

env.Program('hello', 'hello.c', LIBS=['gl', 'glut'])

or generate a shared library with a non-standard suffix:

env.SharedLibrary('word', 'word.cpp',
SHLIBSUFFIX='.ocx',
LIBSUFFIXES=['.ocx'])

Note that both the $SHLIBSUFFIX and $LIBSUFFIXES variables must be set if you want scons
to search automatically for dependencies on the non-standard library names; see the
descriptions below of these variables for more information.

It is also possible to use the parse_flags keyword argument in an override, to merge
command-line style arguments into the appropriate construction variables (see
env.MergeFlags).

env = Program('hello', 'hello.c', parse_flags='-Iinclude -DEBUG -lm')

This example adds 'include' to CPPPATH, 'EBUG' to CPPDEFINES, and 'm' to LIBS.

Although the builder methods defined by scons are, in fact, methods of a construction
environment object, they may also be called without an explicit environment:

Program('hello', 'hello.c')
SharedLibrary('word', 'word.cpp')

In this case, the methods are called internally using a default construction environment
that consists of the tools and values that scons has determined are appropriate for the
local system.

Builder methods that can be called without an explicit environment may be called from
custom Python modules that you import into an SConscript file by adding the following to
the Python module:

from SCons.Script import *

All builder methods return a list-like object containing Nodes that will be built. A Node
is an internal SCons object which represents build targets or sources.

The returned Node-list object can be passed to other builder methods as source(s) or
passed to any SCons function or method where a filename would normally be accepted. For
example, if it were necessary to add a specific preprocessor define when compiling one
specific object file:

bar_obj_list = env.StaticObject('bar.c', CPPDEFINES='-DBAR')
env.Program(source=['foo.c', bar_obj_list, 'main.c'])

Using a Node in this way makes for a more portable build by avoiding having to specify a
platform-specific object suffix when calling the Program builder method.

Builder calls will automatically "flatten" lists passed as source and target, so they are
free to contain elements which are themselves lists, such as bar_obj_list returned by the
StaticObject call above. If you need to manipulate a list of lists returned by builders
directly in Python code, you can either build a new list by hand:

foo = Object('foo.c')
bar = Object('bar.c')
objects = ['begin.o'] + foo + ['middle.o'] + bar + ['end.o']
for obj in objects:
print(str(obj))

Or you can use the Flatten function supplied by scons to create a list containing just the
Nodes, which may be more convenient:

foo = Object('foo.c')
bar = Object('bar.c')
objects = Flatten(['begin.o', foo, 'middle.o', bar, 'end.o'])
for obj in objects:
print(str(obj))

SCons builder calls return a list-like object, not an actual Python list, so it is not
appropriate to use the Python add operator (+ or +=) to append builder results to a Python
list. Because the list and the object are different types, Python will not update the
original list in place, but will instead create a new Node-list object containing the
concatenation of the list elements and the builder results. This will cause problems for
any other Python variables in your SCons configuration that still hold on to a reference
to the original list. Instead, use the Python list extend method to make sure the list is
updated in-place. Example:

object_files = []

# Do NOT use += here:
# object_files += Object('bar.c')
#
# It will not update the object_files list in place.
#
# Instead, use the list extend method:
object_files.extend(Object('bar.c'))

The path name for a Node's file may be used by passing the Node to Python's builtin str
function:

bar_obj_list = env.StaticObject('bar.c', CPPDEFINES='-DBAR')
print("The path to bar_obj is:", str(bar_obj_list[0]))

Note again that because the Builder call returns a list, we have to access the first
element in the list ((bar_obj_list[0])) to get at the Node that actually represents the
object file.

Builder calls support a chdir keyword argument that specifies that the Builder's action(s)
should be executed after changing directory. If the chdir argument is a string or a
directory Node, scons will change to the specified directory. If the chdir is not a string
or Node and is non-zero, then scons will change to the target file's directory.

# scons will change to the "sub" subdirectory
# before executing the "cp" command.
env.Command('sub/dir/foo.out', 'sub/dir/foo.in',
"cp dir/foo.in dir/foo.out",
chdir='sub')

# Because chdir is not a string, scons will change to the
# target's directory ("sub/dir") before executing the
# "cp" command.
env.Command('sub/dir/foo.out', 'sub/dir/foo.in',
"cp foo.in foo.out",
chdir=1)

Note that SCons will not automatically modify its expansion of construction variables like
$TARGET and $SOURCE when using the chdir keyword argument--that is, the expanded file
names will still be relative to the top-level directory where SConstruct was found, and
consequently incorrect relative to the chdir directory. If you use the chdir keyword
argument, you will typically need to supply a different command line using expansions like
${TARGET.file} and ${SOURCE.file} to use just the filename portion of the targets and
source.

scons predefines the following builder methods. Depending on the setup of a particular
construction environment and on the type and software installation status of the
underlying system, not all builders may be available to that construction environment.

CFile(), env.CFile()
Builds a C source file given a lex (.l) or yacc (.y) input file. The suffix specified
by the $CFILESUFFIX construction variable (.c by default) is automatically added to
the target if it is not already present. Example:

# builds foo.c
env.CFile(target = 'foo.c', source = 'foo.l')
# builds bar.c
env.CFile(target = 'bar', source = 'bar.y')

Command(), env.Command()
The Command "Builder" is actually a function that looks like a Builder, but takes a
required third argument, which is the action to take to construct the target from the
source, used for "one-off" builds where a full builder is not needed. Thus it does not
follow the builder calling rules described at the start of this section. See instead
the Command function description for the calling syntax and details.

CompilationDatabase(), env.CompilationDatabase()
The CompilationDatabase builder writes a JSON formatted compilation database according
to the LLVM specification[1] which is consumed by a number of clang tools, editors,
and other tools.

If you don't specify any files, the builder will default to compile_commands.json.

If you specify a single file as below

env.CompilationDatabase('my_output.json')

SCons will automatically use that as the target file. If you specify more than one
source, the source list will be ignored.

You should not specify source files. The CompilationDatabase builder instruments SCons
to collect them from all the C, C++, assembly source/target pairs.

NOTE: You must load the compilation_db tool prior to specifying any part of your build
or some source/target files will not show up in your output file.

Available since scons 4.0.

CXXFile(), env.CXXFile()
Builds a C++ source file given a lex (.ll) or yacc (.yy) input file. The suffix
specified by the $CXXFILESUFFIX construction variable (.cc by default) is
automatically added to the target if it is not already present. Example:

# builds foo.cc
env.CXXFile(target = 'foo.cc', source = 'foo.ll')
# builds bar.cc
env.CXXFile(target = 'bar', source = 'bar.yy')

DocbookEpub(), env.DocbookEpub()
A pseudo-Builder, providing a Docbook toolchain for EPUB output.

env = Environment(tools=['docbook'])
env.DocbookEpub('manual.epub', 'manual.xml')

or simply

env = Environment(tools=['docbook'])
env.DocbookEpub('manual')

DocbookHtml(), env.DocbookHtml()
A pseudo-Builder, providing a Docbook toolchain for HTML output.

env = Environment(tools=['docbook'])
env.DocbookHtml('manual.html', 'manual.xml')

or simply

env = Environment(tools=['docbook'])
env.DocbookHtml('manual')

DocbookHtmlChunked(), env.DocbookHtmlChunked()
A pseudo-Builder, providing a Docbook toolchain for chunked HTML output. It supports
the base.dir parameter. The chunkfast.xsl file (requires "EXSLT") is used as the
default stylesheet. Basic syntax:

env = Environment(tools=['docbook'])
env.DocbookHtmlChunked('manual')

where manual.xml is the input file.

If you use the root.filename parameter in your own stylesheets you have to specify the
new target name. This ensures that the dependencies get correct, especially for the
cleanup via “scons -c”:

env = Environment(tools=['docbook'])
env.DocbookHtmlChunked('mymanual.html', 'manual', xsl='htmlchunk.xsl')

Some basic support for the base.dir is provided. You can add the base_dir keyword to
your Builder call, and the given prefix gets prepended to all the created filenames:

env = Environment(tools=['docbook'])
env.DocbookHtmlChunked('manual', xsl='htmlchunk.xsl', base_dir='output/')

Make sure that you don't forget the trailing slash for the base folder, else your
files get renamed only!

DocbookHtmlhelp(), env.DocbookHtmlhelp()
A pseudo-Builder, providing a Docbook toolchain for HTMLHELP output. Its basic syntax
is:

env = Environment(tools=['docbook'])
env.DocbookHtmlhelp('manual')

where manual.xml is the input file.

If you use the root.filename parameter in your own stylesheets you have to specify the
new target name. This ensures that the dependencies get correct, especially for the
cleanup via “scons -c”:

env = Environment(tools=['docbook'])
env.DocbookHtmlhelp('mymanual.html', 'manual', xsl='htmlhelp.xsl')

Some basic support for the base.dir parameter is provided. You can add the base_dir
keyword to your Builder call, and the given prefix gets prepended to all the created
filenames:

env = Environment(tools=['docbook'])
env.DocbookHtmlhelp('manual', xsl='htmlhelp.xsl', base_dir='output/')

Make sure that you don't forget the trailing slash for the base folder, else your
files get renamed only!

DocbookMan(), env.DocbookMan()
A pseudo-Builder, providing a Docbook toolchain for Man page output. Its basic syntax
is:

env = Environment(tools=['docbook'])
env.DocbookMan('manual')

where manual.xml is the input file. Note, that you can specify a target name, but the
actual output names are automatically set from the refname entries in your XML source.

DocbookPdf(), env.DocbookPdf()
A pseudo-Builder, providing a Docbook toolchain for PDF output.

env = Environment(tools=['docbook'])
env.DocbookPdf('manual.pdf', 'manual.xml')

or simply

env = Environment(tools=['docbook'])
env.DocbookPdf('manual')

DocbookSlidesHtml(), env.DocbookSlidesHtml()
A pseudo-Builder, providing a Docbook toolchain for HTML slides output.

env = Environment(tools=['docbook'])
env.DocbookSlidesHtml('manual')

If you use the titlefoil.html parameter in your own stylesheets you have to give the
new target name. This ensures that the dependencies get correct, especially for the
cleanup via “scons -c”:

env = Environment(tools=['docbook'])
env.DocbookSlidesHtml('mymanual.html','manual', xsl='slideshtml.xsl')

Some basic support for the base.dir parameter is provided. You can add the base_dir
keyword to your Builder call, and the given prefix gets prepended to all the created
filenames:

env = Environment(tools=['docbook'])
env.DocbookSlidesHtml('manual', xsl='slideshtml.xsl', base_dir='output/')

Make sure that you don't forget the trailing slash for the base folder, else your
files get renamed only!

DocbookSlidesPdf(), env.DocbookSlidesPdf()
A pseudo-Builder, providing a Docbook toolchain for PDF slides output.

env = Environment(tools=['docbook'])
env.DocbookSlidesPdf('manual.pdf', 'manual.xml')

or simply

env = Environment(tools=['docbook'])
env.DocbookSlidesPdf('manual')

DocbookXInclude(), env.DocbookXInclude()
A pseudo-Builder, for resolving XIncludes in a separate processing step.

env = Environment(tools=['docbook'])
env.DocbookXInclude('manual_xincluded.xml', 'manual.xml')

DocbookXslt(), env.DocbookXslt()
A pseudo-Builder, applying a given XSL transformation to the input file.

env = Environment(tools=['docbook'])
env.DocbookXslt('manual_transformed.xml', 'manual.xml', xsl='transform.xslt')

Note, that this builder requires the xsl parameter to be set.

DVI(), env.DVI()
Builds a .dvi file from a .tex, .ltx or .latex input file. If the source file suffix
is .tex, scons will examine the contents of the file; if the string \documentclass or
\documentstyle is found, the file is assumed to be a LaTeX file and the target is
built by invoking the $LATEXCOM command line; otherwise, the $TEXCOM command line is
used. If the file is a LaTeX file, the DVI builder method will also examine the
contents of the .aux file and invoke the $BIBTEX command line if the string bibdata is
found, start $MAKEINDEX to generate an index if a .ind file is found and will examine
the contents .log file and re-run the $LATEXCOM command if the log file says it is
necessary.

The suffix .dvi (hard-coded within TeX itself) is automatically added to the target if
it is not already present. Examples:

# builds from aaa.tex
env.DVI(target = 'aaa.dvi', source = 'aaa.tex')
# builds bbb.dvi
env.DVI(target = 'bbb', source = 'bbb.ltx')
# builds from ccc.latex
env.DVI(target = 'ccc.dvi', source = 'ccc.latex')

Gs(), env.Gs()
A Builder for explicitly calling the gs executable. Depending on the underlying OS,
the different names gs, gsos2 and gswin32c are tried.

env = Environment(tools=['gs'])
env.Gs('cover.jpg','scons-scons.pdf',
GSFLAGS='-dNOPAUSE -dBATCH -sDEVICE=jpeg -dFirstPage=1 -dLastPage=1 -q')
)

Install(), env.Install()
Installs one or more source files or directories in the specified target, which must
be a directory. The names of the specified source files or directories remain the same
within the destination directory. The sources may be given as a string or as a node
returned by a builder.

env.Install(target='/usr/local/bin', source=['foo', 'bar'])

Note that if target paths chosen for the Install builder (and the related InstallAs
and InstallVersionedLib builders) are outside the project tree, such as in the example
above, they may not be selected for "building" by default, since in the absence of
other instructions scons builds targets that are underneath the top directory (the
directory that contains the SConstruct file, usually the current directory). Use
command line targets or the Default function in this case.

If the --install-sandbox command line option is given, the target directory will be
prefixed by the directory path specified. This is useful to test installs without
installing to a "live" location in the system.

See also FindInstalledFiles. For more thoughts on installation, see the User Guide
(particularly the section on Command-Line Targets and the chapters on Installing Files
and on Alias Targets).

InstallAs(), env.InstallAs()
Installs one or more source files or directories to specific names, allowing changing
a file or directory name as part of the installation. It is an error if the target and
source arguments list different numbers of files or directories.

env.InstallAs(target='/usr/local/bin/foo',
source='foo_debug')
env.InstallAs(target=['../lib/libfoo.a', '../lib/libbar.a'],
source=['libFOO.a', 'libBAR.a'])

See the note under Install.

InstallVersionedLib(), env.InstallVersionedLib()
Installs a versioned shared library. The symlinks appropriate to the architecture will
be generated based on symlinks of the source library.

env.InstallVersionedLib(target='/usr/local/bin/foo',
source='libxyz.1.5.2.so')

See the note under Install.

Jar(), env.Jar()
Builds a Java archive (.jar) file from the specified list of sources. Any directories
in the source list will be searched for .class files). Any .java files in the source
list will be compiled to .class files by calling the Java Builder.

If the $JARCHDIR value is set, the jar command will change to the specified directory
using the -C option. If $JARCHDIR is not set explicitly, SCons will use the top of any
subdirectory tree in which Java .class were built by the Java Builder.

If the contents any of the source files begin with the string Manifest-Version, the
file is assumed to be a manifest and is passed to the jar command with the m option
set.

env.Jar(target = 'foo.jar', source = 'classes')

env.Jar(target = 'bar.jar',
source = ['bar1.java', 'bar2.java'])

Java(), env.Java()
Builds one or more Java class files. The sources may be any combination of explicit
.java files, or directory trees which will be scanned for .java files.

SCons will parse each source .java file to find the classes (including inner classes)
defined within that file, and from that figure out the target .class files that will
be created. The class files will be placed underneath the specified target directory.

SCons will also search each Java file for the Java package name, which it assumes can
be found on a line beginning with the string package in the first column; the
resulting .class files will be placed in a directory reflecting the specified package
name. For example, the file Foo.java defining a single public Foo class and containing
a package name of sub.dir will generate a corresponding sub/dir/Foo.class class file.

Examples:

env.Java(target = 'classes', source = 'src')
env.Java(target = 'classes', source = ['src1', 'src2'])
env.Java(target = 'classes', source = ['File1.java', 'File2.java'])

Java source files can use the native encoding for the underlying OS. Since SCons
compiles in simple ASCII mode by default, the compiler will generate warnings about
unmappable characters, which may lead to errors as the file is processed further. In
this case, the user must specify the LANG environment variable to tell the compiler
what encoding is used. For portibility, it's best if the encoding is hard-coded so
that the compile will work if it is done on a system with a different encoding.

env = Environment()
env['ENV']['LANG'] = 'en_GB.UTF-8'

JavaH(), env.JavaH()
Builds C header and source files for implementing Java native methods. The target can
be either a directory in which the header files will be written, or a header file name
which will contain all of the definitions. The source can be the names of .class
files, the names of .java files to be compiled into .class files by calling the Java
builder method, or the objects returned from the Java builder method.

If the construction variable $JAVACLASSDIR is set, either in the environment or in the
call to the JavaH builder method itself, then the value of the variable will be
stripped from the beginning of any .class file names.

Examples:

# builds java_native.h
classes = env.Java(target="classdir", source="src")
env.JavaH(target="java_native.h", source=classes)

# builds include/package_foo.h and include/package_bar.h
env.JavaH(target="include", source=["package/foo.class", "package/bar.class"])

# builds export/foo.h and export/bar.h
env.JavaH(
target="export",
source=["classes/foo.class", "classes/bar.class"],
JAVACLASSDIR="classes",
)

Library(), env.Library()
A synonym for the StaticLibrary builder method.

LoadableModule(), env.LoadableModule()
On most systems, this is the same as SharedLibrary. On Mac OS X (Darwin) platforms,
this creates a loadable module bundle.

M4(), env.M4()
Builds an output file from an M4 input file. This uses a default $M4FLAGS value of -E,
which considers all warnings to be fatal and stops on the first warning when using the
GNU version of m4. Example:

env.M4(target = 'foo.c', source = 'foo.c.m4')

Moc(), env.Moc()
Builds an output file from a moc input file. Moc input files are either header files
or cxx files. This builder is only available after using the tool 'qt'. See the $QTDIR
variable for more information. Example:

env.Moc('foo.h') # generates moc_foo.cc
env.Moc('foo.cpp') # generates foo.moc

MOFiles(), env.MOFiles()
This builder belongs to msgfmt tool. The builder compiles PO files to MO files.

Example 1. Create pl.mo and en.mo by compiling pl.po and en.po:

# ...
env.MOFiles(['pl', 'en'])

Example 2. Compile files for languages defined in LINGUAS file:

# ...
env.MOFiles(LINGUAS_FILE = 1)

Example 3. Create pl.mo and en.mo by compiling pl.po and en.po plus files for
languages defined in LINGUAS file:

# ...
env.MOFiles(['pl', 'en'], LINGUAS_FILE = 1)

Example 4. Compile files for languages defined in LINGUAS file (another version):

# ...
env['LINGUAS_FILE'] = 1
env.MOFiles()

MSVSProject(), env.MSVSProject()
Builds a Microsoft Visual Studio project file, and by default builds a solution file
as well.

This builds a Visual Studio project file, based on the version of Visual Studio that
is configured (either the latest installed version, or the version specified by
$MSVS_VERSION in the Environment constructor). For Visual Studio 6, it will generate a
.dsp file. For Visual Studio 7, 8, and 9, it will generate a .vcproj file. For Visual
Studio 10 and later, it will generate a .vcxproj file.

By default, this also generates a solution file for the specified project, a .dsw file
for Visual Studio 6 or a .sln file for Visual Studio 7 and later. This behavior may be
disabled by specifying auto_build_solution=0 when you call MSVSProject, in which case
you presumably want to build the solution file(s) by calling the MSVSSolution Builder
(see below).

The MSVSProject builder takes several lists of filenames to be placed into the project
file. These are currently limited to srcs, incs, localincs, resources, and misc. These
are pretty self-explanatory, but it should be noted that these lists are added to the
$SOURCES construction variable as strings, NOT as SCons File Nodes. This is because
they represent file names to be added to the project file, not the source files used
to build the project file.

The above filename lists are all optional, although at least one must be specified for
the resulting project file to be non-empty.

In addition to the above lists of values, the following values may be specified:

target
The name of the target .dsp or .vcproj file. The correct suffix for the version of
Visual Studio must be used, but the $MSVSPROJECTSUFFIX construction variable will
be defined to the correct value (see example below).

variant
The name of this particular variant. For Visual Studio 7 projects, this can also
be a list of variant names. These are typically things like "Debug" or "Release",
but really can be anything you want. For Visual Studio 7 projects, they may also
specify a target platform separated from the variant name by a | (vertical pipe)
character: Debug|Xbox. The default target platform is Win32. Multiple calls to
MSVSProject with different variants are allowed; all variants will be added to the
project file with their appropriate build targets and sources.

cmdargs
Additional command line arguments for the different variants. The number of
cmdargs entries must match the number of variant entries, or be empty (not
specified). If you give only one, it will automatically be propagated to all
variants.

cppdefines
Preprocessor definitions for the different variants. The number of cppdefines
entries must match the number of variant entries, or be empty (not specified). If
you give only one, it will automatically be propagated to all variants. If you
don't give this parameter, SCons will use the invoking environment's CPPDEFINES
entry for all variants.

cppflags
Compiler flags for the different variants. If a /std:c++ flag is found then
/Zc:__cplusplus is appended to the flags if not already found, this ensures that
intellisense uses the /std:c++ switch. The number of cppflags entries must match
the number of variant entries, or be empty (not specified). If you give only one,
it will automatically be propagated to all variants. If you don't give this
parameter, SCons will combine the invoking environment's CCFLAGS, CXXFLAGS,
CPPFLAGS entries for all variants.

cpppaths
Compiler include paths for the different variants. The number of cpppaths entries
must match the number of variant entries, or be empty (not specified). If you give
only one, it will automatically be propagated to all variants. If you don't give
this parameter, SCons will use the invoking environment's CPPPATH entry for all
variants.

buildtarget
An optional string, node, or list of strings or nodes (one per build variant), to
tell the Visual Studio debugger what output target to use in what build variant.
The number of buildtarget entries must match the number of variant entries.

runfile
The name of the file that Visual Studio 7 and later will run and debug. This
appears as the value of the Output field in the resulting Visual Studio project
file. If this is not specified, the default is the same as the specified
buildtarget value.

Note that because SCons always executes its build commands from the directory in which
the SConstruct file is located, if you generate a project file in a different
directory than the SConstruct directory, users will not be able to double-click on the
file name in compilation error messages displayed in the Visual Studio console output
window. This can be remedied by adding the Visual C/C++ /FC compiler option to the
$CCFLAGS variable so that the compiler will print the full path name of any files that
cause compilation errors.

Example usage:

barsrcs = ['bar.cpp']
barincs = ['bar.h']
barlocalincs = ['StdAfx.h']
barresources = ['bar.rc','resource.h']
barmisc = ['bar_readme.txt']

dll = env.SharedLibrary(target='bar.dll',
source=barsrcs)
buildtarget = [s for s in dll if str(s).endswith('dll')]
env.MSVSProject(target='Bar' + env['MSVSPROJECTSUFFIX'],
srcs=barsrcs,
incs=barincs,
localincs=barlocalincs,
resources=barresources,
misc=barmisc,
buildtarget=buildtarget,
variant='Release')

Starting with version 2.4 of SCons it is also possible to specify the optional
argument DebugSettings, which creates files for debugging under Visual Studio:

DebugSettings
A dictionary of debug settings that get written to the .vcproj.user or the
.vcxproj.user file, depending on the version installed. As it is done for cmdargs
(see above), you can specify a DebugSettings dictionary per variant. If you give
only one, it will be propagated to all variants.

Currently, only Visual Studio v9.0 and Visual Studio version v11 are implemented, for
other versions no file is generated. To generate the user file, you just need to add a
DebugSettings dictionary to the environment with the right parameters for your MSVS
version. If the dictionary is empty, or does not contain any good value, no file will
be generated.

Following is a more contrived example, involving the setup of a project for variants
and DebugSettings:

# Assuming you store your defaults in a file
vars = Variables('variables.py')
msvcver = vars.args.get('vc', '9')

# Check command args to force one Microsoft Visual Studio version
if msvcver == '9' or msvcver == '11':
env = Environment(MSVC_VERSION=msvcver+'.0', MSVC_BATCH=False)
else:
env = Environment()

AddOption('--userfile', action='store_true', dest='userfile', default=False,
help="Create Visual Studio Project user file")

#
# 1. Configure your Debug Setting dictionary with options you want in the list
# of allowed options, for instance if you want to create a user file to launch
# a specific application for testing your dll with Microsoft Visual Studio 2008 (v9):
#
V9DebugSettings = {
'Command':'c:\\myapp\\using\\thisdll.exe',
'WorkingDirectory': 'c:\\myapp\\using\\',
'CommandArguments': '-p password',
# 'Attach':'false',
# 'DebuggerType':'3',
# 'Remote':'1',
# 'RemoteMachine': None,
# 'RemoteCommand': None,
# 'HttpUrl': None,
# 'PDBPath': None,
# 'SQLDebugging': None,
# 'Environment': '',
# 'EnvironmentMerge':'true',
# 'DebuggerFlavor': None,
# 'MPIRunCommand': None,
# 'MPIRunArguments': None,
# 'MPIRunWorkingDirectory': None,
# 'ApplicationCommand': None,
# 'ApplicationArguments': None,
# 'ShimCommand': None,
# 'MPIAcceptMode': None,
# 'MPIAcceptFilter': None,
}

#
# 2. Because there are a lot of different options depending on the Microsoft
# Visual Studio version, if you use more than one version you have to
# define a dictionary per version, for instance if you want to create a user
# file to launch a specific application for testing your dll with Microsoft
# Visual Studio 2012 (v11):
#
V10DebugSettings = {
'LocalDebuggerCommand': 'c:\\myapp\\using\\thisdll.exe',
'LocalDebuggerWorkingDirectory': 'c:\\myapp\\using\\',
'LocalDebuggerCommandArguments': '-p password',
# 'LocalDebuggerEnvironment': None,
# 'DebuggerFlavor': 'WindowsLocalDebugger',
# 'LocalDebuggerAttach': None,
# 'LocalDebuggerDebuggerType': None,
# 'LocalDebuggerMergeEnvironment': None,
# 'LocalDebuggerSQLDebugging': None,
# 'RemoteDebuggerCommand': None,
# 'RemoteDebuggerCommandArguments': None,
# 'RemoteDebuggerWorkingDirectory': None,
# 'RemoteDebuggerServerName': None,
# 'RemoteDebuggerConnection': None,
# 'RemoteDebuggerDebuggerType': None,
# 'RemoteDebuggerAttach': None,
# 'RemoteDebuggerSQLDebugging': None,
# 'DeploymentDirectory': None,
# 'AdditionalFiles': None,
# 'RemoteDebuggerDeployDebugCppRuntime': None,
# 'WebBrowserDebuggerHttpUrl': None,
# 'WebBrowserDebuggerDebuggerType': None,
# 'WebServiceDebuggerHttpUrl': None,
# 'WebServiceDebuggerDebuggerType': None,
# 'WebServiceDebuggerSQLDebugging': None,
}

#
# 3. Select the dictionary you want depending on the version of visual Studio
# Files you want to generate.
#
if not env.GetOption('userfile'):
dbgSettings = None
elif env.get('MSVC_VERSION', None) == '9.0':
dbgSettings = V9DebugSettings
elif env.get('MSVC_VERSION', None) == '11.0':
dbgSettings = V10DebugSettings
else:
dbgSettings = None

#
# 4. Add the dictionary to the DebugSettings keyword.
#
barsrcs = ['bar.cpp', 'dllmain.cpp', 'stdafx.cpp']
barincs = ['targetver.h']
barlocalincs = ['StdAfx.h']
barresources = ['bar.rc','resource.h']
barmisc = ['ReadMe.txt']

dll = env.SharedLibrary(target='bar.dll',
source=barsrcs)

env.MSVSProject(target='Bar' + env['MSVSPROJECTSUFFIX'],
srcs=barsrcs,
incs=barincs,
localincs=barlocalincs,
resources=barresources,
misc=barmisc,
buildtarget=[dll[0]] * 2,
variant=('Debug|Win32', 'Release|Win32'),
cmdargs='vc=%s' % msvcver,
DebugSettings=(dbgSettings, {}))

MSVSSolution(), env.MSVSSolution()
Builds a Microsoft Visual Studio solution file.

This builds a Visual Studio solution file, based on the version of Visual Studio that
is configured (either the latest installed version, or the version specified by
$MSVS_VERSION in the construction environment). For Visual Studio 6, it will generate
a .dsw file. For Visual Studio 7 (.NET), it will generate a .sln file.

The following values must be specified:

target
The name of the target .dsw or .sln file. The correct suffix for the version of
Visual Studio must be used, but the value $MSVSSOLUTIONSUFFIX will be defined to
the correct value (see example below).

variant
The name of this particular variant, or a list of variant names (the latter is
only supported for MSVS 7 solutions). These are typically things like "Debug" or
"Release", but really can be anything you want. For MSVS 7 they may also specify
target platform, like this "Debug|Xbox". Default platform is Win32.

projects
A list of project file names, or Project nodes returned by calls to the
MSVSProject Builder, to be placed into the solution file. It should be noted that
these file names are NOT added to the $SOURCES environment variable in form of
files, but rather as strings. This is because they represent file names to be
added to the solution file, not the source files used to build the solution file.

Example Usage:

env.MSVSSolution(
target="Bar" + env["MSVSSOLUTIONSUFFIX"],
projects=["bar" + env["MSVSPROJECTSUFFIX"]],
variant="Release",
)

Object(), env.Object()
A synonym for the StaticObject builder method.

Package(), env.Package()
Builds a Binary Package of the given source files.

env.Package(source = FindInstalledFiles())

Builds software distribution packages. Packages consist of files to install and
packaging information. The former may be specified with the source parameter and may
be left out, in which case the FindInstalledFiles function will collect all files that
have an Install or InstallAs Builder attached. If the target is not specified it will
be deduced from additional information given to this Builder.

The packaging information is specified with the help of construction variables
documented below. This information is called a tag to stress that some of them can
also be attached to files with the Tag function. The mandatory ones will complain if
they were not specified. They vary depending on chosen target packager.

The target packager may be selected with the "PACKAGETYPE" command line option or with
the $PACKAGETYPE construction variable. Currently the following packagers available:
msi - Microsoft Installer
rpm - RPM Package Manger
ipkg - Itsy Package Management System
tarbz2 - bzip2 compressed tar
targz - gzip compressed tar
tarxz - xz compressed tar
zip - zip file
src_tarbz2 - bzip2 compressed tar source
src_targz - gzip compressed tar source
src_tarxz - xz compressed tar source
src_zip - zip file source
An updated list is always available under the package_type option when running scons
--help on a project that has packaging activated.

env = Environment(tools=["default", "packaging"])
env.Install("/bin/", "my_program")
env.Package(
NAME="foo",
VERSION="1.2.3",
PACKAGEVERSION=0,
PACKAGETYPE="rpm",
LICENSE="gpl",
SUMMARY="balalalalal",
DESCRIPTION="this should be really really long",
X_RPM_GROUP="Application/fu",
SOURCE_URL="http://foo.org/foo-1.2.3.tar.gz",
)

PCH(), env.PCH()
Builds a Microsoft Visual C++ precompiled header. Calling this builder method returns
a list of two targets: the PCH as the first element, and the object file as the second
element. Normally the object file is ignored. This builder method is only provided
when Microsoft Visual C++ is being used as the compiler. The PCH builder method is
generally used in conjunction with the PCH construction variable to force object files
to use the precompiled header:

env['PCH'] = env.PCH('StdAfx.cpp')[0]

PDF(), env.PDF()
Builds a .pdf file from a .dvi input file (or, by extension, a .tex, .ltx, or .latex
input file). The suffix specified by the $PDFSUFFIX construction variable (.pdf by
default) is added automatically to the target if it is not already present. Example:

# builds from aaa.tex
env.PDF(target = 'aaa.pdf', source = 'aaa.tex')
# builds bbb.pdf from bbb.dvi
env.PDF(target = 'bbb', source = 'bbb.dvi')

POInit(), env.POInit()
This builder belongs to msginit tool. The builder initializes missing PO file(s) if
$POAUTOINIT is set. If $POAUTOINIT is not set (default), POInit prints instruction for
user (that is supposed to be a translator), telling how the PO file should be
initialized. In normal projects you should not use POInit and use POUpdate instead.
POUpdate chooses intelligently between msgmerge(1) and msginit(1). POInit always uses
msginit(1) and should be regarded as builder for special purposes or for temporary use
(e.g. for quick, one time initialization of a bunch of PO files) or for tests.

Target nodes defined through POInit are not built by default (they're Ignored from '.'
node) but are added to special Alias ('po-create' by default). The alias name may be
changed through the $POCREATE_ALIAS construction variable. All PO files defined
through POInit may be easily initialized by scons po-create.

Example 1. Initialize en.po and pl.po from messages.pot:

# ...
env.POInit(['en', 'pl']) # messages.pot --> [en.po, pl.po]

Example 2. Initialize en.po and pl.po from foo.pot:

# ...
env.POInit(['en', 'pl'], ['foo']) # foo.pot --> [en.po, pl.po]

Example 3. Initialize en.po and pl.po from foo.pot but using $POTDOMAIN construction
variable:

# ...
env.POInit(['en', 'pl'], POTDOMAIN='foo') # foo.pot --> [en.po, pl.po]

Example 4. Initialize PO files for languages defined in LINGUAS file. The files will
be initialized from template messages.pot:

# ...
env.POInit(LINGUAS_FILE = 1) # needs 'LINGUAS' file

Example 5. Initialize en.po and pl.pl PO files plus files for languages defined in
LINGUAS file. The files will be initialized from template messages.pot:

# ...
env.POInit(['en', 'pl'], LINGUAS_FILE = 1)

Example 6. You may preconfigure your environment first, and then initialize PO files:

# ...
env['POAUTOINIT'] = 1
env['LINGUAS_FILE'] = 1
env['POTDOMAIN'] = 'foo'
env.POInit()

which has same efect as:

# ...
env.POInit(POAUTOINIT = 1, LINGUAS_FILE = 1, POTDOMAIN = 'foo')

PostScript(), env.PostScript()
Builds a .ps file from a .dvi input file (or, by extension, a .tex, .ltx, or .latex
input file). The suffix specified by the $PSSUFFIX construction variable (.ps by
default) is added automatically to the target if it is not already present. Example:

# builds from aaa.tex
env.PostScript(target = 'aaa.ps', source = 'aaa.tex')
# builds bbb.ps from bbb.dvi
env.PostScript(target = 'bbb', source = 'bbb.dvi')

POTUpdate(), env.POTUpdate()
The builder belongs to xgettext tool. The builder updates target POT file if exists or
creates one if it doesn't. The node is not built by default (i.e. it is Ignored from
'.'), but only on demand (i.e. when given POT file is required or when special alias
is invoked). This builder adds its targe node (messages.pot, say) to a special alias
(pot-update by default, see $POTUPDATE_ALIAS) so you can update/create them easily
with scons pot-update. The file is not written until there is no real change in
internationalized messages (or in comments that enter POT file).

Note
You may see xgettext(1) being invoked by the xgettext tool even if there is no
real change in internationalized messages (so the POT file is not being updated).
This happens every time a source file has changed. In such case we invoke
xgettext(1) and compare its output with the content of POT file to decide whether
the file should be updated or not.

Example 1. Let's create po/ directory and place following SConstruct script there:

# SConstruct in 'po/' subdir
env = Environment( tools = ['default', 'xgettext'] )
env.POTUpdate(['foo'], ['../a.cpp', '../b.cpp'])
env.POTUpdate(['bar'], ['../c.cpp', '../d.cpp'])

Then invoke scons few times:

user@host:$ scons # Does not create foo.pot nor bar.pot
user@host:$ scons foo.pot # Updates or creates foo.pot
user@host:$ scons pot-update # Updates or creates foo.pot and bar.pot
user@host:$ scons -c # Does not clean foo.pot nor bar.pot.

the results shall be as the comments above say.

Example 2. The POTUpdate builder may be used with no target specified, in which case
default target messages.pot will be used. The default target may also be overridden by
setting $POTDOMAIN construction variable or providing it as an override to POTUpdate
builder:

# SConstruct script
env = Environment( tools = ['default', 'xgettext'] )
env['POTDOMAIN'] = "foo"
env.POTUpdate(source = ["a.cpp", "b.cpp"]) # Creates foo.pot ...
env.POTUpdate(POTDOMAIN = "bar", source = ["c.cpp", "d.cpp"]) # and bar.pot

Example 3. The sources may be specified within separate file, for example
POTFILES.in:

# POTFILES.in in 'po/' subdirectory
../a.cpp
../b.cpp
# end of file

The name of the file (POTFILES.in) containing the list of sources is provided via
$XGETTEXTFROM:

# SConstruct file in 'po/' subdirectory
env = Environment( tools = ['default', 'xgettext'] )
env.POTUpdate(XGETTEXTFROM = 'POTFILES.in')

Example 4. You may use $XGETTEXTPATH to define source search path. Assume, for
example, that you have files a.cpp, b.cpp, po/SConstruct, po/POTFILES.in. Then your
POT-related files could look as below:

# POTFILES.in in 'po/' subdirectory
a.cpp
b.cpp
# end of file

# SConstruct file in 'po/' subdirectory
env = Environment( tools = ['default', 'xgettext'] )
env.POTUpdate(XGETTEXTFROM = 'POTFILES.in', XGETTEXTPATH='../')

Example 5. Multiple search directories may be defined within a list, i.e.
XGETTEXTPATH = ['dir1', 'dir2', ...]. The order in the list determines the search
order of source files. The path to the first file found is used.

Let's create 0/1/po/SConstruct script:

# SConstruct file in '0/1/po/' subdirectory
env = Environment( tools = ['default', 'xgettext'] )
env.POTUpdate(XGETTEXTFROM = 'POTFILES.in', XGETTEXTPATH=['../', '../../'])

and 0/1/po/POTFILES.in:

# POTFILES.in in '0/1/po/' subdirectory
a.cpp
# end of file

Write two *.cpp files, the first one is 0/a.cpp:

/* 0/a.cpp */
gettext("Hello from ../../a.cpp")

and the second is 0/1/a.cpp:

/* 0/1/a.cpp */
gettext("Hello from ../a.cpp")

then run scons. You'll obtain 0/1/po/messages.pot with the message "Hello from
../a.cpp". When you reverse order in $XGETTEXTFOM, i.e. when you write SConscript as

# SConstruct file in '0/1/po/' subdirectory
env = Environment( tools = ['default', 'xgettext'] )
env.POTUpdate(XGETTEXTFROM = 'POTFILES.in', XGETTEXTPATH=['../../', '../'])

then the messages.pot will contain msgid "Hello from ../../a.cpp" line and not msgid
"Hello from ../a.cpp".

POUpdate(), env.POUpdate()
The builder belongs to msgmerge tool. The builder updates PO files with msgmerge(1),
or initializes missing PO files as described in documentation of msginit tool and
POInit builder (see also $POAUTOINIT). Note, that POUpdate does not add its targets to
po-create alias as POInit does.

Target nodes defined through POUpdate are not built by default (they're Ignored from
'.' node). Instead, they are added automatically to special Alias ('po-update' by
default). The alias name may be changed through the $POUPDATE_ALIAS construction
variable. You can easily update PO files in your project by scons po-update.

Example 1. Update en.po and pl.po from messages.pot template (see also $POTDOMAIN),
assuming that the later one exists or there is rule to build it (see POTUpdate):

# ...
env.POUpdate(['en','pl']) # messages.pot --> [en.po, pl.po]

Example 2. Update en.po and pl.po from foo.pot template:

# ...
env.POUpdate(['en', 'pl'], ['foo']) # foo.pot --> [en.po, pl.pl]

Example 3. Update en.po and pl.po from foo.pot (another version):

# ...
env.POUpdate(['en', 'pl'], POTDOMAIN='foo') # foo.pot -- > [en.po, pl.pl]

Example 4. Update files for languages defined in LINGUAS file. The files are updated
from messages.pot template:

# ...
env.POUpdate(LINGUAS_FILE = 1) # needs 'LINGUAS' file

Example 5. Same as above, but update from foo.pot template:

# ...
env.POUpdate(LINGUAS_FILE = 1, source = ['foo'])

Example 6. Update en.po and pl.po plus files for languages defined in LINGUAS file.
The files are updated from messages.pot template:

# produce 'en.po', 'pl.po' + files defined in 'LINGUAS':
env.POUpdate(['en', 'pl' ], LINGUAS_FILE = 1)

Example 7. Use $POAUTOINIT to automatically initialize PO file if it doesn't exist:

# ...
env.POUpdate(LINGUAS_FILE = 1, POAUTOINIT = 1)

Example 8. Update PO files for languages defined in LINGUAS file. The files are
updated from foo.pot template. All necessary settings are pre-configured via
environment.

# ...
env['POAUTOINIT'] = 1
env['LINGUAS_FILE'] = 1
env['POTDOMAIN'] = 'foo'
env.POUpdate()

Program(), env.Program()
Builds an executable given one or more object files or C, C++, D, or Fortran source
files. If any C, C++, D or Fortran source files are specified, then they will be
automatically compiled to object files using the Object builder method; see that
builder method's description for a list of legal source file suffixes and how they are
interpreted. The target executable file prefix, specified by the $PROGPREFIX
construction variable (nothing by default), and suffix, specified by the $PROGSUFFIX
construction variable (by default, .exe on Windows systems, nothing on POSIX systems),
are automatically added to the target if not already present. Example:

env.Program(target='foo', source=['foo.o', 'bar.c', 'baz.f'])

ProgramAllAtOnce(), env.ProgramAllAtOnce()
Builds an executable from D sources without first creating individual objects for each
file.

D sources can be compiled file-by-file as C and C++ source are, and D is integrated
into the scons Object and Program builders for this model of build. D codes can though
do whole source meta-programming (some of the testing frameworks do this). For this it
is imperative that all sources are compiled and linked in a single call to the D
compiler. This builder serves that purpose.

env.ProgramAllAtOnce('executable', ['mod_a.d, mod_b.d', 'mod_c.d'])

This command will compile the modules mod_a, mod_b, and mod_c in a single compilation
process without first creating object files for the modules. Some of the D compilers
will create executable.o others will not.

RES(), env.RES()
Builds a Microsoft Visual C++ resource file. This builder method is only provided when
Microsoft Visual C++ or MinGW is being used as the compiler. The .res (or .o for
MinGW) suffix is added to the target name if no other suffix is given. The source file
is scanned for implicit dependencies as though it were a C file. Example:

env.RES('resource.rc')

RMIC(), env.RMIC()
Builds stub and skeleton class files for remote objects from Java .class files. The
target is a directory relative to which the stub and skeleton class files will be
written. The source can be the names of .class files, or the objects return from the
Java builder method.

If the construction variable $JAVACLASSDIR is set, either in the environment or in the
call to the RMIC builder method itself, then the value of the variable will be
stripped from the beginning of any .class file names.

classes = env.Java(target = 'classdir', source = 'src')
env.RMIC(target = 'outdir1', source = classes)

env.RMIC(target = 'outdir2',
source = ['package/foo.class', 'package/bar.class'])

env.RMIC(target = 'outdir3',
source = ['classes/foo.class', 'classes/bar.class'],
JAVACLASSDIR = 'classes')

RPCGenClient(), env.RPCGenClient()
Generates an RPC client stub (_clnt.c) file from a specified RPC (.x) source file.
Because rpcgen only builds output files in the local directory, the command will be
executed in the source file's directory by default.

# Builds src/rpcif_clnt.c
env.RPCGenClient('src/rpcif.x')

RPCGenHeader(), env.RPCGenHeader()
Generates an RPC header (.h) file from a specified RPC (.x) source file. Because
rpcgen only builds output files in the local directory, the command will be executed
in the source file's directory by default.

# Builds src/rpcif.h
env.RPCGenHeader('src/rpcif.x')

RPCGenService(), env.RPCGenService()
Generates an RPC server-skeleton (_svc.c) file from a specified RPC (.x) source file.
Because rpcgen only builds output files in the local directory, the command will be
executed in the source file's directory by default.

# Builds src/rpcif_svc.c
env.RPCGenClient('src/rpcif.x')

RPCGenXDR(), env.RPCGenXDR()
Generates an RPC XDR routine (_xdr.c) file from a specified RPC (.x) source file.
Because rpcgen only builds output files in the local directory, the command will be
executed in the source file's directory by default.

# Builds src/rpcif_xdr.c
env.RPCGenClient('src/rpcif.x')

SharedLibrary(), env.SharedLibrary()
Builds a shared library (.so on a POSIX system, .dll on Windows) given one or more
object files or C, C++, D or Fortran source files. If any source files are given, then
they will be automatically compiled to object files. The target library file prefix,
specified by the $SHLIBPREFIX construction variable (by default, lib on POSIX systems,
nothing on Windows systems), and suffix, specified by the $SHLIBSUFFIX construction
variable (by default, .dll on Windows systems, .so on POSIX systems), are
automatically added to the target if not already present. Example:

env.SharedLibrary(target='bar', source=['bar.c', 'foo.o'])

On Windows systems, the SharedLibrary builder method will always build an import
library (.lib) in addition to the shared library (.dll), adding a .lib library with
the same basename if there is not already a .lib file explicitly listed in the
targets.

On Cygwin systems, the SharedLibrary builder method will always build an import
library (.dll.a) in addition to the shared library (.dll), adding a .dll.a library
with the same basename if there is not already a .dll.a file explicitly listed in the
targets.

Any object files listed in the source must have been built for a shared library (that
is, using the SharedObject builder method). scons will raise an error if there is any
mismatch.

On some platforms, there is a distinction between a shared library (loaded
automatically by the system to resolve external references) and a loadable module
(explicitly loaded by user action). For maximum portability, use the LoadableModule
builder for the latter.

When the $SHLIBVERSION construction variable is defined, a versioned shared library is
created. This modifies $SHLINKFLAGS as required, adds the version number to the
library name, and creates any symbolic links that are needed.

env.SharedLibrary(target='bar', source=['bar.c', 'foo.o'], SHLIBVERSION='1.5.2')

On a POSIX system, versions with a single token create exactly one symlink:
libbar.so.6 would have symlink libbar.so only. On a POSIX system, versions with two or
more tokens create exactly two symlinks: libbar.so.2.3.1 would have symlinks libbar.so
and libbar.so.2; on a Darwin (OSX) system the library would be libbar.2.3.1.dylib and
the link would be libbar.dylib.

On Windows systems, specifying register=1 will cause the .dll to be registered after
it is built. The command that is run is determined by the $REGSVR construction
variable (regsvr32 by default), and the flags passed are determined by $REGSVRFLAGS.
By default, $REGSVRFLAGS includes the /s option, to prevent dialogs from popping up
and requiring user attention when it is run. If you change $REGSVRFLAGS, be sure to
include the /s option. For example,

env.SharedLibrary(target='bar', source=['bar.cxx', 'foo.obj'], register=1)

will register bar.dll as a COM object when it is done linking it.

SharedObject(), env.SharedObject()
Builds an object file intended for inclusion in a shared library. Source files must
have one of the same set of extensions specified above for the StaticObject builder
method. On some platforms building a shared object requires additional compiler option
(e.g. -fPIC for gcc) in addition to those needed to build a normal (static) object,
but on some platforms there is no difference between a shared object and a normal
(static) one. When there is a difference, SCons will only allow shared objects to be
linked into a shared library, and will use a different suffix for shared objects. On
platforms where there is no difference, SCons will allow both normal (static) and
shared objects to be linked into a shared library, and will use the same suffix for
shared and normal (static) objects. The target object file prefix, specified by the
$SHOBJPREFIX construction variable (by default, the same as $OBJPREFIX), and suffix,
specified by the $SHOBJSUFFIX construction variable, are automatically added to the
target if not already present. Examples:

env.SharedObject(target='ddd', source='ddd.c')
env.SharedObject(target='eee.o', source='eee.cpp')
env.SharedObject(target='fff.obj', source='fff.for')

Note that the source files will be scanned according to the suffix mappings in the
SourceFileScanner object. See the section "Scanner Objects," below, for more
information.

StaticLibrary(), env.StaticLibrary()
Builds a static library given one or more object files or C, C++, D or Fortran source
files. If any source files are given, then they will be automatically compiled to
object files. The static library file prefix, specified by the $LIBPREFIX construction
variable (by default, lib on POSIX systems, nothing on Windows systems), and suffix,
specified by the $LIBSUFFIX construction variable (by default, .lib on Windows
systems, .a on POSIX systems), are automatically added to the target if not already
present. Example:

env.StaticLibrary(target='bar', source=['bar.c', 'foo.o'])

Any object files listed in the source must have been built for a static library (that
is, using the StaticObject builder method). scons will raise an error if there is any
mismatch.

StaticObject(), env.StaticObject()
Builds a static object file from one or more C, C++, D, or Fortran source files.
Source files must have one of the following extensions:

.asm assembly language file
.ASM assembly language file
.c C file
.C Windows: C file
POSIX: C++ file
.cc C++ file
.cpp C++ file
.cxx C++ file
.cxx C++ file
.c++ C++ file
.C++ C++ file
.d D file
.f Fortran file
.F Windows: Fortran file
POSIX: Fortran file + C pre-processor
.for Fortran file
.FOR Fortran file
.fpp Fortran file + C pre-processor
.FPP Fortran file + C pre-processor
.m Object C file
.mm Object C++ file
.s assembly language file
.S Windows: assembly language file
ARM: CodeSourcery Sourcery Lite
.sx assembly language file + C pre-processor
POSIX: assembly language file + C pre-processor
.spp assembly language file + C pre-processor
.SPP assembly language file + C pre-processor

The target object file prefix, specified by the $OBJPREFIX construction variable
(nothing by default), and suffix, specified by the $OBJSUFFIX construction variable
(.obj on Windows systems, .o on POSIX systems), are automatically added to the target
if not already present. Examples:

env.StaticObject(target='aaa', source='aaa.c')
env.StaticObject(target='bbb.o', source='bbb.c++')
env.StaticObject(target='ccc.obj', source='ccc.f')

Note that the source files will be scanned according to the suffix mappings in the
SourceFileScanner object. See the section "Scanner Objects," below, for more
information.

Substfile(), env.Substfile()
The Substfile builder creates a single text file from a template consisting of a file
or set of files (or nodes), replacing text using the $SUBST_DICT construction variable
(if set). If a set, they are concatenated into the target file using the value of the
$LINESEPARATOR construction variable as a separator between contents; the separator is
not emitted after the contents of the last file. Nested lists of source files are
flattened. See also Textfile.

If a single source file name is specified and has a .in suffix, the suffix is stripped
and the remainder of the name is used as the default target name.

The prefix and suffix specified by the $SUBSTFILEPREFIX and $SUBSTFILESUFFIX
construction variables (an empty string by default in both cases) are automatically
added to the target if they are not already present.

If a construction variable named $SUBST_DICT is present, it may be either a Python
dictionary or a sequence of (key, value) tuples. If it is a dictionary it is converted
into a list of tuples with unspecified order, so if one key is a prefix of another key
or if one substitution could be further expanded by another subsitition, it is
unpredictable whether the expansion will occur.

Any occurrences of a key in the source are replaced by the corresponding value, which
may be a Python callable function or a string. If the value is a callable, it is
called with no arguments to get a string. Strings are subst-expanded and the result
replaces the key.

env = Environment(tools=['default'])

env['prefix'] = '/usr/bin'
script_dict = {'@prefix@': '/bin', '@exec_prefix@': '$prefix'}
env.Substfile('script.in', SUBST_DICT=script_dict)

conf_dict = {'%VERSION%': '1.2.3', '%BASE%': 'MyProg'}
env.Substfile('config.h.in', conf_dict, SUBST_DICT=conf_dict)

# UNPREDICTABLE - one key is a prefix of another
bad_foo = {'$foo': '$foo', '$foobar': '$foobar'}
env.Substfile('foo.in', SUBST_DICT=bad_foo)

# PREDICTABLE - keys are applied longest first
good_foo = [('$foobar', '$foobar'), ('$foo', '$foo')]
env.Substfile('foo.in', SUBST_DICT=good_foo)

# UNPREDICTABLE - one substitution could be futher expanded
bad_bar = {'@bar@': '@soap@', '@soap@': 'lye'}
env.Substfile('bar.in', SUBST_DICT=bad_bar)

# PREDICTABLE - substitutions are expanded in order
good_bar = (('@bar@', '@soap@'), ('@soap@', 'lye'))
env.Substfile('bar.in', SUBST_DICT=good_bar)

# the SUBST_DICT may be in common (and not an override)
substutions = {}
subst = Environment(tools=['textfile'], SUBST_DICT=substitutions)
substitutions['@foo@'] = 'foo'
subst['SUBST_DICT']['@bar@'] = 'bar'
subst.Substfile(
'pgm1.c',
[Value('#include "@foo@.h"'), Value('#include "@bar@.h"'), "common.in", "pgm1.in"],
)
subst.Substfile(
'pgm2.c',
[Value('#include "@foo@.h"'), Value('#include "@bar@.h"'), "common.in", "pgm2.in"],
)

Tar(), env.Tar()
Builds a tar archive of the specified files and/or directories. Unlike most builder
methods, the Tar builder method may be called multiple times for a given target; each
additional call adds to the list of entries that will be built into the archive. Any
source directories will be scanned for changes to any on-disk files, regardless of
whether or not scons knows about them from other Builder or function calls.

env.Tar('src.tar', 'src')

# Create the stuff.tar file.
env.Tar('stuff', ['subdir1', 'subdir2'])
# Also add "another" to the stuff.tar file.
env.Tar('stuff', 'another')

# Set TARFLAGS to create a gzip-filtered archive.
env = Environment(TARFLAGS = '-c -z')
env.Tar('foo.tar.gz', 'foo')

# Also set the suffix to .tgz.
env = Environment(TARFLAGS = '-c -z',
TARSUFFIX = '.tgz')
env.Tar('foo')

Textfile(), env.Textfile()
The Textfile builder generates a single text file from a template consisting of a list
of strings, replacing text using the $SUBST_DICT construction variable (if set) - see
Substfile for a description of replacement. The strings will be separated in the
target file using the value of the $LINESEPARATOR construction variable; the line
separator is not emitted after the last string. Nested lists of source strings are
flattened. Source strings need not literally be Python strings: they can be Nodes or
Python objects that convert cleanly to Value nodes

The prefix and suffix specified by the $TEXTFILEPREFIX and $TEXTFILESUFFIX
construction variables (by default an empty string and .txt, respectively) are
automatically added to the target if they are not already present. Examples:

# builds/writes foo.txt
env.Textfile(target='foo.txt', source=['Goethe', 42, 'Schiller'])

# builds/writes bar.txt
env.Textfile(target='bar', source=['lalala', 'tanteratei'], LINESEPARATOR='|*')

# nested lists are flattened automatically
env.Textfile(target='blob', source=['lalala', ['Goethe', 42, 'Schiller'], 'tanteratei'])

# files may be used as input by wraping them in File()
env.Textfile(
target='concat', # concatenate files with a marker between
source=[File('concat1'), File('concat2')],
LINESEPARATOR='====================\n',
)

Results:

foo.txt

Goethe
42
Schiller

bar.txt

lalala|*tanteratei

blob.txt

lalala
Goethe
42
Schiller
tanteratei

Translate(), env.Translate()
This pseudo-builder belongs to gettext toolset. The builder extracts internationalized
messages from source files, updates POT template (if necessary) and then updates PO
translations (if necessary). If $POAUTOINIT is set, missing PO files will be
automatically created (i.e. without translator person intervention). The variables
$LINGUAS_FILE and $POTDOMAIN are taken into acount too. All other construction
variables used by POTUpdate, and POUpdate work here too.

Example 1. The simplest way is to specify input files and output languages inline in a
SCons script when invoking Translate

# SConscript in 'po/' directory
env = Environment( tools = ["default", "gettext"] )
env['POAUTOINIT'] = 1
env.Translate(['en','pl'], ['../a.cpp','../b.cpp'])

Example 2. If you wish, you may also stick to conventional style known from autotools,
i.e. using POTFILES.in and LINGUAS files

# LINGUAS
en pl
#end

# POTFILES.in
a.cpp
b.cpp
# end

# SConscript
env = Environment( tools = ["default", "gettext"] )
env['POAUTOINIT'] = 1
env['XGETTEXTPATH'] = ['../']
env.Translate(LINGUAS_FILE = 1, XGETTEXTFROM = 'POTFILES.in')

The last approach is perhaps the recommended one. It allows easily split
internationalization/localization onto separate SCons scripts, where a script in
source tree is responsible for translations (from sources to PO files) and script(s)
under variant directories are responsible for compilation of PO to MO files to and for
installation of MO files. The "gluing factor" synchronizing these two scripts is then
the content of LINGUAS file. Note, that the updated POT and PO files are usually going
to be committed back to the repository, so they must be updated within the source
directory (and not in variant directories). Additionaly, the file listing of po/
directory contains LINGUAS file, so the source tree looks familiar to translators, and
they may work with the project in their usual way.

Example 3. Let's prepare a development tree as below

project/
+ SConstruct
+ build/
+ src/
+ po/
+ SConscript
+ SConscript.i18n
+ POTFILES.in
+ LINGUAS

with build being variant directory. Write the top-level SConstruct script as follows

# SConstruct
env = Environment( tools = ["default", "gettext"] )
VariantDir('build', 'src', duplicate = 0)
env['POAUTOINIT'] = 1
SConscript('src/po/SConscript.i18n', exports = 'env')
SConscript('build/po/SConscript', exports = 'env')

the src/po/SConscript.i18n as

# src/po/SConscript.i18n
Import('env')
env.Translate(LINGUAS_FILE=1, XGETTEXTFROM='POTFILES.in', XGETTEXTPATH=['../'])

and the src/po/SConscript

# src/po/SConscript
Import('env')
env.MOFiles(LINGUAS_FILE = 1)

Such setup produces POT and PO files under source tree in src/po/ and binary MO files
under variant tree in build/po/. This way the POT and PO files are separated from
other output files, which must not be committed back to source repositories (e.g. MO
files).

Note
In above example, the PO files are not updated, nor created automatically when you
issue scons '.' command. The files must be updated (created) by hand via scons
po-update and then MO files can be compiled by running scons '.'.

TypeLibrary(), env.TypeLibrary()
Builds a Windows type library (.tlb) file from an input IDL file (.idl). In addition,
it will build the associated interface stub and proxy source files, naming them
according to the base name of the .idl file. For example,

env.TypeLibrary(source="foo.idl")

Will create foo.tlb, foo.h, foo_i.c, foo_p.c and foo_data.c files.

Uic(), env.Uic()
Builds a header file, an implementation file and a moc file from an ui file. and
returns the corresponding nodes in the above order. This builder is only available
after using the tool 'qt'. Note: you can specify .ui files directly as source files to
the Program, Library and SharedLibrary builders without using this builder. Using this
builder lets you override the standard naming conventions (be careful: prefixes are
always prepended to names of built files; if you don't want prefixes, you may set them
to ``). See the $QTDIR variable for more information. Example:

env.Uic('foo.ui') # -> ['foo.h', 'uic_foo.cc', 'moc_foo.cc']
env.Uic(target = Split('include/foo.h gen/uicfoo.cc gen/mocfoo.cc'),
source = 'foo.ui') # -> ['include/foo.h', 'gen/uicfoo.cc', 'gen/mocfoo.cc']

Zip(), env.Zip()
Builds a zip archive of the specified files and/or directories. Unlike most builder
methods, the Zip builder method may be called multiple times for a given target; each
additional call adds to the list of entries that will be built into the archive. Any
source directories will be scanned for changes to any on-disk files, regardless of
whether or not scons knows about them from other Builder or function calls.

env.Zip('src.zip', 'src')

# Create the stuff.zip file.
env.Zip('stuff', ['subdir1', 'subdir2'])
# Also add "another" to the stuff.tar file.
env.Zip('stuff', 'another')

All targets of builder methods automatically depend on their sources. An explicit
dependency can be specified using the env.Depends method of a construction environment
(see below).

In addition, scons automatically scans source files for various programming languages, so
the dependencies do not need to be specified explicitly. By default, SCons can C source
files, C++ source files, Fortran source files with .F (POSIX systems only), .fpp, or .FPP
file extensions, and assembly language files with .S (POSIX systems only), .spp, or .SPP
files extensions for C preprocessor dependencies. SCons also has default support for
scanning D source files, You can also write your own Scanners to add support for
additional source file types. These can be added to the default Scanner object used by the
Object, StaticObject and SharedObject Builders by adding them to the SourceFileScanner
object. See the section called “Scanner Objects” for more information about defining your
own Scanner objects and using the SourceFileScanner object.

Methods and Functions To Do Things
In addition to Builder methods, scons provides a number of other construction environment
methods and global functions to manipulate the build configuration.

Usually, a construction environment method and global function with the same name both
exist for convenience. In the following list, the global function is documented in this
style:

Function(arguments, [optional arguments])

and the construction environment method looks like:

env.Function(arguments, [optional arguments])

If the function can be called both ways, then both forms are listed.

The global function and same-named construction environment method provide almost
identical functionality, with a couple of exceptions. First, many of the construction
environment methods affect only that construction environment, while the global function
has a global effect. Second, where appropriate, calling the functionality through a
construction environment will substitute construction variables into any supplied string
arguments, while the global function doesn't have the context of a construction
environment to pick variables from, so it cannot perform the substitution. For example:

Default('$FOO')

env = Environment(FOO='foo')
env.Default('$FOO')

In the above example, the call to the global Default function will add a target named $FOO
to the list of default targets, while the call to the env.Default construction environment
method will expand the value and add a target named foo to the list of default targets.
For more on construction variable expansion, see the next section on construction
variables.

Global functions may be called from custom Python modules that you import into an
SConscript file by adding the following import to the Python module:

from SCons.Script import *

Construction environment methods and global functions provided by scons include:

Action(action, [cmd/str/fun, [var, ...]] [option=value, ...]), env.Action(action,
[cmd/str/fun, [var, ...]] [option=value, ...])
A factory function to create an Action object for the specified action. See the
manpage section "Action Objects" for a complete explanation of the arguments and
behavior.

Note that the env.Action form of the invocation will expand construction variables in
any argument strings, including the action argument, at the time it is called using
the construction variables in the env construction environment through which
env.Action was called. The Action global function form delays all variable expansion
until the Action object is actually used.

AddMethod(object, function, [name]), env.AddMethod(function, [name])
When called with the AddMethod() form, adds the specified function to the specified
object as the specified method name. When called using the env.AddMethod form, adds
the specified function to the construction environment env as the specified method
name. In both cases, if name is omitted or None, the name of the specified function
itself is used for the method name.

Examples:

# Note that the first argument to the function to
# be attached as a method must be the object through
# which the method will be called; the Python
# convention is to call it 'self'.
def my_method(self, arg):
print("my_method() got", arg)

# Use the global AddMethod() function to add a method
# to the Environment class. This
AddMethod(Environment, my_method)
env = Environment()
env.my_method('arg')

# Add the function as a method, using the function
# name for the method call.
env = Environment()
env.AddMethod(my_method, 'other_method_name')
env.other_method_name('another arg')

AddOption(arguments)
Adds a local (project-specific) command-line option. arguments are the same as those
supported by the add_option method in the standard Python library module optparse,
with a few additional capabilities noted below. See the documentation for optparse for
a thorough discussion of its option-processing capabities.

In addition to the arguments and values supported by the optparse add_option method,
AddOption allows setting the nargs keyword value to a string consisting of a question
mark ('?') to indicate that the option argument for that option string is optional. If
the option string is present on the command line but has no matching option argument,
the value of the const keyword argument is produced as the value of the option. If the
option string is omitted from the command line, the value of the default keyword
argument is produced, as usual; if there is no default keyword argument in the
AddOption call, None is produced.

optparse recognizes abbreviations of long option names, as long as they can be
unambiguously resolved. For example, if add_option is called to define a --devicename
option, it will recognize --device, --dev and so forth as long as there is no other
option which could also match to the same abbreviation. Options added via AddOption do
not support the automatic recognition of abbreviations. Instead, to allow specific
abbreviations, include them in the AddOption call.

Once a new command-line option has been added with AddOption, the option value may be
accessed using GetOption or env.GetOption. SetOption is not currently supported for
options added with AddOption.

Help text for an option is a combination of the string supplied in the help keyword
argument to AddOption and information collected from the other keyword arguments. Such
help is displayed if the -h command line option is used (but not with -H). Help for
all local options is displayed under the separate heading Local Options. The options
are unsorted - they will appear in the help text in the order in which the AddOption
calls occur.

Example:

AddOption(
'--prefix',
dest='prefix',
nargs=1,
type='string',
action='store',
metavar='DIR',
help='installation prefix',
)
env = Environment(PREFIX=GetOption('prefix'))

For that example, the following help text would be produced:

Local Options:
--prefix=DIR installation prefix

Help text for local options may be unavailable if the Help function has been called,
see the Help documentation for details.

Note
As an artifact of the internal implementation, the behavior of options added by
AddOption which take option arguments is undefined if whitespace (rather than an =
sign) is used as the separator on the command line. Users should avoid such usage;
it is recommended to add a note to this effect to project documentation if the
situation is likely to arise. In addition, if the nargs keyword is used to specify
more than one following option argument (that is, with a value of 2 or greater),
such arguments would necessarily be whitespace separated, triggering the issue.
Developers should not use AddOption this way. Future versions of SCons will likely
forbid such usage.

AddPostAction(target, action), env.AddPostAction(target, action)
Arranges for the specified action to be performed after the specified target has been
built. The specified action(s) may be an Action object, or anything that can be
converted into an Action object See the manpage section "Action Objects" for a
complete explanation.

When multiple targets are supplied, the action may be called multiple times, once
after each action that generates one or more targets in the list.

AddPreAction(target, action), env.AddPreAction(target, action)
Arranges for the specified action to be performed before the specified target is
built. The specified action(s) may be an Action object, or anything that can be
converted into an Action object See the manpage section "Action Objects" for a
complete explanation.

When multiple targets are specified, the action(s) may be called multiple times, once
before each action that generates one or more targets in the list.

Note that if any of the targets are built in multiple steps, the action will be
invoked just before the "final" action that specifically generates the specified
target(s). For example, when building an executable program from a specified source .c
file via an intermediate object file:

foo = Program('foo.c')
AddPreAction(foo, 'pre_action')

The specified pre_action would be executed before scons calls the link command that
actually generates the executable program binary foo, not before compiling the foo.c
file into an object file.

Alias(alias, [targets, [action]]), env.Alias(alias, [targets, [action]])
Creates one or more phony targets that expand to one or more other targets. An
optional action (command) or list of actions can be specified that will be executed
whenever the any of the alias targets are out-of-date. Returns the Node object
representing the alias, which exists outside of any file system. This Node object, or
the alias name, may be used as a dependency of any other target, including another
alias. Alias can be called multiple times for the same alias to add additional
targets to the alias, or additional actions to the list for this alias. Aliases are
global even if set through the construction environment method.

Examples:

Alias('install')
Alias('install', '/usr/bin')
Alias(['install', 'install-lib'], '/usr/local/lib')

env.Alias('install', ['/usr/local/bin', '/usr/local/lib'])
env.Alias('install', ['/usr/local/man'])

env.Alias('update', ['file1', 'file2'], "update_database $SOURCES")

AllowSubstExceptions([exception, ...])
Specifies the exceptions that will be allowed when expanding construction variables.
By default, any construction variable expansions that generate a NameError or
IndexError exception will expand to a '' (an empty string) and not cause scons to
fail. All exceptions not in the specified list will generate an error message and
terminate processing.

If AllowSubstExceptions is called multiple times, each call completely overwrites the
previous list of allowed exceptions.

Example:

# Requires that all construction variable names exist.
# (You may wish to do this if you want to enforce strictly
# that all construction variables must be defined before use.)
AllowSubstExceptions()

# Also allow a string containing a zero-division expansion
# like '${1 / 0}' to evalute to ''.
AllowSubstExceptions(IndexError, NameError, ZeroDivisionError)

AlwaysBuild(target, ...), env.AlwaysBuild(target, ...)
Marks each given target so that it is always assumed to be out of date, and will
always be rebuilt if needed. Note, however, that AlwaysBuild does not add its
target(s) to the default target list, so the targets will only be built if they are
specified on the command line, or are a dependent of a target specified on the command
line--but they will always be built if so specified. Multiple targets can be passed in
to a single call to AlwaysBuild.

env.Append(key=val, [...])
Appends the specified keyword arguments to the end of construction variables in the
environment. If the Environment does not have the specified construction variable, it
is simply added to the environment. If the values of the construction variable and the
keyword argument are the same type, then the two values will be simply added together.
Otherwise, the construction variable and the value of the keyword argument are both
coerced to lists, and the lists are added together. (See also the Prepend method).

Example:

env.Append(CCFLAGS = ' -g', FOO = ['foo.yyy'])

env.AppendENVPath(name, newpath, [envname, sep, delete_existing])
This appends new path elements to the given path in the specified external environment
(ENV by default). This will only add any particular path once (leaving the last one it
encounters and ignoring the rest, to preserve path order), and to help assure this,
will normalize all paths (using os.path.normpath and os.path.normcase). This can also
handle the case where the given old path variable is a list instead of a string, in
which case a list will be returned instead of a string.

If delete_existing is 0, then adding a path that already exists will not move it to
the end; it will stay where it is in the list.

Example:

print 'before:',env['ENV']['INCLUDE']
include_path = '/foo/bar:/foo'
env.AppendENVPath('INCLUDE', include_path)
print 'after:',env['ENV']['INCLUDE']

yields:
before: /foo:/biz
after: /biz:/foo/bar:/foo

env.AppendUnique(key=val, [...], delete_existing=0)
Appends the specified keyword arguments to the end of construction variables in the
environment. If the Environment does not have the specified construction variable, it
is simply added to the environment. If the construction variable being appended to is
a list, then any value(s) that already exist in the construction variable will not be
added again to the list. However, if delete_existing is 1, existing matching values
are removed first, so existing values in the arg list move to the end of the list.

Example:

env.AppendUnique(CCFLAGS = '-g', FOO = ['foo.yyy'])

Builder(action, [arguments]), env.Builder(action, [arguments])
Creates a Builder object for the specified action. See the manpage section "Builder
Objects" for a complete explanation of the arguments and behavior.

Note that the env.Builder() form of the invocation will expand construction variables
in any arguments strings, including the action argument, at the time it is called
using the construction variables in the env construction environment through which
env.Builder was called. The Builder form delays all variable expansion until after the
Builder object is actually called.

CacheDir(cache_dir), env.CacheDir(cache_dir)
Direct scons to maintain a derived-file cache in cache_dir. The derived files in the
cache will be shared among all the builds specifying the same cache_dir. Specifying a
cache_dir of None disables derived file caching.

Calling the environment method env.CacheDir limits the effect to targets built through
the specified construction environment. Calling the global function CacheDir sets a
global default that will be used by all targets built through construction
environments that do not set up environment-specific caching by calling env.CacheDir.

When derived-file caching is being used and scons finds a derived file that needs to
be rebuilt, it will first look in the cache to see if a file with matching build
signature exists (indicating the input file(s) and build action(s) were identical to
those for the current target), and if so, will retrieve the file from the cache.
scons will report Retrieved `file' from cache instead of the normal build message. If
the derived file is not present in the cache, scons will build it and then place a
copy of the built file in the cache, identified by its build signature, for future
use.

The Retrieved `file' from cache messages are useful for human consumption, but less so
when comparing log files between scons runs which will show differences that are noisy
and not actually significant. To disable, use the --cache-show option. With this
option, scons will print the action that would have been used to build the file
without considering cache retrieval.

Derived-file caching may be disabled for any invocation of scons by giving the
--cache-disable command line option. Cache updating may be disabled, leaving cache
fetching enabled, by giving the --cache-readonly.

If the --cache-force option is used, scons will place a copy of all derived files in
the cache, even if they already existed and were not built by this invocation. This is
useful to populate a cache the first time a cache_dir is used for a build, or to bring
a cache up to date after a build with cache updating disabled (--cache-disable or
--cache-readonly) has been done.

The NoCache method can be used to disable caching of specific files. This can be
useful if inputs and/or outputs of some tool are impossible to predict or
prohibitively large.

Clean(targets, files_or_dirs), env.Clean(targets, files_or_dirs)
This specifies a list of files or directories which should be removed whenever the
targets are specified with the -c command line option. The specified targets may be a
list or an individual target. Multiple calls to Clean are legal, and create new
targets or add files and directories to the clean list for the specified targets.

Multiple files or directories should be specified either as separate arguments to the
Clean method, or as a list. Clean will also accept the return value of any of the
construction environment Builder methods. Examples:

The related NoClean function overrides calling Clean for the same target, and any
targets passed to both functions will not be removed by the -c option.

Examples:

Clean('foo', ['bar', 'baz'])
Clean('dist', env.Program('hello', 'hello.c'))
Clean(['foo', 'bar'], 'something_else_to_clean')

In this example, installing the project creates a subdirectory for the documentation.
This statement causes the subdirectory to be removed if the project is deinstalled.

Clean(docdir, os.path.join(docdir, projectname))

env.Clone([key=val, ...])
Returns a separate copy of a construction environment. If there are any keyword
arguments specified, they are added to the returned copy, overwriting any existing
values for the keywords.

Example:

env2 = env.Clone()
env3 = env.Clone(CCFLAGS = '-g')

Additionally, a list of tools and a toolpath may be specified, as in the Environment
constructor:

def MyTool(env): env['FOO'] = 'bar'
env4 = env.Clone(tools = ['msvc', MyTool])

The parse_flags keyword argument is also recognized to allow merging command-line
style arguments into the appropriate construction variables (see env.MergeFlags).

# create an environment for compiling programs that use wxWidgets
wx_env = env.Clone(parse_flags='!wx-config --cflags --cxxflags')

Command(target, source, action, [key=val, ...]), env.Command(target, source, action,
[key=val, ...])
Executes a specific action (or list of actions) to build a target file or files from a
source file or files. This is more convenient than defining a separate Builder object
for a single special-case build.

The Command function accepts source_scanner, target_scanner, source_factory, and
target_factory keyword arguments. These arguments can be used to specify a Scanner
object that will be used to apply a custom scanner for a source or target. For
example, the global DirScanner object can be used if any of the sources will be
directories that must be scanned on-disk for changes to files that aren't already
specified in other Builder of function calls. The *_factory arguments take a factory
function that Command will use to turn any sources or targets specified as strings
into SCons Nodes. See the manpage section "Builder Objects" for more information about
how these arguments work in a Builder.

Any other keyword arguments specified override any same-named existing construction
variables.

An action can be an external command, specified as a string, or a callable Python
object; see the manpage section "Action Objects" for more complete information. Also
note that a string specifying an external command may be preceded by an at-sign (@) to
suppress printing the command in question, or by a hyphen (-) to ignore the exit
status of the external command.

Examples:

env.Command(
target='foo.out',
source='foo.in',
action="$FOO_BUILD < $SOURCES > $TARGET"
)

env.Command(
target='bar.out',
source='bar.in',
action=["rm -f $TARGET", "$BAR_BUILD < $SOURCES > $TARGET"],
ENV={'PATH': '/usr/local/bin/'},
)

import os
def rename(env, target, source):
os.rename('.tmp', str(target[0]))

env.Command(
target='baz.out',
source='baz.in',
action=["$BAZ_BUILD < $SOURCES > .tmp", rename],
)

Note that the Command function will usually assume, by default, that the specified
targets and/or sources are Files, if no other part of the configuration identifies
what type of entries they are. If necessary, you can explicitly specify that targets
or source nodes should be treated as directories by using the Dir or env.Dir
functions.

Examples:

env.Command('ddd.list', Dir('ddd'), 'ls -l $SOURCE > $TARGET')

env['DISTDIR'] = 'destination/directory'
env.Command(env.Dir('$DISTDIR')), None, make_distdir)

Also note that SCons will usually automatically create any directory necessary to hold
a target file, so you normally don't need to create directories by hand.

Configure(env, [custom_tests, conf_dir, log_file, config_h]), env.Configure([custom_tests,
conf_dir, log_file, config_h])
Creates a Configure object for integrated functionality similar to GNU autoconf. See
the manpage section "Configure Contexts" for a complete explanation of the arguments
and behavior.

Decider(function), env.Decider(function)
Specifies that all up-to-date decisions for targets built through this construction
environment will be handled by the specified function. function can be the name of a
function or one of the following strings that specify the predefined decision function
that will be applied:

"timestamp-newer"
Specifies that a target shall be considered out of date and rebuilt if the
dependency's timestamp is newer than the target file's timestamp. This is the
behavior of the classic Make utility, and make can be used a synonym for
timestamp-newer.

"timestamp-match"
Specifies that a target shall be considered out of date and rebuilt if the
dependency's timestamp is different than the timestamp recorded the last time the
target was built. This provides behavior very similar to the classic Make utility
(in particular, files are not opened up so that their contents can be checksummed)
except that the target will also be rebuilt if a dependency file has been restored
to a version with an earlier timestamp, such as can happen when restoring files
from backup archives.

"MD5"
Specifies that a target shall be considered out of date and rebuilt if the
dependency's content has changed since the last time the target was built, as
determined be performing an MD5 checksum on the dependency's contents and
comparing it to the checksum recorded the last time the target was built. content
can be used as a synonym for MD5.

"MD5-timestamp"
Specifies that a target shall be considered out of date and rebuilt if the
dependency's content has changed since the last time the target was built, except
that dependencies with a timestamp that matches the last time the target was
rebuilt will be assumed to be up-to-date and not rebuilt. This provides behavior
very similar to the MD5 behavior of always checksumming file contents, with an
optimization of not checking the contents of files whose timestamps haven't
changed. The drawback is that SCons will not detect if a file's content has
changed but its timestamp is the same, as might happen in an automated script that
runs a build, updates a file, and runs the build again, all within a single
second.

Examples:

# Use exact timestamp matches by default.
Decider('timestamp-match')

# Use MD5 content signatures for any targets built
# with the attached construction environment.
env.Decider('content')

In addition to the above already-available functions, the function argument may be a
Python function you supply. Such a function must accept the following four arguments:

dependency
The Node (file) which should cause the target to be rebuilt if it has "changed"
since the last tme target was built.

target
The Node (file) being built. In the normal case, this is what should get rebuilt
if the dependency has "changed."

prev_ni
Stored information about the state of the dependency the last time the target was
built. This can be consulted to match various file characteristics such as the
timestamp, size, or content signature.

repo_node
If set, use this Node instead of the one specified by dependency to determine if
the dependency has changed. This argument is optional so should be written as a
default argument (typically it would be written as repo_node=None). A caller will
normally only set this if the target only exists in a Repository.

The function should return a value which evaluates True if the dependency has
"changed" since the last time the target was built (indicating that the target should
be rebuilt), and a value which evaluates False otherwise (indicating that the target
should not be rebuilt). Note that the decision can be made using whatever criteria are
appopriate. Ignoring some or all of the function arguments is perfectly normal.

Example:

def my_decider(dependency, target, prev_ni, repo_node=None):
return not os.path.exists(str(target))

env.Decider(my_decider)

Default(targets...), env.Default(targets...)
This specifies a list of default targets, which will be built by scons if no explicit
targets are given on the command line. Multiple calls to Default are legal, and add to
the list of default targets. As noted above, both forms of this call affect the same
global list of default targets; the construction environment method applies
construction variable expansion to the targets.

Multiple targets should be specified as separate arguments to the Default method, or
as a list. Default will also accept the Node returned by any of a construction
environment's builder methods.

Examples:

Default('foo', 'bar', 'baz')
env.Default(['a', 'b', 'c'])
hello = env.Program('hello', 'hello.c')
env.Default(hello)

An argument to Default of None will clear all default targets. Later calls to Default
will add to the (now empty) default-target list like normal.

The current list of targets added using the Default function or method is available in
the DEFAULT_TARGETS list; see below.

DefaultEnvironment([**kwargs])
Instantiates and returns the default construction environment object. The default
environment is used internally by SCons in order to execute many of the global
functions in this list (that is, those not called as methods of a specific
construction environment). It is not mandatory to call DefaultEnvironment: the default
environment will be instantiated automatically when the build phase begins if the
function has not been called, however calling it explicitly gives the opportunity to
affect and examine the contents of the default environment.

The default environment is a singleton, so the keyword arguments affect it only on the
first call, on subsequent calls the already-constructed object is returned and any
keyword arguments are silently ignored. The default environment can be modified after
instantiation in the same way as any construction environment. Modifying the default
environment has no effect on the construction environment constructed by an
Environment or Clone call.

Depends(target, dependency), env.Depends(target, dependency)
Specifies an explicit dependency; the target will be rebuilt whenever the dependency
has changed. Both the specified target and dependency can be a string (usually the
path name of a file or directory) or Node objects, or a list of strings or Node
objects (such as returned by a Builder call). This should only be necessary for cases
where the dependency is not caught by a Scanner for the file.

Example:

env.Depends('foo', 'other-input-file-for-foo')

mylib = env.Library('mylib.c')
installed_lib = env.Install('lib', mylib)
bar = env.Program('bar.c')

# Arrange for the library to be copied into the installation
# directory before trying to build the "bar" program.
# (Note that this is for example only. A "real" library
# dependency would normally be configured through the $LIBS
# and $LIBPATH variables, not using an env.Depends() call.)

env.Depends(bar, installed_lib)

env.Detect(progs)
Find an executable from one or more choices: progs may be a string or a list of
strings. Returns the first value from progs that was found, or None. Executable is
searched by checking the paths specified by env['ENV']['PATH']. On Windows systems,
additionally applies the filename suffixes found in env['ENV']['PATHEXT'] but will not
include any such extension in the return value. env.Detect is a wrapper around
env.WhereIs.

env.Dictionary([vars])
Returns a dictionary object containing the construction variables in the construction
environment. If there are any arguments specified, the values of the specified
construction variables are returned as a string (if one argument) or as a list of
strings.

Example:

cvars = env.Dictionary()
cc_values = env.Dictionary('CC', 'CCFLAGS', 'CCCOM')

Dir(name, [directory]), env.Dir(name, [directory])
Returns Directory Node(s). A Directory Node is an object that represents a directory.
name can be a relative or absolute path or a list of such paths. directory is an
optional directory that will be used as the parent directory. If no directory is
specified, the current script's directory is used as the parent.

If name is a single pathname, the corresponding node is returned. If name is a list,
SCons returns a list of nodes. Construction variables are expanded in name.

Directory Nodes can be used anywhere you would supply a string as a directory name to
a Builder method or function. Directory Nodes have attributes and methods that are
useful in many situations; see manpage section "File and Directory Nodes" for more
information.

env.Dump([key], [format])
Serializes construction variables to a string. The method supports the following
formats specified by format:

pretty
Returns a pretty printed representation of the environment (if format is not
specified, this is the default).

json
Returns a JSON-formatted string representation of the environment.

If key is None (the default) the entire dictionary of construction variables is
serialized. If supplied, it is taken as the name of a construction variable whose
value is serialized.

This SConstruct:

env=Environment()
print(env.Dump('CCCOM'))

will print:

'$CC -c -o $TARGET $CCFLAGS $CPPFLAGS $_CPPDEFFLAGS $_CPPINCFLAGS $SOURCES'

While this SConstruct:

env=Environment()
print(env.Dump())

will print:

{ 'AR': 'ar',
'ARCOM': '$AR $ARFLAGS $TARGET $SOURCES\n$RANLIB $RANLIBFLAGS $TARGET',
'ARFLAGS': ['r'],
'AS': 'as',
'ASCOM': '$AS $ASFLAGS -o $TARGET $SOURCES',
'ASFLAGS': [],
...

EnsurePythonVersion(major, minor), env.EnsurePythonVersion(major, minor)
Ensure that the Python version is at least major.minor. This function will print out
an error message and exit SCons with a non-zero exit code if the actual Python version
is not late enough.

Example:

EnsurePythonVersion(2,2)

EnsureSConsVersion(major, minor, [revision]), env.EnsureSConsVersion(major, minor,
[revision])
Ensure that the SCons version is at least major.minor, or major.minor.revision. if
revision is specified. This function will print out an error message and exit SCons
with a non-zero exit code if the actual SCons version is not late enough.

Examples:

EnsureSConsVersion(0,14)

EnsureSConsVersion(0,96,90)

Environment([key=value, ...]), env.Environment([key=value, ...])
Return a new construction environment initialized with the specified key=value pairs.

Execute(action, [strfunction, varlist]), env.Execute(action, [strfunction, varlist])
Executes an Action object. The specified action may be an Action object (see manpage
section "Action Objects" for an explanation of behavior), or it may be a command-line
string, list of commands, or executable Python function, each of which will be
converted into an Action object and then executed. Any additional arguments to Execute
(strfunction, varlist) are passed on to the Action factory function which actually
creates the Action object. The exit value of the command or return value of the Python
function will be returned.

Note that scons will print an error message if the executed action fails--that is,
exits with or returns a non-zero value. scons will not, however, automatically
terminate the build if the specified action fails. If you want the build to stop in
response to a failed Execute call, you must explicitly check for a non-zero return
value:

Execute(Copy('file.out', 'file.in'))

if Execute("mkdir sub/dir/ectory"):
# The mkdir failed, don't try to build.
Exit(1)

Exit([value]), env.Exit([value])
This tells scons to exit immediately with the specified value. A default exit value of
0 (zero) is used if no value is specified.

Export([vars...], [key=value...]), env.Export([vars...], [key=value...])
Exports variables from the current SConscript file to a global collection where they
can be imported by other SConscript files. vars may be one or more strings
representing variable names to be exported. If a string contains whitespace, it is
split into separate strings, as if multiple string arguments had been given. A vars
argument may also be a dictionary, which can be used to map variables to different
names when exported. Keyword arguments can be used to provide names and their values.

Export calls are cumulative. Specifying a previously exported variable will overwrite
the earlier value. Both local variables and global variables can be exported.

Examples:

env = Environment()
# Make env available for all SConscript files to Import().
Export("env")

package = 'my_name'
# Make env and package available for all SConscript files:.
Export("env", "package")

# Make env and package available for all SConscript files:
Export(["env", "package"])

# Make env available using the name debug:
Export(debug=env)

# Make env available using the name debug:
Export({"debug": env})

Note that the SConscript function supports an exports argument that allows exporting a
variable or set of variables to a specific SConscript file or files. See the
description below.

File(name, [directory]), env.File(name, [directory])
Returns File Node(s). A File Node is an object that represents a file. name can be a
relative or absolute path or a list of such paths. directory is an optional directory
that will be used as the parent directory. If no directory is specified, the current
script's directory is used as the parent.

If name is a single pathname, the corresponding node is returned. If name is a list,
SCons returns a list of nodes. Construction variables are expanded in name.

File Nodes can be used anywhere you would supply a string as a file name to a Builder
method or function. File Nodes have attributes and methods that are useful in many
situations; see manpage section "File and Directory Nodes" for more information.

FindFile(file, dirs), env.FindFile(file, dirs)
Search for file in the path specified by dirs. dirs may be a list of directory names
or a single directory name. In addition to searching for files that exist in the
filesystem, this function also searches for derived files that have not yet been
built.

Example:

foo = env.FindFile('foo', ['dir1', 'dir2'])

FindInstalledFiles(), env.FindInstalledFiles()
Returns the list of targets set up by the Install or InstallAs builders.

This function serves as a convenient method to select the contents of a binary
package.

Example:

Install( '/bin', [ 'executable_a', 'executable_b' ] )

# will return the file node list
# [ '/bin/executable_a', '/bin/executable_b' ]
FindInstalledFiles()

Install( '/lib', [ 'some_library' ] )

# will return the file node list
# [ '/bin/executable_a', '/bin/executable_b', '/lib/some_library' ]
FindInstalledFiles()

FindPathDirs(variable)
Returns a function (actually a callable Python object) intended to be used as the
path_function of a Scanner object. The returned object will look up the specified
variable in a construction environment and treat the construction variable's value as
a list of directory paths that should be searched (like $CPPPATH, $LIBPATH, etc.).

Note that use of FindPathDirs is generally preferable to writing your own
path_function for the following reasons: 1) The returned list will contain all
appropriate directories found in source trees (when VariantDir is used) or in code
repositories (when Repository or the -Y option are used). 2) scons will identify
expansions of variable that evaluate to the same list of directories as, in fact, the
same list, and avoid re-scanning the directories for files, when possible.

Example:

def my_scan(node, env, path, arg):
# Code to scan file contents goes here...
return include_files

scanner = Scanner(name = 'myscanner',
function = my_scan,
path_function = FindPathDirs('MYPATH'))

FindSourceFiles(node='"."'), env.FindSourceFiles(node='"."')
Returns the list of nodes which serve as the source of the built files. It does so by
inspecting the dependency tree starting at the optional argument node which defaults
to the '"."'-node. It will then return all leaves of node. These are all children
which have no further children.

This function is a convenient method to select the contents of a Source Package.

Example:

Program( 'src/main_a.c' )
Program( 'src/main_b.c' )
Program( 'main_c.c' )

# returns ['main_c.c', 'src/main_a.c', 'SConstruct', 'src/main_b.c']
FindSourceFiles()

# returns ['src/main_b.c', 'src/main_a.c' ]
FindSourceFiles( 'src' )

As you can see build support files (SConstruct in the above example) will also be
returned by this function.

Flatten(sequence), env.Flatten(sequence)
Takes a sequence (that is, a Python list or tuple) that may contain nested sequences
and returns a flattened list containing all of the individual elements in any
sequence. This can be helpful for collecting the lists returned by calls to Builders;
other Builders will automatically flatten lists specified as input, but direct Python
manipulation of these lists does not.

Examples:

foo = Object('foo.c')
bar = Object('bar.c')

# Because `foo' and `bar' are lists returned by the Object() Builder,
# `objects' will be a list containing nested lists:
objects = ['f1.o', foo, 'f2.o', bar, 'f3.o']

# Passing such a list to another Builder is all right because
# the Builder will flatten the list automatically:
Program(source = objects)

# If you need to manipulate the list directly using Python, you need to
# call Flatten() yourself, or otherwise handle nested lists:
for object in Flatten(objects):
print(str(object))

GetBuildFailures()
Returns a list of exceptions for the actions that failed while attempting to build
targets. Each element in the returned list is a BuildError object with the following
attributes that record various aspects of the build failure:

.node The node that was being built when the build failure occurred.

.status The numeric exit status returned by the command or Python function that failed
when trying to build the specified Node.

.errstr The SCons error string describing the build failure. (This is often a generic
message like "Error 2" to indicate that an executed command exited with a status of
2.)

.filename The name of the file or directory that actually caused the failure. This may
be different from the .node attribute. For example, if an attempt to build a target
named sub/dir/target fails because the sub/dir directory could not be created, then
the .node attribute will be sub/dir/target but the .filename attribute will be
sub/dir.

.executor The SCons Executor object for the target Node being built. This can be used
to retrieve the construction environment used for the failed action.

.action The actual SCons Action object that failed. This will be one specific action
out of the possible list of actions that would have been executed to build the target.

.command The actual expanded command that was executed and failed, after expansion of
$TARGET, $SOURCE, and other construction variables.

Note that the GetBuildFailures function will always return an empty list until any
build failure has occurred, which means that GetBuildFailures will always return an
empty list while the SConscript files are being read. Its primary intended use is for
functions that will be executed before SCons exits by passing them to the standard
Python atexit.register() function. Example:

import atexit

def print_build_failures():
from SCons.Script import GetBuildFailures
for bf in GetBuildFailures():
print("%s failed: %s" % (bf.node, bf.errstr))

atexit.register(print_build_failures)

GetBuildPath(file, [...]), env.GetBuildPath(file, [...])
Returns the scons path name (or names) for the specified file (or files). The
specified file or files may be scons Nodes or strings representing path names.

GetLaunchDir(), env.GetLaunchDir()
Returns the absolute path name of the directory from which scons was initially
invoked. This can be useful when using the -u, -U or -D options, which internally
change to the directory in which the SConstruct file is found.

GetOption(name), env.GetOption(name)
This function provides a way to query the value of SCons options set on scons command
line (or set using the SetOption function). The options supported are:

cache_debug
which corresponds to --cache-debug;

cache_disable
which corresponds to --cache-disable;

cache_force
which corresponds to --cache-force;

cache_show
which corresponds to --cache-show;

clean
which corresponds to -c, --clean and --remove;

config
which corresponds to --config;

directory
which corresponds to -C and --directory;

diskcheck
which corresponds to --diskcheck;

duplicate
which corresponds to --duplicate;

file
which corresponds to -f, --file, --makefile and --sconstruct;

help
which corresponds to -h and --help;

ignore_errors
which corresponds to --ignore-errors;

implicit_cache
which corresponds to --implicit-cache;

implicit_deps_changed
which corresponds to --implicit-deps-changed;

implicit_deps_unchanged
which corresponds to --implicit-deps-unchanged;

interactive
which corresponds to --interact and --interactive;

keep_going
which corresponds to -k and --keep-going;

max_drift
which corresponds to --max-drift;

no_exec
which corresponds to -n, --no-exec, --just-print, --dry-run and --recon;

no_site_dir
which corresponds to --no-site-dir;

num_jobs
which corresponds to -j and --jobs;

profile_file
which corresponds to --profile;

question
which corresponds to -q and --question;

random
which corresponds to --random;

repository
which corresponds to -Y, --repository and --srcdir;

silent
which corresponds to -s, --silent and --quiet;

site_dir
which corresponds to --site-dir;

stack_size
which corresponds to --stack-size;

taskmastertrace_file
which corresponds to --taskmastertrace; and

warn
which corresponds to --warn and --warning.

See the documentation for the corresponding command line option for information about
each specific option.

Glob(pattern, [ondisk, source, strings, exclude]), env.Glob(pattern, [ondisk, source,
strings, exclude])
Returns Nodes (or strings) that match the specified pattern, relative to the directory
of the current SConscript file. The evironment method form (env.Glob) performs string
substition on pattern and returns whatever matches the resulting expanded pattern.

The specified pattern uses Unix shell style metacharacters for matching:

* matches everything
? matches any single character
[seq] matches any character in seq
[!seq] matches any char not in seq

If the first character of a filename is a dot, it must be matched explicitly.
Character matches do not span directory separators.

The Glob knows about repositories (see the Repository function) and source directories
(see the VariantDir function) and returns a Node (or string, if so configured) in the
local (SConscript) directory if a matching Node is found anywhere in a corresponding
repository or source directory.

The ondisk argument may be set to a value which evaluates False to disable the search
for matches on disk, thereby only returning matches among already-configured File or
Dir Nodes. The default behavior is to return corresponding Nodes for any on-disk
matches found.

The source argument may be set to a value which evaluates True to specify that, when
the local directory is a VariantDir, the returned Nodes should be from the
corresponding source directory, not the local directory.

The strings argument may be set to a value which evaluates True to have the Glob
function return strings, not Nodes, that represent the matched files or directories.
The returned strings will be relative to the local (SConscript) directory. (Note that
This may make it easier to perform arbitrary manipulation of file names, but if the
returned strings are passed to a different SConscript file, any Node translation will
be relative to the other SConscript directory, not the original SConscript directory.)

The exclude argument may be set to a pattern or a list of patterns (following the same
Unix shell semantics) which must be filtered out of returned elements. Elements
matching a least one pattern of this list will be excluded.

Examples:

Program("foo", Glob("*.c"))
Zip("/tmp/everything", Glob(".??*") + Glob("*"))
sources = Glob("*.cpp", exclude=["os_*_specific_*.cpp"]) + \
Glob( "os_%s_specific_*.cpp" % currentOS)

Help(text, append=False), env.Help(text, append=False)
Specifies a local help message to be printed if the -h argument is given to scons.
Subsequent calls to Help append text to the previously defined local help text.

For the first call to Help only, if append is False (the default) any local help
message generated through AddOption calls is replaced. If append is True, text is
appended to the existing help text.

Ignore(target, dependency), env.Ignore(target, dependency)
The specified dependency file(s) will be ignored when deciding if the target file(s)
need to be rebuilt.

You can also use Ignore to remove a target from the default build. In order to do this
you must specify the directory the target will be built in as the target, and the file
you want to skip building as the dependency.

Note that this will only remove the dependencies listed from the files built by
default. It will still be built if that dependency is needed by another object being
built. See the third and forth examples below.

Examples:

env.Ignore('foo', 'foo.c')
env.Ignore('bar', ['bar1.h', 'bar2.h'])
env.Ignore('.','foobar.obj')
env.Ignore('bar','bar/foobar.obj')

Import(vars...), env.Import(vars...)
Imports variables into the current SConscript file. vars must be strings representing
names of variables which have been previously exported either by the Export function
or by the exports argument to SConscript. Variables exported by SConscript take
precedence. Multiple variable names can be passed to Import as separate arguments or
as words in a space-separated string. The wildcard "*" can be used to import all
available variables.

Examples:

Import("env")
Import("env", "variable")
Import(["env", "variable"])
Import("*")

Literal(string), env.Literal(string)
The specified string will be preserved as-is and not have construction variables
expanded.

Local(targets), env.Local(targets)
The specified targets will have copies made in the local tree, even if an already
up-to-date copy exists in a repository. Returns a list of the target Node or Nodes.

env.MergeFlags(arg, [unique])
Merges the specified arg values to the construction environment's construction
variables. If the arg argument is not a dictionary, it is converted to one by calling
env.ParseFlags on the argument before the values are merged. Note that arg must be a
single value, so multiple strings must be passed in as a list, not as separate
arguments to env.MergeFlags.

By default, duplicate values are eliminated; you can, however, specify unique=0 to
allow duplicate values to be added. When eliminating duplicate values, any
construction variables that end with the string PATH keep the left-most unique value.
All other construction variables keep the right-most unique value.

Examples:

# Add an optimization flag to $CCFLAGS.
env.MergeFlags('-O3')

# Combine the flags returned from running pkg-config with an optimization
# flag and merge the result into the construction variables.
env.MergeFlags(['!pkg-config gtk+-2.0 --cflags', '-O3'])

# Combine an optimization flag with the flags returned from running pkg-config
# twice and merge the result into the construction variables.
env.MergeFlags(['-O3',
'!pkg-config gtk+-2.0 --cflags --libs',
'!pkg-config libpng12 --cflags --libs'])

NoCache(target, ...), env.NoCache(target, ...)
Specifies a list of files which should not be cached whenever the CacheDir method has
been activated. The specified targets may be a list or an individual target.

Multiple files should be specified either as separate arguments to the NoCache method,
or as a list. NoCache will also accept the return value of any of the construction
environment Builder methods.

Calling NoCache on directories and other non-File Node types has no effect because
only File Nodes are cached.

Examples:

NoCache('foo.elf')
NoCache(env.Program('hello', 'hello.c'))

NoClean(target, ...), env.NoClean(target, ...)
Specifies a list of files or directories which should not be removed whenever the
targets (or their dependencies) are specified with the -c command line option. The
specified targets may be a list or an individual target. Multiple calls to NoClean are
legal, and prevent each specified target from being removed by calls to the -c option.

Multiple files or directories should be specified either as separate arguments to the
NoClean method, or as a list. NoClean will also accept the return value of any of the
construction environment Builder methods.

Calling NoClean for a target overrides calling Clean for the same target, and any
targets passed to both functions will not be removed by the -c option.

Examples:

NoClean('foo.elf')
NoClean(env.Program('hello', 'hello.c'))

env.ParseConfig(command, [function, unique])
Calls the specified function to modify the environment as specified by the output of
command. The default function is env.MergeFlags, which expects the output of a typical
*-config command (for example, gtk-config) and adds the options to the appropriate
construction variables. By default, duplicate values are not added to any construction
variables; you can specify unique=0 to allow duplicate values to be added.

Interpreted options and the construction variables they affect are as specified for
the env.ParseFlags method (which this method calls). See that method's description for
a table of options and construction variables.

ParseDepends(filename, [must_exist, only_one]), env.ParseDepends(filename, [must_exist,
only_one])
Parses the contents of the specified filename as a list of dependencies in the style
of Make or mkdep, and explicitly establishes all of the listed dependencies.

By default, it is not an error if the specified filename does not exist. The optional
must_exist argument may be set to a non-zero value to have scons throw an exception
and generate an error if the file does not exist, or is otherwise inaccessible.

The optional only_one argument may be set to a non-zero value to have scons thrown an
exception and generate an error if the file contains dependency information for more
than one target. This can provide a small sanity check for files intended to be
generated by, for example, the gcc -M flag, which should typically only write
dependency information for one output file into a corresponding .d file.

The filename and all of the files listed therein will be interpreted relative to the
directory of the SConscript file which calls the ParseDepends function.

env.ParseFlags(flags, ...)
Parses one or more strings containing typical command-line flags for GCC tool chains
and returns a dictionary with the flag values separated into the appropriate SCons
construction variables. This is intended as a companion to the env.MergeFlags method,
but allows for the values in the returned dictionary to be modified, if necessary,
before merging them into the construction environment. (Note that env.MergeFlags will
call this method if its argument is not a dictionary, so it is usually not necessary
to call env.ParseFlags directly unless you want to manipulate the values.)

If the first character in any string is an exclamation mark (!), the rest of the
string is executed as a command, and the output from the command is parsed as GCC tool
chain command-line flags and added to the resulting dictionary.

Flag values are translated accordig to the prefix found, and added to the following
construction variables:

-arch CCFLAGS, LINKFLAGS
-D CPPDEFINES
-framework FRAMEWORKS
-frameworkdir= FRAMEWORKPATH
-fmerge-all-constants CCFLAGS, LINKFLAGS
-fopenmp CCFLAGS, LINKFLAGS
-include CCFLAGS
-imacros CCFLAGS
-isysroot CCFLAGS, LINKFLAGS
-isystem CCFLAGS
-iquote CCFLAGS
-idirafter CCFLAGS
-I CPPPATH
-l LIBS
-L LIBPATH
-mno-cygwin CCFLAGS, LINKFLAGS
-mwindows LINKFLAGS
-openmp CCFLAGS, LINKFLAGS
-pthread CCFLAGS, LINKFLAGS
-std= CFLAGS
-Wa, ASFLAGS, CCFLAGS
-Wl,-rpath= RPATH
-Wl,-R, RPATH
-Wl,-R RPATH
-Wl, LINKFLAGS
-Wp, CPPFLAGS
- CCFLAGS
+ CCFLAGS, LINKFLAGS

Any other strings not associated with options are assumed to be the names of libraries
and added to the $LIBS construction variable.

Examples (all of which produce the same result):

dict = env.ParseFlags('-O2 -Dfoo -Dbar=1')
dict = env.ParseFlags('-O2', '-Dfoo', '-Dbar=1')
dict = env.ParseFlags(['-O2', '-Dfoo -Dbar=1'])
dict = env.ParseFlags('-O2', '!echo -Dfoo -Dbar=1')

Platform(string)
The Platform form returns a callable object that can be used to initialize a
construction environment using the platform keyword of the Environment function.

Example:

env = Environment(platform = Platform('win32'))

The env.Platform form applies the callable object for the specified platform string to
the environment through which the method was called.

env.Platform('posix')

Note that the win32 platform adds the SystemDrive and SystemRoot variables from the
user's external environment to the construction environment's $ENV dictionary. This is
so that any executed commands that use sockets to connect with other systems (such as
fetching source files from external CVS repository specifications like
:pserver:anonymous@cvs.sourceforge.net:/cvsroot/scons) will work on Windows systems.

Precious(target, ...), env.Precious(target, ...)
Marks each given target as precious so it is not deleted before it is rebuilt.
Normally scons deletes a target before building it. Multiple targets can be passed in
to a single call to Precious.

env.Prepend(key=val, [...])
Appends the specified keyword arguments to the beginning of construction variables in
the environment. If the Environment does not have the specified construction variable,
it is simply added to the environment. If the values of the construction variable and
the keyword argument are the same type, then the two values will be simply added
together. Otherwise, the construction variable and the value of the keyword argument
are both coerced to lists, and the lists are added together. (See also the Append
method, above.)

Example:

env.Prepend(CCFLAGS = '-g ', FOO = ['foo.yyy'])

env.PrependENVPath(name, newpath, [envname, sep, delete_existing])
This appends new path elements to the given path in the specified external environment
($ENV by default). This will only add any particular path once (leaving the first one
it encounters and ignoring the rest, to preserve path order), and to help assure this,
will normalize all paths (using os.path.normpath and os.path.normcase). This can also
handle the case where the given old path variable is a list instead of a string, in
which case a list will be returned instead of a string.

If delete_existing is 0, then adding a path that already exists will not move it to
the beginning; it will stay where it is in the list.

Example:

print 'before:',env['ENV']['INCLUDE']
include_path = '/foo/bar:/foo'
env.PrependENVPath('INCLUDE', include_path)
print 'after:',env['ENV']['INCLUDE']

The above example will print:

before: /biz:/foo
after: /foo/bar:/foo:/biz

env.PrependUnique(key=val, delete_existing=0, [...])
Appends the specified keyword arguments to the beginning of construction variables in
the environment. If the Environment does not have the specified construction variable,
it is simply added to the environment. If the construction variable being appended to
is a list, then any value(s) that already exist in the construction variable will not
be added again to the list. However, if delete_existing is 1, existing matching values
are removed first, so existing values in the arg list move to the front of the list.

Example:

env.PrependUnique(CCFLAGS = '-g', FOO = ['foo.yyy'])

Progress(callable, [interval]), Progress(string, [interval, file, overwrite]),
Progress(list_of_strings, [interval, file, overwrite])
Allows SCons to show progress made during the build by displaying a string or calling
a function while evaluating Nodes (e.g. files).

If the first specified argument is a Python callable (a function or an object that has
a __call__ method), the function will be called once every interval times a Node is
evaluated (default 1). The callable will be passed the evaluated Node as its only
argument. (For future compatibility, it's a good idea to also add *args and **kwargs
as arguments to your function or method signatures. This will prevent the code from
breaking if SCons ever changes the interface to call the function with additional
arguments in the future.)

An example of a simple custom progress function that prints a string containing the
Node name every 10 Nodes:

def my_progress_function(node, *args, **kwargs):
print('Evaluating node %s!' % node)
Progress(my_progress_function, interval=10)

A more complicated example of a custom progress display object that prints a string
containing a count every 100 evaluated Nodes. Note the use of \r (a carriage return)
at the end so that the string will overwrite itself on a display:

import sys
class ProgressCounter(object):
count = 0
def __call__(self, node, *args, **kw):
self.count += 100
sys.stderr.write('Evaluated %s nodes\r' % self.count)

Progress(ProgressCounter(), interval=100)

If the first argument to Progress is a string or list of strings, it is taken as text
to be displayed every interval evaluated Nodes. If the first argument is a list of
strings, then each string in the list will be displayed in rotating fashion every
interval evaluated Nodes.

The default is to print the string on standard output. An alternate output stream may
be specified with the file keyword argument, which the caller must pass already
opened.

The following will print a series of dots on the error output, one dot for every 100
evaluated Nodes:

import sys
Progress('.', interval=100, file=sys.stderr)

If the string contains the verbatim substring $TARGET;, it will be replaced with the
Node. Note that, for performance reasons, this is not a regular SCons variable
substition, so you can not use other variables or use curly braces. The following
example will print the name of every evaluated Node, using a carriage return) (\r) to
cause each line to overwritten by the next line, and the overwrite keyword argument
(default False) to make sure the previously-printed file name is overwritten with
blank spaces:

import sys
Progress('$TARGET\r', overwrite=True)

A list of strings can be used to implement a "spinner" on the user's screen as
follows, changing every five evaluated Nodes:

Progress(['-\r', '\\\r', '|\r', '/\r'], interval=5)

Pseudo(target, ...), env.Pseudo(target, ...)
This indicates that each given target should not be created by the build rule, and if
the target is created, an error will be generated. This is similar to the gnu make
.PHONY target. However, in the vast majority of cases, an Alias is more appropriate.
Multiple targets can be passed in to a single call to Pseudo.

PyPackageDir(modulename), env.PyPackageDir(modulename)
This returns a Directory Node similar to Dir. The python module / package is looked up
and if located the directory is returned for the location. modulename Is a named
python package / module to lookup the directory for it's location.

If modulename is a list, SCons returns a list of Dir nodes. Construction variables are
expanded in modulename.

env.Replace(key=val, [...])
Replaces construction variables in the Environment with the specified keyword
arguments.

Example:

env.Replace(CCFLAGS = '-g', FOO = 'foo.xxx')

Repository(directory), env.Repository(directory)
Specifies that directory is a repository to be searched for files. Multiple calls to
Repository are legal, and each one adds to the list of repositories that will be
searched.

To scons, a repository is a copy of the source tree, from the top-level directory on
down, which may contain both source files and derived files that can be used to build
targets in the local source tree. The canonical example would be an official source
tree maintained by an integrator. If the repository contains derived files, then the
derived files should have been built using scons, so that the repository contains the
necessary signature information to allow scons to figure out when it is appropriate to
use the repository copy of a derived file, instead of building one locally.

Note that if an up-to-date derived file already exists in a repository, scons will not
make a copy in the local directory tree. In order to guarantee that a local copy will
be made, use the Local method.

Requires(target, prerequisite), env.Requires(target, prerequisite)
Specifies an order-only relationship between the specified target file(s) and the
specified prerequisite file(s). The prerequisite file(s) will be (re)built, if
necessary, before the target file(s), but the target file(s) do not actually depend on
the prerequisites and will not be rebuilt simply because the prerequisite file(s)
change.

Example:

env.Requires('foo', 'file-that-must-be-built-before-foo')

Return([vars..., stop=True])
Return to the calling SConscript, optionally returning the values of variables named
in vars. Multiple strings contaning variable names may be passed to Return. A string
containing white space is split into individual variable names. Returns the value if
one variable is specified, else returns a tuple of values. Returns an empty tuple if
vars is omitted.

By default Return stops processing the current SConscript and returns immediately. The
optional stop keyword argument may be set to a false value to continue processing the
rest of the SConscript file after the Return call (this was the default behavior prior
to SCons 0.98.) However, the values returned are still the values of the variables in
the named vars at the point Return was called.

Examples:

# Returns no values (evaluates False)
Return()

# Returns the value of the 'foo' Python variable.
Return("foo")

# Returns the values of the Python variables 'foo' and 'bar'.
Return("foo", "bar")

# Returns the values of Python variables 'val1' and 'val2'.
Return('val1 val2')

Scanner(function, [argument, keys, path_function, node_class, node_factory, scan_check,
recursive]), env.Scanner(function, [argument, keys, path_function, node_class,
node_factory, scan_check, recursive])
Creates a Scanner object for the specified function. See manpage section "Scanner
Objects" for a complete explanation of the arguments and behavior.

SConscript(scripts, [exports, variant_dir, duplicate, must_exist]),
env.SConscript(scripts, [exports, variant_dir, duplicate, must_exist]),
SConscript(dirs=subdirs, [name=script, exports, variant_dir, duplicate, must_exist]),
env.SConscript(dirs=subdirs, [name=script, exports, variant_dir, duplicate, must_exist])
Execute one or more subsidiary SConscript (configuration) files. There are two ways to
call the SConscript function.

The first calling style is to explicitly specify one or more scripts as the first
argument. A single script may be specified as a string; multiple scripts must be
specified as a list (either explicitly or as created by a function like Split).
Examples:

SConscript('SConscript') # run SConscript in the current directory
SConscript('src/SConscript') # run SConscript in the src directory
SConscript(['src/SConscript', 'doc/SConscript'])
config = SConscript('MyConfig.py')

The second way to call SConscript is to specify a list of (sub)directory names as a
dirs=subdirs keyword argument. In this case, scons will execute a subsidiary
configuration file named SConscript in each of the specified directories. You may
specify a name other than SConscript by supplying an optional name=script keyword
argument. The first three examples below have the same effect as the first three
examples above:

SConscript(dirs='.') # run SConscript in the current directory
SConscript(dirs='src') # run SConscript in the src directory
SConscript(dirs=['src', 'doc'])
SConscript(dirs=['sub1', 'sub2'], name='MySConscript')

The optional exports argument provides a string or list of strings representing
variable names, or a dictionary of named values, to export. These variables are
locally exported only to the called SConscript file(s) and do not affect the global
pool of variables managed by the Export function. The subsidiary SConscript files
must use the Import function to import the variables. Examples:

foo = SConscript('sub/SConscript', exports='env')
SConscript('dir/SConscript', exports=['env', 'variable'])
SConscript(dirs='subdir', exports='env variable')
SConscript(dirs=['one', 'two', 'three'], exports='shared_info')

If the optional variant_dir argument is present, it causes an effect equivalent to the
VariantDir function. The variant_dir argument is interpreted relative to the directory
of the calling SConscript file. The optional duplicate argument is interpreted as for
VariantDir. If variant_dir is omitted, the duplicate argument is ignored. See the
description of VariantDir below for additional details and restrictions.

If variant_dir is present, the source directory is the directory in which the
SConscript file resides and the SConscript file is evaluated as if it were in the
variant_dir directory:

SConscript('src/SConscript', variant_dir='build')

is equivalent to

VariantDir('build', 'src')
SConscript('build/SConscript')

This later paradigm is often used when the sources are in the same directory as the
SConstruct:

SConscript('SConscript', variant_dir='build')

is equivalent to

VariantDir('build', '.')
SConscript('build/SConscript')

If the optional must_exist is True, causes an exception to be raised if a requested
SConscript file is not found. The current default is False, causing only a warning to
be emitted, but this default is deprecated (since 3.1). For scripts which truly intend
to be optional, transition to explicitly supplying must_exist=False to the SConscript
call.

Here are some composite examples:

# collect the configuration information and use it to build src and doc
shared_info = SConscript('MyConfig.py')
SConscript('src/SConscript', exports='shared_info')
SConscript('doc/SConscript', exports='shared_info')

# build debugging and production versions. SConscript
# can use Dir('.').path to determine variant.
SConscript('SConscript', variant_dir='debug', duplicate=0)
SConscript('SConscript', variant_dir='prod', duplicate=0)

# build debugging and production versions. SConscript
# is passed flags to use.
opts = { 'CPPDEFINES' : ['DEBUG'], 'CCFLAGS' : '-pgdb' }
SConscript('SConscript', variant_dir='debug', duplicate=0, exports=opts)
opts = { 'CPPDEFINES' : ['NODEBUG'], 'CCFLAGS' : '-O' }
SConscript('SConscript', variant_dir='prod', duplicate=0, exports=opts)

# build common documentation and compile for different architectures
SConscript('doc/SConscript', variant_dir='build/doc', duplicate=0)
SConscript('src/SConscript', variant_dir='build/x86', duplicate=0)
SConscript('src/SConscript', variant_dir='build/ppc', duplicate=0)

SConscript returns the values of any variables named by the executed SConscript(s) in
arguments to the Return function (see above for details). If a single SConscript call
causes multiple scripts to be executed, the return value is a tuple containing the
returns of all of the scripts. If an executed script does not explicitly call Return,
it returns None.

SConscriptChdir(value), env.SConscriptChdir(value)
By default, scons changes its working directory to the directory in which each
subsidiary SConscript file lives. This behavior may be disabled by specifying either:

SConscriptChdir(0)
env.SConscriptChdir(0)

in which case scons will stay in the top-level directory while reading all SConscript
files. (This may be necessary when building from repositories, when all the
directories in which SConscript files may be found don't necessarily exist locally.)
You may enable and disable this ability by calling SConscriptChdir() multiple times.

Example:

env = Environment()
SConscriptChdir(0)
SConscript('foo/SConscript') # will not chdir to foo
env.SConscriptChdir(1)
SConscript('bar/SConscript') # will chdir to bar

SConsignFile([file, dbm_module]), env.SConsignFile([file, dbm_module])
This tells scons to store all file signatures in the specified database file. If the
file name is omitted, .sconsign is used by default. (The actual file name(s) stored on
disk may have an appropriated suffix appended by the dbm_module.) If file is not an
absolute path name, the file is placed in the same directory as the top-level
SConstruct file.

If file is None, then scons will store file signatures in a separate .sconsign file in
each directory, not in one global database file. (This was the default behavior prior
to SCons 0.96.91 and 0.97.)

The optional dbm_module argument can be used to specify which Python database module
The default is to use a custom SCons.dblite module that uses pickled Python data
structures, and which works on all Python versions.

Examples:

# Explicitly stores signatures in ".sconsign.dblite"
# in the top-level SConstruct directory (the
# default behavior).
SConsignFile()

# Stores signatures in the file "etc/scons-signatures"
# relative to the top-level SConstruct directory.
SConsignFile("etc/scons-signatures")

# Stores signatures in the specified absolute file name.
SConsignFile("/home/me/SCons/signatures")

# Stores signatures in a separate .sconsign file
# in each directory.
SConsignFile(None)

env.SetDefault(key=val, [...])
Sets construction variables to default values specified with the keyword arguments if
(and only if) the variables are not already set. The following statements are
equivalent:

env.SetDefault(FOO = 'foo')

if 'FOO' not in env: env['FOO'] = 'foo'

SetOption(name, value), env.SetOption(name, value)
This function provides a way to set a select subset of the scons command line options
from a SConscript file. The options supported are:

clean
which corresponds to -c, --clean and --remove;

duplicate
which corresponds to --duplicate;

help
which corresponds to -h and --help;

implicit_cache
which corresponds to --implicit-cache;

max_drift
which corresponds to --max-drift;

no_exec
which corresponds to -n, --no-exec, --just-print, --dry-run and --recon;

num_jobs
which corresponds to -j and --jobs;

random
which corresponds to --random; and

silent
which corresponds to --silent.

no_progress
which corresponds to -Q.

Note: The initial progress output will still be output as this is done before the
SConstruct/SConscript which contains the SetOption is processed scons: Reading
SConscript files ...

Available since scons 4.0.

stack_size
which corresponds to --stack-size.

See the documentation for the corresponding command line option for information about
each specific option.

Example:

SetOption('max_drift', 1)

SideEffect(side_effect, target), env.SideEffect(side_effect, target)
Declares side_effect as a side effect of building target. Both side_effect and target
can be a list, a file name, or a node. A side effect is a target file that is created
or updated as a side effect of building other targets. For example, a Windows PDB file
is created as a side effect of building the .obj files for a static library, and
various log files are created updated as side effects of various TeX commands. If a
target is a side effect of multiple build commands, scons will ensure that only one
set of commands is executed at a time. Consequently, you only need to use this method
for side-effect targets that are built as a result of multiple build commands.

Because multiple build commands may update the same side effect file, by default the
side_effect target is not automatically removed when the target is removed by the -c
option. (Note, however, that the side_effect might be removed as part of cleaning the
directory in which it lives.) If you want to make sure the side_effect is cleaned
whenever a specific target is cleaned, you must specify this explicitly with the Clean
or env.Clean function.

Split(arg), env.Split(arg)
Returns a list of file names or other objects. If arg is a string, it will be split on
strings of white-space characters within the string, making it easier to write long
lists of file names. If arg is already a list, the list will be returned untouched. If
arg is any other type of object, it will be returned as a list containing just the
object.

Example:

files = Split("f1.c f2.c f3.c")
files = env.Split("f4.c f5.c f6.c")
files = Split("""
f7.c
f8.c
f9.c
""")

env.subst(input, [raw, target, source, conv])
Performs construction variable interpolation on the specified string or sequence
argument input.

By default, leading or trailing white space will be removed from the result. and all
sequences of white space will be compressed to a single space character. Additionally,
any $( and $) character sequences will be stripped from the returned string, The
optional raw argument may be set to 1 if you want to preserve white space and $(-$)
sequences. The raw argument may be set to 2 if you want to strip all characters
between any $( and $) pairs (as is done for signature calculation).

If the input is a sequence (list or tuple), the individual elements of the sequence
will be expanded, and the results will be returned as a list.

The optional target and source keyword arguments must be set to lists of target and
source nodes, respectively, if you want the $TARGET, $TARGETS, $SOURCE and $SOURCES to
be available for expansion. This is usually necessary if you are calling env.subst
from within a Python function used as an SCons action.

Returned string values or sequence elements are converted to their string
representation by default. The optional conv argument may specify a conversion
function that will be used in place of the default. For example, if you want Python
objects (including SCons Nodes) to be returned as Python objects, you can use the
Python Λ idiom to pass in an unnamed function that simply returns its unconverted
argument.

Example:

print(env.subst("The C compiler is: $CC"))

def compile(target, source, env):
sourceDir = env.subst("${SOURCE.srcdir}",
target=target,
source=source)

source_nodes = env.subst('$EXPAND_TO_NODELIST',
conv=lambda x: x)

Tag(node, tags)
Annotates file or directory Nodes with information about how the Package Builder
should package those files or directories. All tags are optional.

Examples:

# makes sure the built library will be installed with 0o644 file
# access mode
Tag( Library( 'lib.c' ), UNIX_ATTR="0o644" )

# marks file2.txt to be a documentation file
Tag( 'file2.txt', DOC )

Tool(name, [toolpath, **kwargs]), env.Tool(name, [toolpath, **kwargs])
Runs the tool identified by name, which is searched for in standard locations and any
paths specified by the optional toolpath, to update a construction environment with
construction variables needed to use the mechanisms that tool describes. Any
additional keyword arguments kwargs are passed on to the tool module's generate
function.

When called as a construction environment method, the tool module is called to update
the construction environment and the name of the tool is appended to the $TOOLS
construction variable in that environment.

Examples:

env.Tool('gcc')
env.Tool('opengl', toolpath=['build/tools'])

When called as a global function, returns a callable tool object; the tool is not
called at this time, as it lacks the context of an environment to update. This tool
object can be passed to an Environment or Clone call as part of the tools keyword
argument, or it can be called directly, passing a construction environment to update
as the argument. Either approach will also update the $TOOLS construction variable.

Examples:

env = Environment(tools=[Tool('msvc')])

env = Environment()
t = Tool('msvc')
t(env) # adds 'msvc' to the TOOLS variable
u = Tool('opengl', toolpath = ['tools'])
u(env) # adds 'opengl' to the TOOLS variable

Value(value, [built_value], [name]), env.Value(value, [built_value], [name])
Returns a Node object representing the specified Python value. Value Nodes can be used
as dependencies of targets. If the result of calling str(value) changes between SCons
runs, any targets depending on Value(value) will be rebuilt. (This is true even when
using timestamps to decide if files are up-to-date.) When using timestamp source
signatures, Value Nodes' timestamps are equal to the system time when the Node is
created. name can be provided as an alternative name for the resulting Value node;
this is advised if the value parameter can't be converted to a string.

The returned Value Node object has a write() method that can be used to "build" a
Value Node by setting a new value. The optional built_value argument can be specified
when the Value Node is created to indicate the Node should already be considered
"built." There is a corresponding read() method that will return the built value of
the Node.

Examples:

env = Environment()

def create(target, source, env):
# A function that will write a 'prefix=$SOURCE'
# string into the file name specified as the
# $TARGET.
f = open(str(target[0]), 'wb')
f.write('prefix=' + source[0].get_contents())

# Fetch the prefix= argument, if any, from the command
# line, and use /usr/local as the default.
prefix = ARGUMENTS.get('prefix', '/usr/local')

# Attach a .Config() builder for the above function action
# to the construction environment.
env['BUILDERS']['Config'] = Builder(action = create)
env.Config(target = 'package-config', source = Value(prefix))

def build_value(target, source, env):
# A function that "builds" a Python Value by updating
# the the Python value with the contents of the file
# specified as the source of the Builder call ($SOURCE).
target[0].write(source[0].get_contents())

output = env.Value('before')
input = env.Value('after')

# Attach a .UpdateValue() builder for the above function
# action to the construction environment.
env['BUILDERS']['UpdateValue'] = Builder(action = build_value)
env.UpdateValue(target = Value(output), source = Value(input))

VariantDir(variant_dir, src_dir, [duplicate]), env.VariantDir(variant_dir, src_dir,
[duplicate])
Use the VariantDir function to create a copy of your sources in another location: if a
name under variant_dir is not found but exists under src_dir, the file or directory is
copied to variant_dir. Target files can be built in a different directory than the
original sources by simply refering to the sources (and targets) within the variant
tree.

VariantDir can be called multiple times with the same src_dir to set up multiple
builds with different options (variants). The src_dir location must be in or
underneath the SConstruct file's directory, and variant_dir may not be underneath
src_dir.

The default behavior is for scons to physically duplicate the source files in the
variant tree. Thus, a build performed in the variant tree is guaranteed to be
identical to a build performed in the source tree even if intermediate source files
are generated during the build, or preprocessors or other scanners search for included
files relative to the source file, or individual compilers or other invoked tools are
hard-coded to put derived files in the same directory as source files.

If possible on the platform, the duplication is performed by linking rather than
copying; see also the --duplicate command-line option. Moreover, only the files needed
for the build are duplicated; files and directories that are not used are not present
in variant_dir.

Duplicating the source tree may be disabled by setting the duplicate argument to 0
(zero). This will cause scons to invoke Builders using the path names of source files
in src_dir and the path names of derived files within variant_dir. This is always more
efficient than duplicate=1, and is usually safe for most builds (but see above for
cases that may cause problems).

Note that VariantDir works most naturally with a subsidiary SConscript file. However,
you would then call the subsidiary SConscript file not in the source directory, but in
the variant_dir, regardless of the value of duplicate. This is how you tell scons
which variant of a source tree to build:

# run src/SConscript in two variant directories
VariantDir('build/variant1', 'src')
SConscript('build/variant1/SConscript')
VariantDir('build/variant2', 'src')
SConscript('build/variant2/SConscript')

See also the SConscript function, described above, for another way to specify a
variant directory in conjunction with calling a subsidiary SConscript file.

Examples:

# use names in the build directory, not the source directory
VariantDir('build', 'src', duplicate=0)
Program('build/prog', 'build/source.c')

# this builds both the source and docs in a separate subtree
VariantDir('build', '.', duplicate=0)
SConscript(dirs=['build/src','build/doc'])

# same as previous example, but only uses SConscript
SConscript(dirs='src', variant_dir='build/src', duplicate=0)
SConscript(dirs='doc', variant_dir='build/doc', duplicate=0)

WhereIs(program, [path, pathext, reject]), env.WhereIs(program, [path, pathext, reject])
Searches for the specified executable program, returning the full path to the program
or None.

When called as a construction environment method, searches the paths in the path
keyword argument, or if None (the default) the paths listed in the construction
environment (env['ENV']['PATH']). The external environment's path list
(os.environ['PATH']) is used as a fallback if the key env['ENV']['PATH'] does not
exist.

On Windows systems, searches for executable programs with any of the file extensions
listed in the pathext keyword argument, or if None (the default) the pathname
extensions listed in the construction environment (env['ENV']['PATHEXT']). The
external environment's pathname extensions list (os.environ['PATHEXT']) is used as a
fallback if the key env['ENV']['PATHEXT'] does not exist.

When called as a global function, uses the external environment's path
os.environ['PATH'] and path extensions os.environ['PATHEXT'], respectively, if path
and pathext are None.

Will not select any path name or names in the optional reject list.

SConscript Variables
In addition to the global functions and methods, scons supports a number of variables that
can be used in SConscript files to affect how you want the build to be performed.

ARGLIST
A list of the keyword=value arguments specified on the command line. Each element in
the list is a tuple containing the argument. The separate keyword and value elements
of the tuple can be accessed by subscripting for elements [0] and [1] of the tuple,
or, more readably, by using tuple unpacking. Example:

print("first keyword, value =", ARGLIST[0][0], ARGLIST[0][1])
print("second keyword, value =", ARGLIST[1][0], ARGLIST[1][1])
key, value = ARGLIST[2]
print("third keyword, value =", key, value)
for key, value in ARGLIST:
# process key and value

ARGUMENTS
A dictionary of all the keyword=value arguments specified on the command line. The
dictionary is not in order, and if a given keyword has more than one value assigned to
it on the command line, the last (right-most) value is the one in the ARGUMENTS
dictionary.

Example:

if ARGUMENTS.get('debug', 0):
env = Environment(CCFLAGS='-g')
else:
env = Environment()

BUILD_TARGETS
A list of the targets which scons has been asked to build. The contents will be either
those targets listed on the command line, or, if none, those targets set via calls to
the Default function. It does not contain any dependent targets that scons selects for
building as a result of making the sure the specified targets are up to date, if those
targets did not appear on the command line. The list is empty if neither command line
targets or Default calls are present.

The elements of this list may be strings or nodes, so you should run the list through
the Python str function to make sure any Node path names are converted to strings.

Because this list may be taken from the list of targets specified using the Default
function, the contents of the list may change on each successive call to Default. See
the DEFAULT_TARGETS list, below, for additional information.

Example:

if 'foo' in BUILD_TARGETS:
print("Don't forget to test the `foo' program!")
if 'special/program' in BUILD_TARGETS:
SConscript('special')

COMMAND_LINE_TARGETS
A list of the targets explicitly specified on the command line. If there are command
line targets, this list will have the same contents as BUILD_TARGETS. If there are no
targets specified on the command line, the list is empty. The elements of this list
are strings. This can be used, for example, to take specific actions only when certain
targets are explicitly being built.

Example:

if 'foo' in COMMAND_LINE_TARGETS:
print("Don't forget to test the `foo' program!")
if 'special/program' in COMMAND_LINE_TARGETS:
SConscript('special')

DEFAULT_TARGETS
A list of the target nodes that have been specified using the Default function. If
there are no command line targets, this list will have the same contents as
BUILD_TARGETS. Since the elements of the list are nodes, you need to call the Python
str function on them to get the path name for each Node.

Example:

print(str(DEFAULT_TARGETS[0]))
if 'foo' in [str(t) for t in DEFAULT_TARGETS]:
print("Don't forget to test the `foo' program!")

The contents of the DEFAULT_TARGETS list change on on each successive call to the
Default function:

print([str(t) for t in DEFAULT_TARGETS]) # originally []
Default('foo')
print([str(t) for t in DEFAULT_TARGETS]) # now a node ['foo']
Default('bar')
print([str(t) for t in DEFAULT_TARGETS]) # now a node ['foo', 'bar']
Default(None)
print([str(t) for t in DEFAULT_TARGETS]) # back to []

Consequently, be sure to use DEFAULT_TARGETS only after you've made all of your
Default() calls, or else simply be careful of the order of these statements in your
SConscript files so that you don't look for a specific default target before it's
actually been added to the list.

These variables may be accessed from custom Python modules that you import into an
SConscript file by adding the following to the Python module:

from SCons.Script import *

Construction Variables
A construction environment has an associated dictionary of construction variables that are
used by built-in or user-supplied build rules. Construction variable naming must follow
the same rules as for Python identifiers: the initial character must be an underscore or
letter, followed by any number of underscores, letters, or digits.

A construction environment is not a Python dictionary, but it can be indexed like one to
access a construction variable:

env["CC"] = "cc"

Construction variables can also be retrieved and set by using the Dictionary method of the
construction environment to create an actual dictionary:

cvars = env.Dictionary()
cvars["CC"] = "cc"

Construction variables can also be passed to the construction environment constructor:

env = Environment(CC="cc")

or when copying a construction environment using the Clone method:

env2 = env.Clone(CC="cl.exe")

A number of useful construction variables are automatically defined by scons for each
supported platform, and additional construction variables can be defined by the user. The
following is a list of the possible automatically defined construction variables. The
actual list available at execution time will not include all of these, as the ones
detected as not being useful (wrong platform, necessary external command or files not
installed, etc.) will not be set up. :

__LDMODULEVERSIONFLAGS
This construction variable automatically introduces $_LDMODULEVERSIONFLAGS if
$LDMODULEVERSION is set. Othervise it evaluates to an empty string.

__SHLIBVERSIONFLAGS
This construction variable automatically introduces $_SHLIBVERSIONFLAGS if
$SHLIBVERSION is set. Othervise it evaluates to an empty string.

APPLELINK_COMPATIBILITY_VERSION
On Mac OS X this is used to set the linker flag: -compatibility_version

The value is specified as X[.Y[.Z]] where X is between 1 and 65535, Y can be omitted
or between 1 and 255, Z can be omitted or between 1 and 255. This value will be
derived from $SHLIBVERSION if not specified. The lowest digit will be dropped and
replaced by a 0.

If the $APPLELINK_NO_COMPATIBILITY_VERSION is set then no -compatibility_version will
be output.

See MacOS's ld manpage for more details

_APPLELINK_COMPATIBILITY_VERSION
A macro (by default a generator function) used to create the linker flags to specify
apple's linker's -compatibility_version flag. The default generator uses
$APPLELINK_COMPATIBILITY_VERSION and $APPLELINK_NO_COMPATIBILITY_VERSION and
$SHLIBVERSION to determine the correct flag.

APPLELINK_CURRENT_VERSION
On Mac OS X this is used to set the linker flag: -current_version

The value is specified as X[.Y[.Z]] where X is between 1 and 65535, Y can be omitted
or between 1 and 255, Z can be omitted or between 1 and 255. This value will be set to
$SHLIBVERSION if not specified.

If the $APPLELINK_NO_CURRENT_VERSION is set then no -current_version will be output.

See MacOS's ld manpage for more details

_APPLELINK_CURRENT_VERSION
A macro (by default a generator function) used to create the linker flags to specify
apple's linker's -current_version flag. The default generator uses
$APPLELINK_CURRENT_VERSION and $APPLELINK_NO_CURRENT_VERSION and $SHLIBVERSION to
determine the correct flag.

APPLELINK_NO_COMPATIBILITY_VERSION
Set this to any True (1|True|non-empty string) value to disable adding
-compatibility_version flag when generating versioned shared libraries.

This overrides $APPLELINK_COMPATIBILITY_VERSION.

APPLELINK_NO_CURRENT_VERSION
Set this to any True (1|True|non-empty string) value to disable adding
-current_version flag when generating versioned shared libraries.

This overrides $APPLELINK_CURRENT_VERSION.

AR
The static library archiver.

ARCHITECTURE
Specifies the system architecture for which the package is being built. The default is
the system architecture of the machine on which SCons is running. This is used to fill
in the Architecture: field in an Ipkg control file, and the BuildArch: field in the
RPM .spec file, as well as forming part of the name of a generated RPM package file.

ARCOM
The command line used to generate a static library from object files.

ARCOMSTR
The string displayed when a static library is generated from object files. If this is
not set, then $ARCOM (the command line) is displayed.

env = Environment(ARCOMSTR = "Archiving $TARGET")

ARFLAGS
General options passed to the static library archiver.

AS
The assembler.

ASCOM
The command line used to generate an object file from an assembly-language source
file.

ASCOMSTR
The string displayed when an object file is generated from an assembly-language source
file. If this is not set, then $ASCOM (the command line) is displayed.

env = Environment(ASCOMSTR = "Assembling $TARGET")

ASFLAGS
General options passed to the assembler.

ASPPCOM
The command line used to assemble an assembly-language source file into an object file
after first running the file through the C preprocessor. Any options specified in the
$ASFLAGS and $CPPFLAGS construction variables are included on this command line.

ASPPCOMSTR
The string displayed when an object file is generated from an assembly-language source
file after first running the file through the C preprocessor. If this is not set, then
$ASPPCOM (the command line) is displayed.

env = Environment(ASPPCOMSTR = "Assembling $TARGET")

ASPPFLAGS
General options when an assembling an assembly-language source file into an object
file after first running the file through the C preprocessor. The default is to use
the value of $ASFLAGS.

BIBTEX
The bibliography generator for the TeX formatter and typesetter and the LaTeX
structured formatter and typesetter.

BIBTEXCOM
The command line used to call the bibliography generator for the TeX formatter and
typesetter and the LaTeX structured formatter and typesetter.

BIBTEXCOMSTR
The string displayed when generating a bibliography for TeX or LaTeX. If this is not
set, then $BIBTEXCOM (the command line) is displayed.

env = Environment(BIBTEXCOMSTR = "Generating bibliography $TARGET")

BIBTEXFLAGS
General options passed to the bibliography generator for the TeX formatter and
typesetter and the LaTeX structured formatter and typesetter.

BUILDERS
A dictionary mapping the names of the builders available through this environment to
underlying Builder objects. Builders named Alias, CFile, CXXFile, DVI, Library,
Object, PDF, PostScript, and Program are available by default. If you initialize this
variable when an Environment is created:

env = Environment(BUILDERS = {'NewBuilder' : foo})

the default Builders will no longer be available. To use a new Builder object in
addition to the default Builders, add your new Builder object like this:

env = Environment()
env.Append(BUILDERS = {'NewBuilder' : foo})

or this:

env = Environment()
env['BUILDERS']['NewBuilder'] = foo

CC
The C compiler.

CCCOM
The command line used to compile a C source file to a (static) object file. Any
options specified in the $CFLAGS, $CCFLAGS and $CPPFLAGS construction variables are
included on this command line. See also $SHCCCOM for compiling to shared objects.

CCCOMSTR
If set, the string displayed when a C source file is compiled to a (static) object
file. If not set, then $CCCOM (the command line) is displayed. See also $SHCCCOMSTR
for compiling to shared objects.

env = Environment(CCCOMSTR = "Compiling static object $TARGET")

CCFLAGS
General options that are passed to the C and C++ compilers. See also $SHCCFLAGS for
compiling to shared objects.

CCPCHFLAGS
Options added to the compiler command line to support building with precompiled
headers. The default value expands expands to the appropriate Microsoft Visual C++
command-line options when the $PCH construction variable is set.

CCPDBFLAGS
Options added to the compiler command line to support storing debugging information in
a Microsoft Visual C++ PDB file. The default value expands expands to appropriate
Microsoft Visual C++ command-line options when the $PDB construction variable is set.

The Visual C++ compiler option that SCons uses by default to generate PDB information
is /Z7. This works correctly with parallel (-j) builds because it embeds the debug
information in the intermediate object files, as opposed to sharing a single PDB file
between multiple object files. This is also the only way to get debug information
embedded into a static library. Using the /Zi instead may yield improved link-time
performance, although parallel builds will no longer work.

You can generate PDB files with the /Zi switch by overriding the default $CCPDBFLAGS
variable as follows:

env['CCPDBFLAGS'] = ['${(PDB and "/Zi /Fd%s" % File(PDB)) or ""}']

An alternative would be to use the /Zi to put the debugging information in a separate
.pdb file for each object file by overriding the $CCPDBFLAGS variable as follows:

env['CCPDBFLAGS'] = '/Zi /Fd${TARGET}.pdb'

CCVERSION
The version number of the C compiler. This may or may not be set, depending on the
specific C compiler being used.

CFILESUFFIX
The suffix for C source files. This is used by the internal CFile builder when
generating C files from Lex (.l) or YACC (.y) input files. The default suffix, of
course, is .c (lower case). On case-insensitive systems (like Windows), SCons also
treats .C (upper case) files as C files.

CFLAGS
General options that are passed to the C compiler (C only; not C++). See also
$SHCFLAGS for compiling to shared objects.

CHANGE_SPECFILE
A hook for modifying the file that controls the packaging build (the .spec for RPM,
the control for Ipkg, the .wxs for MSI). If set, the function will be called after the
SCons template for the file has been written.

CHANGED_SOURCES
A reserved variable name that may not be set or used in a construction environment.
(See the manpage section "Variable Substitution" for more information).

CHANGED_TARGETS
A reserved variable name that may not be set or used in a construction environment.
(See the manpage section "Variable Substitution" for more information).

CHANGELOG
The name of a file containing the change log text to be included in the package. This
is included as the %changelog section of the RPM .spec file.

COMPILATIONDB_COMSTR
The string displayed when CompilationDatabase builder's action is run.

COMPILATIONDB_USE_ABSPATH
This is a boolean flag to instruct CompilationDatabase to write the file and target
members in the compilation database with absolute or relative paths.

The default value is False (use relative paths)

_concat
A function used to produce variables like $_CPPINCFLAGS. It takes four or five
arguments: a prefix to concatenate onto each element, a list of elements, a suffix to
concatenate onto each element, an environment for variable interpolation, and an
optional function that will be called to transform the list before concatenation.

env['_CPPINCFLAGS'] = '$( ${_concat(INCPREFIX, CPPPATH, INCSUFFIX, __env__, RDirs)} $)',

CONFIGUREDIR
The name of the directory in which Configure context test files are written. The
default is .sconf_temp in the top-level directory containing the SConstruct file.

CONFIGURELOG
The name of the Configure context log file. The default is config.log in the top-level
directory containing the SConstruct file.

_CPPDEFFLAGS
An automatically-generated construction variable containing the C preprocessor
command-line options to define values. The value of $_CPPDEFFLAGS is created by
respectively prepending and appending $CPPDEFPREFIX and $CPPDEFSUFFIX to the beginning
and end of each definition in $CPPDEFINES.

CPPDEFINES
A platform independent specification of C preprocessor definitions. The definitions
will be added to command lines through the automatically-generated $_CPPDEFFLAGS
construction variable (see above), which is constructed according to the type of value
of $CPPDEFINES:

If $CPPDEFINES is a string, the values of the $CPPDEFPREFIX and $CPPDEFSUFFIX
construction variables will be respectively prepended and appended to the beginning
and end of each definition in $CPPDEFINES.

# Will add -Dxyz to POSIX compiler command lines,
# and /Dxyz to Microsoft Visual C++ command lines.
env = Environment(CPPDEFINES='xyz')

If $CPPDEFINES is a list, the values of the $CPPDEFPREFIX and $CPPDEFSUFFIX
construction variables will be respectively prepended and appended to the beginning
and end of each element in the list. If any element is a list or tuple, then the first
item is the name being defined and the second item is its value:

# Will add -DB=2 -DA to POSIX compiler command lines,
# and /DB=2 /DA to Microsoft Visual C++ command lines.
env = Environment(CPPDEFINES=[('B', 2), 'A'])

If $CPPDEFINES is a dictionary, the values of the $CPPDEFPREFIX and $CPPDEFSUFFIX
construction variables will be respectively prepended and appended to the beginning
and end of each item from the dictionary. The key of each dictionary item is a name
being defined to the dictionary item's corresponding value; if the value is None, then
the name is defined without an explicit value. Note that the resulting flags are
sorted by keyword to ensure that the order of the options on the command line is
consistent each time scons is run.

# Will add -DA -DB=2 to POSIX compiler command lines,
# and /DA /DB=2 to Microsoft Visual C++ command lines.
env = Environment(CPPDEFINES={'B':2, 'A':None})

CPPDEFPREFIX
The prefix used to specify preprocessor definitions on the C compiler command line.
This will be prepended to the beginning of each definition in the $CPPDEFINES
construction variable when the $_CPPDEFFLAGS variable is automatically generated.

CPPDEFSUFFIX
The suffix used to specify preprocessor definitions on the C compiler command line.
This will be appended to the end of each definition in the $CPPDEFINES construction
variable when the $_CPPDEFFLAGS variable is automatically generated.

CPPFLAGS
User-specified C preprocessor options. These will be included in any command that uses
the C preprocessor, including not just compilation of C and C++ source files via the
$CCCOM, $SHCCCOM, $CXXCOM and $SHCXXCOM command lines, but also the $FORTRANPPCOM,
$SHFORTRANPPCOM, $F77PPCOM and $SHF77PPCOM command lines used to compile a Fortran
source file, and the $ASPPCOM command line used to assemble an assembly language
source file, after first running each file through the C preprocessor. Note that this
variable does not contain -I (or similar) include search path options that scons
generates automatically from $CPPPATH. See $_CPPINCFLAGS, below, for the variable that
expands to those options.

_CPPINCFLAGS
An automatically-generated construction variable containing the C preprocessor
command-line options for specifying directories to be searched for include files. The
value of $_CPPINCFLAGS is created by respectively prepending and appending $INCPREFIX
and $INCSUFFIX to the beginning and end of each directory in $CPPPATH.

CPPPATH
The list of directories that the C preprocessor will search for include directories.
The C/C++ implicit dependency scanner will search these directories for include files.
Don't explicitly put include directory arguments in CCFLAGS or CXXFLAGS because the
result will be non-portable and the directories will not be searched by the dependency
scanner. Note: directory names in CPPPATH will be looked-up relative to the SConscript
directory when they are used in a command. To force scons to look-up a directory
relative to the root of the source tree use #:

env = Environment(CPPPATH='#/include')

The directory look-up can also be forced using the Dir() function:

include = Dir('include')
env = Environment(CPPPATH=include)

The directory list will be added to command lines through the automatically-generated
$_CPPINCFLAGS construction variable, which is constructed by respectively prepending
and appending the value of the $INCPREFIX and $INCSUFFIX construction variables to the
beginning and end of each directory in $CPPPATH. Any command lines you define that
need the CPPPATH directory list should include $_CPPINCFLAGS:

env = Environment(CCCOM="my_compiler $_CPPINCFLAGS -c -o $TARGET $SOURCE")

CPPSUFFIXES
The list of suffixes of files that will be scanned for C preprocessor implicit
dependencies (#include lines). The default list is:

[".c", ".C", ".cxx", ".cpp", ".c++", ".cc",
".h", ".H", ".hxx", ".hpp", ".hh",
".F", ".fpp", ".FPP",
".m", ".mm",
".S", ".spp", ".SPP"]

CXX
The C++ compiler. See also $SHCXX for compiling to shared objects..

CXXCOM
The command line used to compile a C++ source file to an object file. Any options
specified in the $CXXFLAGS and $CPPFLAGS construction variables are included on this
command line. See also $SHCXXCOM for compiling to shared objects..

CXXCOMSTR
If set, the string displayed when a C++ source file is compiled to a (static) object
file. If not set, then $CXXCOM (the command line) is displayed. See also $SHCXXCOMSTR
for compiling to shared objects..

env = Environment(CXXCOMSTR = "Compiling static object $TARGET")

CXXFILESUFFIX
The suffix for C++ source files. This is used by the internal CXXFile builder when
generating C++ files from Lex (.ll) or YACC (.yy) input files. The default suffix is
.cc. SCons also treats files with the suffixes .cpp, .cxx, .c++, and .C++ as C++
files, and files with .mm suffixes as Objective C++ files. On case-sensitive systems
(Linux, UNIX, and other POSIX-alikes), SCons also treats .C (upper case) files as C++
files.

CXXFLAGS
General options that are passed to the C++ compiler. By default, this includes the
value of $CCFLAGS, so that setting $CCFLAGS affects both C and C++ compilation. If you
want to add C++-specific flags, you must set or override the value of $CXXFLAGS. See
also $SHCXXFLAGS for compiling to shared objects..

CXXVERSION
The version number of the C++ compiler. This may or may not be set, depending on the
specific C++ compiler being used.

DC
The D compiler to use. See also $SHDC for compiling to shared objects.

DCOM
The command line used to compile a D file to an object file. Any options specified in
the $DFLAGS construction variable is included on this command line. See also $SHDCOM
for compiling to shared objects.

DCOMSTR
If set, the string displayed when a D source file is compiled to a (static) object
file. If not set, then $DCOM (the command line) is displayed. See also $SHDCOMSTR for
compiling to shared objects.

DDEBUG
List of debug tags to enable when compiling.

DDEBUGPREFIX
DDEBUGPREFIX.

DDEBUGSUFFIX
DDEBUGSUFFIX.

DESCRIPTION
A long description of the project being packaged. This is included in the relevant
section of the file that controls the packaging build.

DESCRIPTION_lang
A language-specific long description for the specified lang. This is used to populate
a %description -l section of an RPM .spec file.

DFILESUFFIX
DFILESUFFIX.

DFLAGPREFIX
DFLAGPREFIX.

DFLAGS
General options that are passed to the D compiler.

DFLAGSUFFIX
DFLAGSUFFIX.

DINCPREFIX
DINCPREFIX.

DINCSUFFIX
DLIBFLAGSUFFIX.

Dir
A function that converts a string into a Dir instance relative to the target being
built.

Dirs
A function that converts a list of strings into a list of Dir instances relative to
the target being built.

DLIB
Name of the lib tool to use for D codes.

DLIBCOM
The command line to use when creating libraries.

DLIBDIRPREFIX
DLIBLINKPREFIX.

DLIBDIRSUFFIX
DLIBLINKSUFFIX.

DLIBFLAGPREFIX
DLIBFLAGPREFIX.

DLIBFLAGSUFFIX
DLIBFLAGSUFFIX.

DLIBLINKPREFIX
DLIBLINKPREFIX.

DLIBLINKSUFFIX
DLIBLINKSUFFIX.

DLINK
Name of the linker to use for linking systems including D sources. See also $SHDLINK
for linking shared objects.

DLINKCOM
The command line to use when linking systems including D sources. See also $SHDLINKCOM
for linking shared objects.

DLINKFLAGPREFIX
DLINKFLAGPREFIX.

DLINKFLAGS
List of linker flags. See also $SHDLINKFLAGS for linking shared objects.

DLINKFLAGSUFFIX
DLINKFLAGSUFFIX.

DOCBOOK_DEFAULT_XSL_EPUB
The default XSLT file for the DocbookEpub builder within the current environment, if
no other XSLT gets specified via keyword.

DOCBOOK_DEFAULT_XSL_HTML
The default XSLT file for the DocbookHtml builder within the current environment, if
no other XSLT gets specified via keyword.

DOCBOOK_DEFAULT_XSL_HTMLCHUNKED
The default XSLT file for the DocbookHtmlChunked builder within the current
environment, if no other XSLT gets specified via keyword.

DOCBOOK_DEFAULT_XSL_HTMLHELP
The default XSLT file for the DocbookHtmlhelp builder within the current environment,
if no other XSLT gets specified via keyword.

DOCBOOK_DEFAULT_XSL_MAN
The default XSLT file for the DocbookMan builder within the current environment, if no
other XSLT gets specified via keyword.

DOCBOOK_DEFAULT_XSL_PDF
The default XSLT file for the DocbookPdf builder within the current environment, if no
other XSLT gets specified via keyword.

DOCBOOK_DEFAULT_XSL_SLIDESHTML
The default XSLT file for the DocbookSlidesHtml builder within the current
environment, if no other XSLT gets specified via keyword.

DOCBOOK_DEFAULT_XSL_SLIDESPDF
The default XSLT file for the DocbookSlidesPdf builder within the current environment,
if no other XSLT gets specified via keyword.

DOCBOOK_FOP
The path to the PDF renderer fop or xep, if one of them is installed (fop gets checked
first).

DOCBOOK_FOPCOM
The full command-line for the PDF renderer fop or xep.

DOCBOOK_FOPCOMSTR
The string displayed when a renderer like fop or xep is used to create PDF output from
an XML file.

DOCBOOK_FOPFLAGS
Additonal command-line flags for the PDF renderer fop or xep.

DOCBOOK_XMLLINT
The path to the external executable xmllint, if it's installed. Note, that this is
only used as last fallback for resolving XIncludes, if no lxml Python binding can be
imported in the current system.

DOCBOOK_XMLLINTCOM
The full command-line for the external executable xmllint.

DOCBOOK_XMLLINTCOMSTR
The string displayed when xmllint is used to resolve XIncludes for a given XML file.

DOCBOOK_XMLLINTFLAGS
Additonal command-line flags for the external executable xmllint.

DOCBOOK_XSLTPROC
The path to the external executable xsltproc (or saxon, xalan), if one of them is
installed. Note, that this is only used as last fallback for XSL transformations, if
no lxml Python binding can be imported in the current system.

DOCBOOK_XSLTPROCCOM
The full command-line for the external executable xsltproc (or saxon, xalan).

DOCBOOK_XSLTPROCCOMSTR
The string displayed when xsltproc is used to transform an XML file via a given XSLT
stylesheet.

DOCBOOK_XSLTPROCFLAGS
Additonal command-line flags for the external executable xsltproc (or saxon, xalan).

DOCBOOK_XSLTPROCPARAMS
Additonal parameters that are not intended for the XSLT processor executable, but the
XSL processing itself. By default, they get appended at the end of the command line
for saxon and saxon-xslt, respectively.

DPATH
List of paths to search for import modules.

DRPATHPREFIX
DRPATHPREFIX.

DRPATHSUFFIX
DRPATHSUFFIX.

DShLibSonameGenerator
DShLibSonameGenerator.

DSUFFIXES
The list of suffixes of files that will be scanned for imported D package files. The
default list is ['.d'].

DVERPREFIX
DVERPREFIX.

DVERSIONS
List of version tags to enable when compiling.

DVERSUFFIX
DVERSUFFIX.

DVIPDF
The TeX DVI file to PDF file converter.

DVIPDFCOM
The command line used to convert TeX DVI files into a PDF file.

DVIPDFCOMSTR
The string displayed when a TeX DVI file is converted into a PDF file. If this is not
set, then $DVIPDFCOM (the command line) is displayed.

DVIPDFFLAGS
General options passed to the TeX DVI file to PDF file converter.

DVIPS
The TeX DVI file to PostScript converter.

DVIPSFLAGS
General options passed to the TeX DVI file to PostScript converter.

ENV
A dictionary of environment variables to use when invoking commands. When $ENV is used
in a command all list values will be joined using the path separator and any other
non-string values will simply be coerced to a string. Note that, by default, scons
does not propagate the environment in force when you execute scons to the commands
used to build target files. This is so that builds will be guaranteed repeatable
regardless of the environment variables set at the time scons is invoked.

If you want to propagate your environment variables to the commands executed to build
target files, you must do so explicitly:

import os
env = Environment(ENV = os.environ)

Note that you can choose only to propagate certain environment variables. A common
example is the system PATH environment variable, so that scons uses the same utilities
as the invoking shell (or other process):

import os
env = Environment(ENV = {'PATH' : os.environ['PATH']})

ESCAPE
A function that will be called to escape shell special characters in command lines.
The function should take one argument: the command line string to escape; and should
return the escaped command line.

F03
The Fortran 03 compiler. You should normally set the $FORTRAN variable, which
specifies the default Fortran compiler for all Fortran versions. You only need to set
$F03 if you need to use a specific compiler or compiler version for Fortran 03 files.

F03COM
The command line used to compile a Fortran 03 source file to an object file. You only
need to set $F03COM if you need to use a specific command line for Fortran 03 files.
You should normally set the $FORTRANCOM variable, which specifies the default command
line for all Fortran versions.

F03COMSTR
If set, the string displayed when a Fortran 03 source file is compiled to an object
file. If not set, then $F03COM or $FORTRANCOM (the command line) is displayed.

F03FILESUFFIXES
The list of file extensions for which the F03 dialect will be used. By default, this
is ['.f03']

F03FLAGS
General user-specified options that are passed to the Fortran 03 compiler. Note that
this variable does not contain -I (or similar) include search path options that scons
generates automatically from $F03PATH. See $_F03INCFLAGS below, for the variable that
expands to those options. You only need to set $F03FLAGS if you need to define
specific user options for Fortran 03 files. You should normally set the $FORTRANFLAGS
variable, which specifies the user-specified options passed to the default Fortran
compiler for all Fortran versions.

_F03INCFLAGS
An automatically-generated construction variable containing the Fortran 03 compiler
command-line options for specifying directories to be searched for include files. The
value of $_F03INCFLAGS is created by appending $INCPREFIX and $INCSUFFIX to the
beginning and end of each directory in $F03PATH.

F03PATH
The list of directories that the Fortran 03 compiler will search for include
directories. The implicit dependency scanner will search these directories for include
files. Don't explicitly put include directory arguments in $F03FLAGS because the
result will be non-portable and the directories will not be searched by the dependency
scanner. Note: directory names in $F03PATH will be looked-up relative to the
SConscript directory when they are used in a command. To force scons to look-up a
directory relative to the root of the source tree use #: You only need to set $F03PATH
if you need to define a specific include path for Fortran 03 files. You should
normally set the $FORTRANPATH variable, which specifies the include path for the
default Fortran compiler for all Fortran versions.

env = Environment(F03PATH='#/include')

The directory look-up can also be forced using the Dir() function:

include = Dir('include')
env = Environment(F03PATH=include)

The directory list will be added to command lines through the automatically-generated
$_F03INCFLAGS construction variable, which is constructed by appending the values of
the $INCPREFIX and $INCSUFFIX construction variables to the beginning and end of each
directory in $F03PATH. Any command lines you define that need the F03PATH directory
list should include $_F03INCFLAGS:

env = Environment(F03COM="my_compiler $_F03INCFLAGS -c -o $TARGET $SOURCE")

F03PPCOM
The command line used to compile a Fortran 03 source file to an object file after
first running the file through the C preprocessor. Any options specified in the
$F03FLAGS and $CPPFLAGS construction variables are included on this command line. You
only need to set $F03PPCOM if you need to use a specific C-preprocessor command line
for Fortran 03 files. You should normally set the $FORTRANPPCOM variable, which
specifies the default C-preprocessor command line for all Fortran versions.

F03PPCOMSTR
If set, the string displayed when a Fortran 03 source file is compiled to an object
file after first running the file through the C preprocessor. If not set, then
$F03PPCOM or $FORTRANPPCOM (the command line) is displayed.

F03PPFILESUFFIXES
The list of file extensions for which the compilation + preprocessor pass for F03
dialect will be used. By default, this is empty

F08
The Fortran 08 compiler. You should normally set the $FORTRAN variable, which
specifies the default Fortran compiler for all Fortran versions. You only need to set
$F08 if you need to use a specific compiler or compiler version for Fortran 08 files.

F08COM
The command line used to compile a Fortran 08 source file to an object file. You only
need to set $F08COM if you need to use a specific command line for Fortran 08 files.
You should normally set the $FORTRANCOM variable, which specifies the default command
line for all Fortran versions.

F08COMSTR
If set, the string displayed when a Fortran 08 source file is compiled to an object
file. If not set, then $F08COM or $FORTRANCOM (the command line) is displayed.

F08FILESUFFIXES
The list of file extensions for which the F08 dialect will be used. By default, this
is ['.f08']

F08FLAGS
General user-specified options that are passed to the Fortran 08 compiler. Note that
this variable does not contain -I (or similar) include search path options that scons
generates automatically from $F08PATH. See $_F08INCFLAGS below, for the variable that
expands to those options. You only need to set $F08FLAGS if you need to define
specific user options for Fortran 08 files. You should normally set the $FORTRANFLAGS
variable, which specifies the user-specified options passed to the default Fortran
compiler for all Fortran versions.

_F08INCFLAGS
An automatically-generated construction variable containing the Fortran 08 compiler
command-line options for specifying directories to be searched for include files. The
value of $_F08INCFLAGS is created by appending $INCPREFIX and $INCSUFFIX to the
beginning and end of each directory in $F08PATH.

F08PATH
The list of directories that the Fortran 08 compiler will search for include
directories. The implicit dependency scanner will search these directories for include
files. Don't explicitly put include directory arguments in $F08FLAGS because the
result will be non-portable and the directories will not be searched by the dependency
scanner. Note: directory names in $F08PATH will be looked-up relative to the
SConscript directory when they are used in a command. To force scons to look-up a
directory relative to the root of the source tree use #: You only need to set $F08PATH
if you need to define a specific include path for Fortran 08 files. You should
normally set the $FORTRANPATH variable, which specifies the include path for the
default Fortran compiler for all Fortran versions.

env = Environment(F08PATH='#/include')

The directory look-up can also be forced using the Dir() function:

include = Dir('include')
env = Environment(F08PATH=include)

The directory list will be added to command lines through the automatically-generated
$_F08INCFLAGS construction variable, which is constructed by appending the values of
the $INCPREFIX and $INCSUFFIX construction variables to the beginning and end of each
directory in $F08PATH. Any command lines you define that need the F08PATH directory
list should include $_F08INCFLAGS:

env = Environment(F08COM="my_compiler $_F08INCFLAGS -c -o $TARGET $SOURCE")

F08PPCOM
The command line used to compile a Fortran 08 source file to an object file after
first running the file through the C preprocessor. Any options specified in the
$F08FLAGS and $CPPFLAGS construction variables are included on this command line. You
only need to set $F08PPCOM if you need to use a specific C-preprocessor command line
for Fortran 08 files. You should normally set the $FORTRANPPCOM variable, which
specifies the default C-preprocessor command line for all Fortran versions.

F08PPCOMSTR
If set, the string displayed when a Fortran 08 source file is compiled to an object
file after first running the file through the C preprocessor. If not set, then
$F08PPCOM or $FORTRANPPCOM (the command line) is displayed.

F08PPFILESUFFIXES
The list of file extensions for which the compilation + preprocessor pass for F08
dialect will be used. By default, this is empty

F77
The Fortran 77 compiler. You should normally set the $FORTRAN variable, which
specifies the default Fortran compiler for all Fortran versions. You only need to set
$F77 if you need to use a specific compiler or compiler version for Fortran 77 files.

F77COM
The command line used to compile a Fortran 77 source file to an object file. You only
need to set $F77COM if you need to use a specific command line for Fortran 77 files.
You should normally set the $FORTRANCOM variable, which specifies the default command
line for all Fortran versions.

F77COMSTR
If set, the string displayed when a Fortran 77 source file is compiled to an object
file. If not set, then $F77COM or $FORTRANCOM (the command line) is displayed.

F77FILESUFFIXES
The list of file extensions for which the F77 dialect will be used. By default, this
is ['.f77']

F77FLAGS
General user-specified options that are passed to the Fortran 77 compiler. Note that
this variable does not contain -I (or similar) include search path options that scons
generates automatically from $F77PATH. See $_F77INCFLAGS below, for the variable that
expands to those options. You only need to set $F77FLAGS if you need to define
specific user options for Fortran 77 files. You should normally set the $FORTRANFLAGS
variable, which specifies the user-specified options passed to the default Fortran
compiler for all Fortran versions.

_F77INCFLAGS
An automatically-generated construction variable containing the Fortran 77 compiler
command-line options for specifying directories to be searched for include files. The
value of $_F77INCFLAGS is created by appending $INCPREFIX and $INCSUFFIX to the
beginning and end of each directory in $F77PATH.

F77PATH
The list of directories that the Fortran 77 compiler will search for include
directories. The implicit dependency scanner will search these directories for include
files. Don't explicitly put include directory arguments in $F77FLAGS because the
result will be non-portable and the directories will not be searched by the dependency
scanner. Note: directory names in $F77PATH will be looked-up relative to the
SConscript directory when they are used in a command. To force scons to look-up a
directory relative to the root of the source tree use #: You only need to set $F77PATH
if you need to define a specific include path for Fortran 77 files. You should
normally set the $FORTRANPATH variable, which specifies the include path for the
default Fortran compiler for all Fortran versions.

env = Environment(F77PATH='#/include')

The directory look-up can also be forced using the Dir() function:

include = Dir('include')
env = Environment(F77PATH=include)

The directory list will be added to command lines through the automatically-generated
$_F77INCFLAGS construction variable, which is constructed by appending the values of
the $INCPREFIX and $INCSUFFIX construction variables to the beginning and end of each
directory in $F77PATH. Any command lines you define that need the F77PATH directory
list should include $_F77INCFLAGS:

env = Environment(F77COM="my_compiler $_F77INCFLAGS -c -o $TARGET $SOURCE")

F77PPCOM
The command line used to compile a Fortran 77 source file to an object file after
first running the file through the C preprocessor. Any options specified in the
$F77FLAGS and $CPPFLAGS construction variables are included on this command line. You
only need to set $F77PPCOM if you need to use a specific C-preprocessor command line
for Fortran 77 files. You should normally set the $FORTRANPPCOM variable, which
specifies the default C-preprocessor command line for all Fortran versions.

F77PPCOMSTR
If set, the string displayed when a Fortran 77 source file is compiled to an object
file after first running the file through the C preprocessor. If not set, then
$F77PPCOM or $FORTRANPPCOM (the command line) is displayed.

F77PPFILESUFFIXES
The list of file extensions for which the compilation + preprocessor pass for F77
dialect will be used. By default, this is empty

F90
The Fortran 90 compiler. You should normally set the $FORTRAN variable, which
specifies the default Fortran compiler for all Fortran versions. You only need to set
$F90 if you need to use a specific compiler or compiler version for Fortran 90 files.

F90COM
The command line used to compile a Fortran 90 source file to an object file. You only
need to set $F90COM if you need to use a specific command line for Fortran 90 files.
You should normally set the $FORTRANCOM variable, which specifies the default command
line for all Fortran versions.

F90COMSTR
If set, the string displayed when a Fortran 90 source file is compiled to an object
file. If not set, then $F90COM or $FORTRANCOM (the command line) is displayed.

F90FILESUFFIXES
The list of file extensions for which the F90 dialect will be used. By default, this
is ['.f90']

F90FLAGS
General user-specified options that are passed to the Fortran 90 compiler. Note that
this variable does not contain -I (or similar) include search path options that scons
generates automatically from $F90PATH. See $_F90INCFLAGS below, for the variable that
expands to those options. You only need to set $F90FLAGS if you need to define
specific user options for Fortran 90 files. You should normally set the $FORTRANFLAGS
variable, which specifies the user-specified options passed to the default Fortran
compiler for all Fortran versions.

_F90INCFLAGS
An automatically-generated construction variable containing the Fortran 90 compiler
command-line options for specifying directories to be searched for include files. The
value of $_F90INCFLAGS is created by appending $INCPREFIX and $INCSUFFIX to the
beginning and end of each directory in $F90PATH.

F90PATH
The list of directories that the Fortran 90 compiler will search for include
directories. The implicit dependency scanner will search these directories for include
files. Don't explicitly put include directory arguments in $F90FLAGS because the
result will be non-portable and the directories will not be searched by the dependency
scanner. Note: directory names in $F90PATH will be looked-up relative to the
SConscript directory when they are used in a command. To force scons to look-up a
directory relative to the root of the source tree use #: You only need to set $F90PATH
if you need to define a specific include path for Fortran 90 files. You should
normally set the $FORTRANPATH variable, which specifies the include path for the
default Fortran compiler for all Fortran versions.

env = Environment(F90PATH='#/include')

The directory look-up can also be forced using the Dir() function:

include = Dir('include')
env = Environment(F90PATH=include)

The directory list will be added to command lines through the automatically-generated
$_F90INCFLAGS construction variable, which is constructed by appending the values of
the $INCPREFIX and $INCSUFFIX construction variables to the beginning and end of each
directory in $F90PATH. Any command lines you define that need the F90PATH directory
list should include $_F90INCFLAGS:

env = Environment(F90COM="my_compiler $_F90INCFLAGS -c -o $TARGET $SOURCE")

F90PPCOM
The command line used to compile a Fortran 90 source file to an object file after
first running the file through the C preprocessor. Any options specified in the
$F90FLAGS and $CPPFLAGS construction variables are included on this command line. You
only need to set $F90PPCOM if you need to use a specific C-preprocessor command line
for Fortran 90 files. You should normally set the $FORTRANPPCOM variable, which
specifies the default C-preprocessor command line for all Fortran versions.

F90PPCOMSTR
If set, the string displayed when a Fortran 90 source file is compiled after first
running the file through the C preprocessor. If not set, then $F90PPCOM or
$FORTRANPPCOM (the command line) is displayed.

F90PPFILESUFFIXES
The list of file extensions for which the compilation + preprocessor pass for F90
dialect will be used. By default, this is empty

F95
The Fortran 95 compiler. You should normally set the $FORTRAN variable, which
specifies the default Fortran compiler for all Fortran versions. You only need to set
$F95 if you need to use a specific compiler or compiler version for Fortran 95 files.

F95COM
The command line used to compile a Fortran 95 source file to an object file. You only
need to set $F95COM if you need to use a specific command line for Fortran 95 files.
You should normally set the $FORTRANCOM variable, which specifies the default command
line for all Fortran versions.

F95COMSTR
If set, the string displayed when a Fortran 95 source file is compiled to an object
file. If not set, then $F95COM or $FORTRANCOM (the command line) is displayed.

F95FILESUFFIXES
The list of file extensions for which the F95 dialect will be used. By default, this
is ['.f95']

F95FLAGS
General user-specified options that are passed to the Fortran 95 compiler. Note that
this variable does not contain -I (or similar) include search path options that scons
generates automatically from $F95PATH. See $_F95INCFLAGS below, for the variable that
expands to those options. You only need to set $F95FLAGS if you need to define
specific user options for Fortran 95 files. You should normally set the $FORTRANFLAGS
variable, which specifies the user-specified options passed to the default Fortran
compiler for all Fortran versions.

_F95INCFLAGS
An automatically-generated construction variable containing the Fortran 95 compiler
command-line options for specifying directories to be searched for include files. The
value of $_F95INCFLAGS is created by appending $INCPREFIX and $INCSUFFIX to the
beginning and end of each directory in $F95PATH.

F95PATH
The list of directories that the Fortran 95 compiler will search for include
directories. The implicit dependency scanner will search these directories for include
files. Don't explicitly put include directory arguments in $F95FLAGS because the
result will be non-portable and the directories will not be searched by the dependency
scanner. Note: directory names in $F95PATH will be looked-up relative to the
SConscript directory when they are used in a command. To force scons to look-up a
directory relative to the root of the source tree use #: You only need to set $F95PATH
if you need to define a specific include path for Fortran 95 files. You should
normally set the $FORTRANPATH variable, which specifies the include path for the
default Fortran compiler for all Fortran versions.

env = Environment(F95PATH='#/include')

The directory look-up can also be forced using the Dir() function:

include = Dir('include')
env = Environment(F95PATH=include)

The directory list will be added to command lines through the automatically-generated
$_F95INCFLAGS construction variable, which is constructed by appending the values of
the $INCPREFIX and $INCSUFFIX construction variables to the beginning and end of each
directory in $F95PATH. Any command lines you define that need the F95PATH directory
list should include $_F95INCFLAGS:

env = Environment(F95COM="my_compiler $_F95INCFLAGS -c -o $TARGET $SOURCE")

F95PPCOM
The command line used to compile a Fortran 95 source file to an object file after
first running the file through the C preprocessor. Any options specified in the
$F95FLAGS and $CPPFLAGS construction variables are included on this command line. You
only need to set $F95PPCOM if you need to use a specific C-preprocessor command line
for Fortran 95 files. You should normally set the $FORTRANPPCOM variable, which
specifies the default C-preprocessor command line for all Fortran versions.

F95PPCOMSTR
If set, the string displayed when a Fortran 95 source file is compiled to an object
file after first running the file through the C preprocessor. If not set, then
$F95PPCOM or $FORTRANPPCOM (the command line) is displayed.

F95PPFILESUFFIXES
The list of file extensions for which the compilation + preprocessor pass for F95
dialect will be used. By default, this is empty

File
A function that converts a string into a File instance relative to the target being
built.

FORTRAN
The default Fortran compiler for all versions of Fortran.

FORTRANCOM
The command line used to compile a Fortran source file to an object file. By default,
any options specified in the $FORTRANFLAGS, $CPPFLAGS, $_CPPDEFFLAGS,
$_FORTRANMODFLAG, and $_FORTRANINCFLAGS construction variables are included on this
command line.

FORTRANCOMSTR
If set, the string displayed when a Fortran source file is compiled to an object file.
If not set, then $FORTRANCOM (the command line) is displayed.

FORTRANFILESUFFIXES
The list of file extensions for which the FORTRAN dialect will be used. By default,
this is ['.f', '.for', '.ftn']

FORTRANFLAGS
General user-specified options that are passed to the Fortran compiler. Note that this
variable does not contain -I (or similar) include or module search path options that
scons generates automatically from $FORTRANPATH. See $_FORTRANINCFLAGS and
$_FORTRANMODFLAG, below, for the variables that expand those options.

_FORTRANINCFLAGS
An automatically-generated construction variable containing the Fortran compiler
command-line options for specifying directories to be searched for include files and
module files. The value of $_FORTRANINCFLAGS is created by respectively prepending and
appending $INCPREFIX and $INCSUFFIX to the beginning and end of each directory in
$FORTRANPATH.

FORTRANMODDIR
Directory location where the Fortran compiler should place any module files it
generates. This variable is empty, by default. Some Fortran compilers will internally
append this directory in the search path for module files, as well.

FORTRANMODDIRPREFIX
The prefix used to specify a module directory on the Fortran compiler command line.
This will be prepended to the beginning of the directory in the $FORTRANMODDIR
construction variables when the $_FORTRANMODFLAG variables is automatically generated.

FORTRANMODDIRSUFFIX
The suffix used to specify a module directory on the Fortran compiler command line.
This will be appended to the end of the directory in the $FORTRANMODDIR construction
variables when the $_FORTRANMODFLAG variables is automatically generated.

_FORTRANMODFLAG
An automatically-generated construction variable containing the Fortran compiler
command-line option for specifying the directory location where the Fortran compiler
should place any module files that happen to get generated during compilation. The
value of $_FORTRANMODFLAG is created by respectively prepending and appending
$FORTRANMODDIRPREFIX and $FORTRANMODDIRSUFFIX to the beginning and end of the
directory in $FORTRANMODDIR.

FORTRANMODPREFIX
The module file prefix used by the Fortran compiler. SCons assumes that the Fortran
compiler follows the quasi-standard naming convention for module files of
module_name.mod. As a result, this variable is left empty, by default. For situations
in which the compiler does not necessarily follow the normal convention, the user may
use this variable. Its value will be appended to every module file name as scons
attempts to resolve dependencies.

FORTRANMODSUFFIX
The module file suffix used by the Fortran compiler. SCons assumes that the Fortran
compiler follows the quasi-standard naming convention for module files of
module_name.mod. As a result, this variable is set to ".mod", by default. For
situations in which the compiler does not necessarily follow the normal convention,
the user may use this variable. Its value will be appended to every module file name
as scons attempts to resolve dependencies.

FORTRANPATH
The list of directories that the Fortran compiler will search for include files and
(for some compilers) module files. The Fortran implicit dependency scanner will search
these directories for include files (but not module files since they are autogenerated
and, as such, may not actually exist at the time the scan takes place). Don't
explicitly put include directory arguments in FORTRANFLAGS because the result will be
non-portable and the directories will not be searched by the dependency scanner. Note:
directory names in FORTRANPATH will be looked-up relative to the SConscript directory
when they are used in a command. To force scons to look-up a directory relative to the
root of the source tree use #:

env = Environment(FORTRANPATH='#/include')

The directory look-up can also be forced using the Dir() function:

include = Dir('include')
env = Environment(FORTRANPATH=include)

The directory list will be added to command lines through the automatically-generated
$_FORTRANINCFLAGS construction variable, which is constructed by respectively
prepending and appending the values of the $INCPREFIX and $INCSUFFIX construction
variables to the beginning and end of each directory in $FORTRANPATH. Any command
lines you define that need the FORTRANPATH directory list should include
$_FORTRANINCFLAGS:

env = Environment(FORTRANCOM="my_compiler $_FORTRANINCFLAGS -c -o $TARGET $SOURCE")

FORTRANPPCOM
The command line used to compile a Fortran source file to an object file after first
running the file through the C preprocessor. By default, any options specified in the
$FORTRANFLAGS, $CPPFLAGS, $_CPPDEFFLAGS, $_FORTRANMODFLAG, and $_FORTRANINCFLAGS
construction variables are included on this command line.

FORTRANPPCOMSTR
If set, the string displayed when a Fortran source file is compiled to an object file
after first running the file through the C preprocessor. If not set, then
$FORTRANPPCOM (the command line) is displayed.

FORTRANPPFILESUFFIXES
The list of file extensions for which the compilation + preprocessor pass for FORTRAN
dialect will be used. By default, this is ['.fpp', '.FPP']

FORTRANSUFFIXES
The list of suffixes of files that will be scanned for Fortran implicit dependencies
(INCLUDE lines and USE statements). The default list is:

[".f", ".F", ".for", ".FOR", ".ftn", ".FTN", ".fpp", ".FPP",
".f77", ".F77", ".f90", ".F90", ".f95", ".F95"]

FRAMEWORKPATH
On Mac OS X with gcc, a list containing the paths to search for frameworks. Used by
the compiler to find framework-style includes like #include <Fmwk/Header.h>. Used by
the linker to find user-specified frameworks when linking (see $FRAMEWORKS). For
example:

env.AppendUnique(FRAMEWORKPATH='#myframeworkdir')

will add

... -Fmyframeworkdir

to the compiler and linker command lines.

_FRAMEWORKPATH
On Mac OS X with gcc, an automatically-generated construction variable containing the
linker command-line options corresponding to $FRAMEWORKPATH.

FRAMEWORKPATHPREFIX
On Mac OS X with gcc, the prefix to be used for the FRAMEWORKPATH entries. (see
$FRAMEWORKPATH). The default value is -F.

FRAMEWORKPREFIX
On Mac OS X with gcc, the prefix to be used for linking in frameworks (see
$FRAMEWORKS). The default value is -framework.

FRAMEWORKS
On Mac OS X with gcc, a list of the framework names to be linked into a program or
shared library or bundle. The default value is the empty list. For example:

env.AppendUnique(FRAMEWORKS=Split('System Cocoa SystemConfiguration'))

_FRAMEWORKS
On Mac OS X with gcc, an automatically-generated construction variable containing the
linker command-line options for linking with FRAMEWORKS.

FRAMEWORKSFLAGS
On Mac OS X with gcc, general user-supplied frameworks options to be added at the end
of a command line building a loadable module. (This has been largely superseded by the
$FRAMEWORKPATH, $FRAMEWORKPATHPREFIX, $FRAMEWORKPREFIX and $FRAMEWORKS variables
described above.)

GS
The Ghostscript program used, e.g. to convert PostScript to PDF files.

GSCOM
The full Ghostscript command line used for the conversion process. Its default value
is “$GS $GSFLAGS -sOutputFile=$TARGET $SOURCES”.

GSCOMSTR
The string displayed when Ghostscript is called for the conversion process. If this is
not set (the default), then $GSCOM (the command line) is displayed.

GSFLAGS
General options passed to the Ghostscript program, when converting PostScript to PDF
files for example. Its default value is “-dNOPAUSE -dBATCH -sDEVICE=pdfwrite”

HOST_ARCH
The name of the host hardware architecture used to create the Environment. If a
platform is specified when creating the Environment, then that Platform's logic will
handle setting this value. This value is immutable, and should not be changed by the
user after the Environment is initialized. Currently only set for Win32.

Sets the host architecture for Visual Studio compiler. If not set, default to the
detected host architecture: note that this may depend on the python you are using.
This variable must be passed as an argument to the Environment() constructor; setting
it later has no effect.

Valid values are the same as for $TARGET_ARCH.

This is currently only used on Windows, but in the future it may be used on other OSes
as well.

HOST_OS
The name of the host operating system used to create the Environment. If a platform is
specified when creating the Environment, then that Platform's logic will handle
setting this value. This value is immutable, and should not be changed by the user
after the Environment is initialized. Currently only set for Win32.

IDLSUFFIXES
The list of suffixes of files that will be scanned for IDL implicit dependencies
(#include or import lines). The default list is:

[".idl", ".IDL"]

IMPLIBNOVERSIONSYMLINKS
Used to override $SHLIBNOVERSIONSYMLINKS/$LDMODULENOVERSIONSYMLINKS when creating
versioned import library for a shared library/loadable module. If not defined, then
$SHLIBNOVERSIONSYMLINKS/$LDMODULENOVERSIONSYMLINKS is used to determine whether to
disable symlink generation or not.

IMPLIBPREFIX
The prefix used for import library names. For example, cygwin uses import libraries
(libfoo.dll.a) in pair with dynamic libraries (cygfoo.dll). The cyglink linker sets
$IMPLIBPREFIX to 'lib' and $SHLIBPREFIX to 'cyg'.

IMPLIBSUFFIX
The suffix used for import library names. For example, cygwin uses import libraries
(libfoo.dll.a) in pair with dynamic libraries (cygfoo.dll). The cyglink linker sets
$IMPLIBSUFFIX to '.dll.a' and $SHLIBSUFFIX to '.dll'.

IMPLIBVERSION
Used to override $SHLIBVERSION/$LDMODULEVERSION when generating versioned import
library for a shared library/loadable module. If undefined, the
$SHLIBVERSION/$LDMODULEVERSION is used to determine the version of versioned import
library.

IMPLICIT_COMMAND_DEPENDENCIES
Controls whether or not SCons will add implicit dependencies for the commands executed
to build targets.

By default, SCons will add to each target an implicit dependency on the command
represented by the first argument of any command line it executes (which is typically
the command itself). By setting such a dependency, SCons can determine that a target
should be rebuilt if the command changes, such as when a compiler is upgraded to a new
version. The specific file for the dependency is found by searching the PATH variable
in the ENV dictionary in the construction environment used to execute the command. The
default is the same as setting the construction variable
$IMPLICIT_COMMAND_DEPENDENCIES to a True-like value (“true”, “yes”, or “1” - but not a
number greater than one, as that has a different meaning).

Action strings can be segmented by the use of an AND operator, &&. In a segemented
string, each segment is a separate “command line”, these are run sequentially until
one fails or the entire sequence has been executed. If an action string is segmented,
then the selected behavior of $IMPLICIT_COMMAND_DEPENDENCIES is applied to each
segment.

If $IMPLICIT_COMMAND_DEPENDENCIES is set to a False-like value (“none”, “false”, “no”,
“0”, etc.), then the implicit dependency will not be added to the targets built with
that construction environment.

If $IMPLICIT_COMMAND_DEPENDENCIES is set to “2” or higher, then that number of
arguments in the command line will be scanned for relative or absolute paths. If any
are present, they will be added as implicit dependencies to the targets built with
that construction environment. The first argument in the command line will be searched
for using the PATH variable in the ENV dictionary in the construction environment used
to execute the command. The other arguments will only be found if they are absolute
paths or valid paths relative to the working directory.

If $IMPLICIT_COMMAND_DEPENDENCIES is set to “all”, then all arguments in the command
line will be scanned for relative or absolute paths. If any are present, they will be
added as implicit dependencies to the targets built with that construction
environment. The first argument in the command line will be searched for using the
PATH variable in the ENV dictionary in the construction environment used to execute
the command. The other arguments will only be found if they are absolute paths or
valid paths relative to the working directory.

env = Environment(IMPLICIT_COMMAND_DEPENDENCIES=False)

INCPREFIX
The prefix used to specify an include directory on the C compiler command line. This
will be prepended to the beginning of each directory in the $CPPPATH and $FORTRANPATH
construction variables when the $_CPPINCFLAGS and $_FORTRANINCFLAGS variables are
automatically generated.

INCSUFFIX
The suffix used to specify an include directory on the C compiler command line. This
will be appended to the end of each directory in the $CPPPATH and $FORTRANPATH
construction variables when the $_CPPINCFLAGS and $_FORTRANINCFLAGS variables are
automatically generated.

INSTALL
A function to be called to install a file into a destination file name. The default
function copies the file into the destination (and sets the destination file's mode
and permission bits to match the source file's). The function takes the following
arguments:

def install(dest, source, env):

dest is the path name of the destination file. source is the path name of the source
file. env is the construction environment (a dictionary of construction values) in
force for this file installation.

INSTALLSTR
The string displayed when a file is installed into a destination file name. The
default is:

Install file: "$SOURCE" as "$TARGET"

INTEL_C_COMPILER_VERSION
Set by the "intelc" Tool to the major version number of the Intel C compiler selected
for use.

JAR
The Java archive tool.

JARCHDIR
The directory to which the Java archive tool should change (using the -C option).

JARCOM
The command line used to call the Java archive tool.

JARCOMSTR
The string displayed when the Java archive tool is called If this is not set, then
$JARCOM (the command line) is displayed.

env = Environment(JARCOMSTR="JARchiving $SOURCES into $TARGET")

JARFLAGS
General options passed to the Java archive tool. By default this is set to cf to
create the necessary jar file.

JARSUFFIX
The suffix for Java archives: .jar by default.

JAVABOOTCLASSPATH
Specifies the list of directories that will be added to the javac command line via the
-bootclasspath option. The individual directory names will be separated by the
operating system's path separate character (: on UNIX/Linux/POSIX, ; on Windows).

JAVAC
The Java compiler.

JAVACCOM
The command line used to compile a directory tree containing Java source files to
corresponding Java class files. Any options specified in the $JAVACFLAGS construction
variable are included on this command line.

JAVACCOMSTR
The string displayed when compiling a directory tree of Java source files to
corresponding Java class files. If this is not set, then $JAVACCOM (the command line)
is displayed.

env = Environment(JAVACCOMSTR="Compiling class files $TARGETS from $SOURCES")

JAVACFLAGS
General options that are passed to the Java compiler.

JAVACLASSDIR
The directory in which Java class files may be found. This is stripped from the
beginning of any Java .class file names supplied to the JavaH builder.

JAVACLASSPATH
Specifies the list of directories that will be searched for Java .class file. The
directories in this list will be added to the javac and javah command lines via the
-classpath option. The individual directory names will be separated by the operating
system's path separate character (: on UNIX/Linux/POSIX, ; on Windows).

Note that this currently just adds the specified directory via the -classpath option.
SCons does not currently search the $JAVACLASSPATH directories for dependency .class
files.

JAVACLASSSUFFIX
The suffix for Java class files; .class by default.

JAVAH
The Java generator for C header and stub files.

JAVAHCOM
The command line used to generate C header and stub files from Java classes. Any
options specified in the $JAVAHFLAGS construction variable are included on this
command line.

JAVAHCOMSTR
The string displayed when C header and stub files are generated from Java classes. If
this is not set, then $JAVAHCOM (the command line) is displayed.

env = Environment(JAVAHCOMSTR="Generating header/stub file(s) $TARGETS from $SOURCES")

JAVAHFLAGS
General options passed to the C header and stub file generator for Java classes.

JAVAINCLUDES
Include path for Java header files (such as jni.h)

JAVASOURCEPATH
Specifies the list of directories that will be searched for input .java file. The
directories in this list will be added to the javac command line via the -sourcepath
option. The individual directory names will be separated by the operating system's
path separate character (: on UNIX/Linux/POSIX, ; on Windows).

Note that this currently just adds the specified directory via the -sourcepath option.
SCons does not currently search the $JAVASOURCEPATH directories for dependency .java
files.

JAVASUFFIX
The suffix for Java files; .java by default.

JAVAVERSION
Specifies the Java version being used by the Java builder. This is not currently used
to select one version of the Java compiler vs. another. Instead, you should set this
to specify the version of Java supported by your javac compiler. The default is 1.4.

This is sometimes necessary because Java 1.5 changed the file names that are created
for nested anonymous inner classes, which can cause a mismatch with the files that
SCons expects will be generated by the javac compiler. Setting $JAVAVERSION to 1.5 (or
1.6, as appropriate) can make SCons realize that a Java 1.5 or 1.6 build is actually
up to date.

LATEX
The LaTeX structured formatter and typesetter.

LATEXCOM
The command line used to call the LaTeX structured formatter and typesetter.

LATEXCOMSTR
The string displayed when calling the LaTeX structured formatter and typesetter. If
this is not set, then $LATEXCOM (the command line) is displayed.

env = Environment(LATEXCOMSTR = "Building $TARGET from LaTeX input $SOURCES")

LATEXFLAGS
General options passed to the LaTeX structured formatter and typesetter.

LATEXRETRIES
The maximum number of times that LaTeX will be re-run if the .log generated by the
$LATEXCOM command indicates that there are undefined references. The default is to try
to resolve undefined references by re-running LaTeX up to three times.

LATEXSUFFIXES
The list of suffixes of files that will be scanned for LaTeX implicit dependencies
(\include or \import files). The default list is:

[".tex", ".ltx", ".latex"]

LDMODULE
The linker for building loadable modules. By default, this is the same as $SHLINK.

LDMODULECOM
The command line for building loadable modules. On Mac OS X, this uses the $LDMODULE,
$LDMODULEFLAGS and $FRAMEWORKSFLAGS variables. On other systems, this is the same as
$SHLINK.

LDMODULECOMSTR
If set, the string displayed when building loadable modules. If not set, then
$LDMODULECOM (the command line) is displayed.

LDMODULEEMITTER
Contains the emitter specification for the LoadableModule builder. The manpage section
"Builder Objects" contains general information on specifying emitters.

LDMODULEFLAGS
General user options passed to the linker for building loadable modules.

LDMODULENOVERSIONSYMLINKS
Instructs the LoadableModule builder to not automatically create symlinks for
versioned modules. Defaults to $SHLIBNOVERSIONSYMLINKS

LDMODULEPREFIX
The prefix used for loadable module file names. On Mac OS X, this is null; on other
systems, this is the same as $SHLIBPREFIX.

_LDMODULESONAME
A macro that automatically generates loadable module's SONAME based on $TARGET,
$LDMODULEVERSION and $LDMODULESUFFIX. Used by LoadableModule builder when the linker
tool supports SONAME (e.g. gnulink).

LDMODULESUFFIX
The suffix used for loadable module file names. On Mac OS X, this is null; on other
systems, this is the same as $SHLIBSUFFIX.

LDMODULEVERSION
When this construction variable is defined, a versioned loadable module is created by
LoadableModule builder. This activates the $_LDMODULEVERSIONFLAGS and thus modifies
the $LDMODULECOM as required, adds the version number to the library name, and creates
the symlinks that are needed. $LDMODULEVERSION versions should exist in the same
format as $SHLIBVERSION.

_LDMODULEVERSIONFLAGS
This macro automatically introduces extra flags to $LDMODULECOM when building
versioned LoadableModule (that is when $LDMODULEVERSION is set).
_LDMODULEVERSIONFLAGS usually adds $SHLIBVERSIONFLAGS and some extra dynamically
generated options (such as -Wl,-soname=$_LDMODULESONAME). It is unused by plain
(unversioned) loadable modules.

LDMODULEVERSIONFLAGS
Extra flags added to $LDMODULECOM when building versioned LoadableModule. These flags
are only used when $LDMODULEVERSION is set.

LEX
The lexical analyzer generator.

LEXCOM
The command line used to call the lexical analyzer generator to generate a source
file.

LEXCOMSTR
The string displayed when generating a source file using the lexical analyzer
generator. If this is not set, then $LEXCOM (the command line) is displayed.

env = Environment(LEXCOMSTR = "Lex'ing $TARGET from $SOURCES")

LEXFLAGS
General options passed to the lexical analyzer generator.

LEXUNISTD
Used only on windows environments to set a lex flag to prevent 'unistd.h' from being
included. The default value is '--nounistd'.

_LIBDIRFLAGS
An automatically-generated construction variable containing the linker command-line
options for specifying directories to be searched for library. The value of
$_LIBDIRFLAGS is created by respectively prepending and appending $LIBDIRPREFIX and
$LIBDIRSUFFIX to the beginning and end of each directory in $LIBPATH.

LIBDIRPREFIX
The prefix used to specify a library directory on the linker command line. This will
be prepended to the beginning of each directory in the $LIBPATH construction variable
when the $_LIBDIRFLAGS variable is automatically generated.

LIBDIRSUFFIX
The suffix used to specify a library directory on the linker command line. This will
be appended to the end of each directory in the $LIBPATH construction variable when
the $_LIBDIRFLAGS variable is automatically generated.

LIBEMITTER
Contains the emitter specification for the StaticLibrary builder. The manpage section
"Builder Objects" contains general information on specifying emitters.

_LIBFLAGS
An automatically-generated construction variable containing the linker command-line
options for specifying libraries to be linked with the resulting target. The value of
$_LIBFLAGS is created by respectively prepending and appending $LIBLINKPREFIX and
$LIBLINKSUFFIX to the beginning and end of each filename in $LIBS.

LIBLINKPREFIX
The prefix used to specify a library to link on the linker command line. This will be
prepended to the beginning of each library in the $LIBS construction variable when the
$_LIBFLAGS variable is automatically generated.

LIBLINKSUFFIX
The suffix used to specify a library to link on the linker command line. This will be
appended to the end of each library in the $LIBS construction variable when the
$_LIBFLAGS variable is automatically generated.

LIBPATH
The list of directories that will be searched for libraries. The implicit dependency
scanner will search these directories for include files. Don't explicitly put include
directory arguments in $LINKFLAGS or $SHLINKFLAGS because the result will be
non-portable and the directories will not be searched by the dependency scanner. Note:
directory names in LIBPATH will be looked-up relative to the SConscript directory when
they are used in a command. To force scons to look-up a directory relative to the root
of the source tree use #:

env = Environment(LIBPATH='#/libs')

The directory look-up can also be forced using the Dir() function:

libs = Dir('libs')
env = Environment(LIBPATH=libs)

The directory list will be added to command lines through the automatically-generated
$_LIBDIRFLAGS construction variable, which is constructed by respectively prepending
and appending the values of the $LIBDIRPREFIX and $LIBDIRSUFFIX construction variables
to the beginning and end of each directory in $LIBPATH. Any command lines you define
that need the LIBPATH directory list should include $_LIBDIRFLAGS:

env = Environment(LINKCOM="my_linker $_LIBDIRFLAGS $_LIBFLAGS -o $TARGET $SOURCE")

LIBPREFIX
The prefix used for (static) library file names. A default value is set for each
platform (posix, win32, os2, etc.), but the value is overridden by individual tools
(ar, mslib, sgiar, sunar, tlib, etc.) to reflect the names of the libraries they
create.

LIBPREFIXES
A list of all legal prefixes for library file names. When searching for library
dependencies, SCons will look for files with these prefixes, the base library name,
and suffixes in the $LIBSUFFIXES list.

LIBS
A list of one or more libraries that will be linked with any executable programs
created by this environment.

The library list will be added to command lines through the automatically-generated
$_LIBFLAGS construction variable, which is constructed by respectively prepending and
appending the values of the $LIBLINKPREFIX and $LIBLINKSUFFIX construction variables
to the beginning and end of each filename in $LIBS. Any command lines you define that
need the LIBS library list should include $_LIBFLAGS:

env = Environment(LINKCOM="my_linker $_LIBDIRFLAGS $_LIBFLAGS -o $TARGET $SOURCE")

If you add a File object to the $LIBS list, the name of that file will be added to
$_LIBFLAGS, and thus the link line, as is, without $LIBLINKPREFIX or $LIBLINKSUFFIX.
For example:

env.Append(LIBS=File('/tmp/mylib.so'))

In all cases, scons will add dependencies from the executable program to all the
libraries in this list.

LIBSUFFIX
The suffix used for (static) library file names. A default value is set for each
platform (posix, win32, os2, etc.), but the value is overridden by individual tools
(ar, mslib, sgiar, sunar, tlib, etc.) to reflect the names of the libraries they
create.

LIBSUFFIXES
A list of all legal suffixes for library file names. When searching for library
dependencies, SCons will look for files with prefixes, in the $LIBPREFIXES list, the
base library name, and these suffixes.

LICENSE
The abbreviated name, preferably the SPDX code, of the license under which this
project is released (GPL-3.0, LGPL-2.1, BSD-2-Clause etc.). See
http://www.opensource.org/licenses/alphabetical for a list of license names and SPDX
codes.

LINESEPARATOR
The separator used by the Substfile and Textfile builders. This value is used between
sources when constructing the target. It defaults to the current system line
separator.

LINGUAS_FILE
The $LINGUAS_FILE defines file(s) containing list of additional linguas to be
processed by POInit, POUpdate or MOFiles builders. It also affects Translate builder.
If the variable contains a string, it defines name of the list file. The $LINGUAS_FILE
may be a list of file names as well. If $LINGUAS_FILE is set to True (or non-zero
numeric value), the list will be read from default file named LINGUAS.

LINK
The linker. See also $SHLINK for linking shared objects.

LINKCOM
The command line used to link object files into an executable. See also $SHLINKCOM for
linking shared objects.

LINKCOMSTR
If set, the string displayed when object files are linked into an executable. If not
set, then $LINKCOM (the command line) is displayed. See also $SHLINKCOMSTR. for
linking shared objects.

env = Environment(LINKCOMSTR = "Linking $TARGET")

LINKFLAGS
General user options passed to the linker. Note that this variable should not contain
-l (or similar) options for linking with the libraries listed in $LIBS, nor -L (or
similar) library search path options that scons generates automatically from $LIBPATH.
See $_LIBFLAGS above, for the variable that expands to library-link options, and
$_LIBDIRFLAGS above, for the variable that expands to library search path options. See
also $SHLINKFLAGS. for linking shared objects.

M4
The M4 macro preprocessor.

M4COM
The command line used to pass files through the M4 macro preprocessor.

M4COMSTR
The string displayed when a file is passed through the M4 macro preprocessor. If this
is not set, then $M4COM (the command line) is displayed.

M4FLAGS
General options passed to the M4 macro preprocessor.

MAKEINDEX
The makeindex generator for the TeX formatter and typesetter and the LaTeX structured
formatter and typesetter.

MAKEINDEXCOM
The command line used to call the makeindex generator for the TeX formatter and
typesetter and the LaTeX structured formatter and typesetter.

MAKEINDEXCOMSTR
The string displayed when calling the makeindex generator for the TeX formatter and
typesetter and the LaTeX structured formatter and typesetter. If this is not set, then
$MAKEINDEXCOM (the command line) is displayed.

MAKEINDEXFLAGS
General options passed to the makeindex generator for the TeX formatter and typesetter
and the LaTeX structured formatter and typesetter.

MAXLINELENGTH
The maximum number of characters allowed on an external command line. On Win32
systems, link lines longer than this many characters are linked via a temporary file
name.

MIDL
The Microsoft IDL compiler.

MIDLCOM
The command line used to pass files to the Microsoft IDL compiler.

MIDLCOMSTR
The string displayed when the Microsoft IDL compiler is called. If this is not set,
then $MIDLCOM (the command line) is displayed.

MIDLFLAGS
General options passed to the Microsoft IDL compiler.

MOSUFFIX
Suffix used for MO files (default: '.mo'). See msgfmt tool and MOFiles builder.

MSGFMT
Absolute path to msgfmt(1) binary, found by Detect(). See msgfmt tool and MOFiles
builder.

MSGFMTCOM
Complete command line to run msgfmt(1) program. See msgfmt tool and MOFiles builder.

MSGFMTCOMSTR
String to display when msgfmt(1) is invoked (default: '', which means ``print
$MSGFMTCOM''). See msgfmt tool and MOFiles builder.

MSGFMTFLAGS
Additional flags to msgfmt(1). See msgfmt tool and MOFiles builder.

MSGINIT
Path to msginit(1) program (found via Detect()). See msginit tool and POInit builder.

MSGINITCOM
Complete command line to run msginit(1) program. See msginit tool and POInit builder.

MSGINITCOMSTR
String to display when msginit(1) is invoked (default: '', which means ``print
$MSGINITCOM''). See msginit tool and POInit builder.

MSGINITFLAGS
List of additional flags to msginit(1) (default: []). See msginit tool and POInit
builder.

_MSGINITLOCALE
Internal ``macro''. Computes locale (language) name based on target filename (default:
'${TARGET.filebase}').

See msginit tool and POInit builder.

MSGMERGE
Absolute path to msgmerge(1) binary as found by Detect(). See msgmerge tool and
POUpdate builder.

MSGMERGECOM
Complete command line to run msgmerge(1) command. See msgmerge tool and POUpdate
builder.

MSGMERGECOMSTR
String to be displayed when msgmerge(1) is invoked (default: '', which means ``print
$MSGMERGECOM''). See msgmerge tool and POUpdate builder.

MSGMERGEFLAGS
Additional flags to msgmerge(1) command. See msgmerge tool and POUpdate builder.

MSSDK_DIR
The directory containing the Microsoft SDK (either Platform SDK or Windows SDK) to be
used for compilation.

MSSDK_VERSION
The version string of the Microsoft SDK (either Platform SDK or Windows SDK) to be
used for compilation. Supported versions include 6.1, 6.0A, 6.0, 2003R2 and 2003R1.

MSVC_BATCH
When set to any true value, specifies that SCons should batch compilation of object
files when calling the Microsoft Visual C/C++ compiler. All compilations of source
files from the same source directory that generate target files in a same output
directory and were configured in SCons using the same construction environment will be
built in a single call to the compiler. Only source files that have changed since
their object files were built will be passed to each compiler invocation (via the
$CHANGED_SOURCES construction variable). Any compilations where the object (target)
file base name (minus the .obj) does not match the source file base name will be
compiled separately.

MSVC_USE_SCRIPT
Use a batch script to set up Microsoft Visual Studio compiler.

If set to the name of a Visual Studio .bat file (e.g. vcvars.bat), SCons will run
that batch file instead of the auto-detected one, and extract the relevant variables
from the result (typically %INCLUDE%, %LIB%, and %PATH%) for supplying to the build.
This can be useful to force the use of a compiler version that SCons does not detect.

Setting $MSVC_USE_SCRIPT to None bypasses the Visual Studio autodetection entirely;
use this if you are running SCons in a Visual Studio cmd window and importing the
shell's environment variables - that is, if you are sure everything is set correctly
already and you don't want SCons to change anything.

$MSVC_USE_SCRIPT overrides $MSVC_VERSION and $TARGET_ARCH.

MSVC_UWP_APP
Build libraries for a Universal Windows Platform (UWP) Application.

If $MSVC_UWP_APP is set, the Visual Studio environment will be set up to point to the
Windows Store compatible libraries and Visual Studio runtimes. In doing so, any
libraries that are built will be able to be used in a UWP App and published to the
Windows Store. This flag will only have an effect with Visual Studio 2015 or later.
This variable must be passed as an argument to the Environment() constructor; setting
it later has no effect.

Valid values are '1' or '0'

MSVC_VERSION
Sets the preferred version of Microsoft Visual C/C++ to use.

If $MSVC_VERSION is not set, SCons will (by default) select the latest version of
Visual C/C++ installed on your system. If the specified version isn't installed, tool
initialization will fail. This variable must be passed as an argument to the
Environment() constructor; setting it later has no effect.

Valid values for Windows are 14.2, 14.1, 14.1Exp, 14.0, 14.0Exp, 12.0, 12.0Exp, 11.0,
11.0Exp, 10.0, 10.0Exp, 9.0, 9.0Exp, 8.0, 8.0Exp, 7.1, 7.0, and 6.0. Versions ending
in Exp refer to "Express" or "Express for Desktop" editions.

MSVS
When the Microsoft Visual Studio tools are initialized, they set up this dictionary
with the following keys:

VERSION
the version of MSVS being used (can be set via $MSVS_VERSION)

VERSIONS
the available versions of MSVS installed

VCINSTALLDIR
installed directory of Visual C++

VSINSTALLDIR
installed directory of Visual Studio

FRAMEWORKDIR
installed directory of the .NET framework

FRAMEWORKVERSIONS
list of installed versions of the .NET framework, sorted latest to oldest.

FRAMEWORKVERSION
latest installed version of the .NET framework

FRAMEWORKSDKDIR
installed location of the .NET SDK.

PLATFORMSDKDIR
installed location of the Platform SDK.

PLATFORMSDK_MODULES
dictionary of installed Platform SDK modules, where the dictionary keys are
keywords for the various modules, and the values are 2-tuples where the first is
the release date, and the second is the version number.

If a value is not set, it was not available in the registry.

MSVS_ARCH
Sets the architecture for which the generated project(s) should build.

The default value is x86. amd64 is also supported by SCons for most Visual Studio
versions. Since Visual Studio 2015 arm is supported, and since Visual Studio 2017
arm64 is supported. Trying to set $MSVS_ARCH to an architecture that's not supported
for a given Visual Studio version will generate an error.

MSVS_PROJECT_GUID
The string placed in a generated Microsoft Visual Studio project file as the value of
the ProjectGUID attribute. There is no default value. If not defined, a new GUID is
generated.

MSVS_SCC_AUX_PATH
The path name placed in a generated Microsoft Visual Studio project file as the value
of the SccAuxPath attribute if the MSVS_SCC_PROVIDER construction variable is also
set. There is no default value.

MSVS_SCC_CONNECTION_ROOT
The root path of projects in your SCC workspace, i.e the path under which all project
and solution files will be generated. It is used as a reference path from which the
relative paths of the generated Microsoft Visual Studio project and solution files are
computed. The relative project file path is placed as the value of the SccLocalPath
attribute of the project file and as the values of the
SccProjectFilePathRelativizedFromConnection[i] (where [i] ranges from 0 to the number
of projects in the solution) attributes of the GlobalSection(SourceCodeControl)
section of the Microsoft Visual Studio solution file. Similarly the relative solution
file path is placed as the values of the SccLocalPath[i] (where [i] ranges from 0 to
the number of projects in the solution) attributes of the
GlobalSection(SourceCodeControl) section of the Microsoft Visual Studio solution file.
This is used only if the MSVS_SCC_PROVIDER construction variable is also set. The
default value is the current working directory.

MSVS_SCC_PROJECT_NAME
The project name placed in a generated Microsoft Visual Studio project file as the
value of the SccProjectName attribute if the MSVS_SCC_PROVIDER construction variable
is also set. In this case the string is also placed in the SccProjectName0 attribute
of the GlobalSection(SourceCodeControl) section of the Microsoft Visual Studio
solution file. There is no default value.

MSVS_SCC_PROVIDER
The string placed in a generated Microsoft Visual Studio project file as the value of
the SccProvider attribute. The string is also placed in the SccProvider0 attribute of
the GlobalSection(SourceCodeControl) section of the Microsoft Visual Studio solution
file. There is no default value.

MSVS_VERSION
Sets the preferred version of Microsoft Visual Studio to use.

If $MSVS_VERSION is not set, SCons will (by default) select the latest version of
Visual Studio installed on your system. So, if you have version 6 and version 7 (MSVS
.NET) installed, it will prefer version 7. You can override this by specifying the
MSVS_VERSION variable in the Environment initialization, setting it to the appropriate
version ('6.0' or '7.0', for example). If the specified version isn't installed, tool
initialization will fail.

This is obsolete: use $MSVC_VERSION instead. If $MSVS_VERSION is set and $MSVC_VERSION
is not, $MSVC_VERSION will be set automatically to $MSVS_VERSION. If both are set to
different values, scons will raise an error.

MSVSBUILDCOM
The build command line placed in a generated Microsoft Visual Studio project file. The
default is to have Visual Studio invoke SCons with any specified build targets.

MSVSCLEANCOM
The clean command line placed in a generated Microsoft Visual Studio project file. The
default is to have Visual Studio invoke SCons with the -c option to remove any
specified targets.

MSVSENCODING
The encoding string placed in a generated Microsoft Visual Studio project file. The
default is encoding Windows-1252.

MSVSPROJECTCOM
The action used to generate Microsoft Visual Studio project files.

MSVSPROJECTSUFFIX
The suffix used for Microsoft Visual Studio project (DSP) files. The default value is
.vcproj when using Visual Studio version 7.x (.NET) or later version, and .dsp when
using earlier versions of Visual Studio.

MSVSREBUILDCOM
The rebuild command line placed in a generated Microsoft Visual Studio project file.
The default is to have Visual Studio invoke SCons with any specified rebuild targets.

MSVSSCONS
The SCons used in generated Microsoft Visual Studio project files. The default is the
version of SCons being used to generate the project file.

MSVSSCONSCOM
The default SCons command used in generated Microsoft Visual Studio project files.

MSVSSCONSCRIPT
The sconscript file (that is, SConstruct or SConscript file) that will be invoked by
Visual Studio project files (through the $MSVSSCONSCOM variable). The default is the
same sconscript file that contains the call to MSVSProject to build the project file.

MSVSSCONSFLAGS
The SCons flags used in generated Microsoft Visual Studio project files.

MSVSSOLUTIONCOM
The action used to generate Microsoft Visual Studio solution files.

MSVSSOLUTIONSUFFIX
The suffix used for Microsoft Visual Studio solution (DSW) files. The default value is
.sln when using Visual Studio version 7.x (.NET), and .dsw when using earlier versions
of Visual Studio.

MT
The program used on Windows systems to embed manifests into DLLs and EXEs. See also
$WINDOWS_EMBED_MANIFEST.

MTEXECOM
The Windows command line used to embed manifests into executables. See also
$MTSHLIBCOM.

MTFLAGS
Flags passed to the $MT manifest embedding program (Windows only).

MTSHLIBCOM
The Windows command line used to embed manifests into shared libraries (DLLs). See
also $MTEXECOM.

MWCW_VERSION
The version number of the MetroWerks CodeWarrior C compiler to be used.

MWCW_VERSIONS
A list of installed versions of the MetroWerks CodeWarrior C compiler on this system.

NAME
Specfies the name of the project to package.

no_import_lib
When set to non-zero, suppresses creation of a corresponding Windows static import lib
by the SharedLibrary builder when used with MinGW, Microsoft Visual Studio or
Metrowerks. This also suppresses creation of an export (.exp) file when using
Microsoft Visual Studio.

OBJPREFIX
The prefix used for (static) object file names.

OBJSUFFIX
The suffix used for (static) object file names.

PACKAGEROOT
Specifies the directory where all files in resulting archive will be placed if
applicable. The default value is "$NAME-$VERSION".

PACKAGETYPE
Selects the package type to build. Currently these are available:
msi - Microsoft Installer
rpm - RPM Package Manger
ipkg - Itsy Package Management System
tarbz2 - bzip2 compressed tar
targz - gzip compressed tar
tarxz - xz compressed tar
zip - zip file
src_tarbz2 - bzip2 compressed tar source
src_targz - gzip compressed tar source
src_tarxz - xz compressed tar source
src_zip - zip file source
This may be overridden with the package_type command line option.

PACKAGEVERSION
The version of the package (not the underlying project). This is currently only used
by the rpm packager and should reflect changes in the packaging, not the underlying
project code itself.

PCH
The Microsoft Visual C++ precompiled header that will be used when compiling object
files. This variable is ignored by tools other than Microsoft Visual C++. When this
variable is defined SCons will add options to the compiler command line to cause it to
use the precompiled header, and will also set up the dependencies for the PCH file.
Example:

env['PCH'] = 'StdAfx.pch'

PCHCOM
The command line used by the PCH builder to generated a precompiled header.

PCHCOMSTR
The string displayed when generating a precompiled header. If this is not set, then
$PCHCOM (the command line) is displayed.

PCHPDBFLAGS
A construction variable that, when expanded, adds the /yD flag to the command line
only if the $PDB construction variable is set.

PCHSTOP
This variable specifies how much of a source file is precompiled. This variable is
ignored by tools other than Microsoft Visual C++, or when the PCH variable is not
being used. When this variable is define it must be a string that is the name of the
header that is included at the end of the precompiled portion of the source files, or
the empty string if the "#pragma hrdstop" construct is being used:

env['PCHSTOP'] = 'StdAfx.h'

PDB
The Microsoft Visual C++ PDB file that will store debugging information for object
files, shared libraries, and programs. This variable is ignored by tools other than
Microsoft Visual C++. When this variable is defined SCons will add options to the
compiler and linker command line to cause them to generate external debugging
information, and will also set up the dependencies for the PDB file. Example:

env['PDB'] = 'hello.pdb'

The Visual C++ compiler switch that SCons uses by default to generate PDB information
is /Z7. This works correctly with parallel (-j) builds because it embeds the debug
information in the intermediate object files, as opposed to sharing a single PDB file
between multiple object files. This is also the only way to get debug information
embedded into a static library. Using the /Zi instead may yield improved link-time
performance, although parallel builds will no longer work. You can generate PDB files
with the /Zi switch by overriding the default $CCPDBFLAGS variable; see the entry for
that variable for specific examples.

PDFCOM
A deprecated synonym for $DVIPDFCOM.

PDFLATEX
The pdflatex utility.

PDFLATEXCOM
The command line used to call the pdflatex utility.

PDFLATEXCOMSTR
The string displayed when calling the pdflatex utility. If this is not set, then
$PDFLATEXCOM (the command line) is displayed.

env = Environment(PDFLATEX;COMSTR = "Building $TARGET from LaTeX input $SOURCES")

PDFLATEXFLAGS
General options passed to the pdflatex utility.

PDFPREFIX
The prefix used for PDF file names.

PDFSUFFIX
The suffix used for PDF file names.

PDFTEX
The pdftex utility.

PDFTEXCOM
The command line used to call the pdftex utility.

PDFTEXCOMSTR
The string displayed when calling the pdftex utility. If this is not set, then
$PDFTEXCOM (the command line) is displayed.

env = Environment(PDFTEXCOMSTR = "Building $TARGET from TeX input $SOURCES")

PDFTEXFLAGS
General options passed to the pdftex utility.

PKGCHK
On Solaris systems, the package-checking program that will be used (along with
$PKGINFO) to look for installed versions of the Sun PRO C++ compiler. The default is
/usr/sbin/pgkchk.

PKGINFO
On Solaris systems, the package information program that will be used (along with
$PKGCHK) to look for installed versions of the Sun PRO C++ compiler. The default is
pkginfo.

PLATFORM
The name of the platform used to create the Environment. If no platform is specified
when the Environment is created, scons autodetects the platform.

env = Environment(tools = [])
if env['PLATFORM'] == 'cygwin':
Tool('mingw')(env)
else:
Tool('msvc')(env)

POAUTOINIT
The $POAUTOINIT variable, if set to True (on non-zero numeric value), let the msginit
tool to automatically initialize missing PO files with msginit(1). This applies to
both, POInit and POUpdate builders (and others that use any of them).

POCREATE_ALIAS
Common alias for all PO files created with POInit builder (default: 'po-create'). See
msginit tool and POInit builder.

POSUFFIX
Suffix used for PO files (default: '.po') See msginit tool and POInit builder.

POTDOMAIN
The $POTDOMAIN defines default domain, used to generate POT filename as $POTDOMAIN.pot
when no POT file name is provided by the user. This applies to POTUpdate, POInit and
POUpdate builders (and builders, that use them, e.g. Translate). Normally (if
$POTDOMAIN is not defined), the builders use messages.pot as default POT file name.

POTSUFFIX
Suffix used for PO Template files (default: '.pot'). See xgettext tool and POTUpdate
builder.

POTUPDATE_ALIAS
Name of the common phony target for all PO Templates created with POUpdate (default:
'pot-update'). See xgettext tool and POTUpdate builder.

POUPDATE_ALIAS
Common alias for all PO files being defined with POUpdate builder (default:
'po-update'). See msgmerge tool and POUpdate builder.

PRINT_CMD_LINE_FUNC
A Python function used to print the command lines as they are executed (assuming
command printing is not disabled by the -q or -s options or their equivalents). The
function should take four arguments: s, the command being executed (a string), target,
the target being built (file node, list, or string name(s)), source, the source(s)
used (file node, list, or string name(s)), and env, the environment being used.

The function must do the printing itself. The default implementation, used if this
variable is not set or is None, is:

def print_cmd_line(s, target, source, env):
sys.stdout.write(s + "\n")

Here's an example of a more interesting function:

def print_cmd_line(s, target, source, env):
sys.stdout.write("Building %s -> %s...\n" %
(' and '.join([str(x) for x in source]),
' and '.join([str(x) for x in target])))
env=Environment(PRINT_CMD_LINE_FUNC=print_cmd_line)
env.Program('foo', 'foo.c')

This just prints "Building targetname from sourcename..." instead of the actual
commands. Such a function could also log the actual commands to a log file, for
example.

PROGEMITTER
Contains the emitter specification for the Program builder. The manpage section
"Builder Objects" contains general information on specifying emitters.

PROGPREFIX
The prefix used for executable file names.

PROGSUFFIX
The suffix used for executable file names.

PSCOM
The command line used to convert TeX DVI files into a PostScript file.

PSCOMSTR
The string displayed when a TeX DVI file is converted into a PostScript file. If this
is not set, then $PSCOM (the command line) is displayed.

PSPREFIX
The prefix used for PostScript file names.

PSSUFFIX
The prefix used for PostScript file names.

QT_AUTOSCAN
Turn off scanning for mocable files. Use the Moc Builder to explicitly specify files
to run moc on.

QT_BINPATH
The path where the qt binaries are installed. The default value is '$QTDIR/bin'.

QT_CPPPATH
The path where the qt header files are installed. The default value is
'$QTDIR/include'. Note: If you set this variable to None, the tool won't change the
$CPPPATH construction variable.

QT_DEBUG
Prints lots of debugging information while scanning for moc files.

QT_LIB
Default value is 'qt'. You may want to set this to 'qt-mt'. Note: If you set this
variable to None, the tool won't change the $LIBS variable.

QT_LIBPATH
The path where the qt libraries are installed. The default value is '$QTDIR/lib'.
Note: If you set this variable to None, the tool won't change the $LIBPATH
construction variable.

QT_MOC
Default value is '$QT_BINPATH/moc'.

QT_MOCCXXPREFIX
Default value is ''. Prefix for moc output files, when source is a cxx file.

QT_MOCCXXSUFFIX
Default value is '.moc'. Suffix for moc output files, when source is a cxx file.

QT_MOCFROMCXXCOM
Command to generate a moc file from a cpp file.

QT_MOCFROMCXXCOMSTR
The string displayed when generating a moc file from a cpp file. If this is not set,
then $QT_MOCFROMCXXCOM (the command line) is displayed.

QT_MOCFROMCXXFLAGS
Default value is '-i'. These flags are passed to moc, when moccing a C++ file.

QT_MOCFROMHCOM
Command to generate a moc file from a header.

QT_MOCFROMHCOMSTR
The string displayed when generating a moc file from a cpp file. If this is not set,
then $QT_MOCFROMHCOM (the command line) is displayed.

QT_MOCFROMHFLAGS
Default value is ''. These flags are passed to moc, when moccing a header file.

QT_MOCHPREFIX
Default value is 'moc_'. Prefix for moc output files, when source is a header.

QT_MOCHSUFFIX
Default value is '$CXXFILESUFFIX'. Suffix for moc output files, when source is a
header.

QT_UIC
Default value is '$QT_BINPATH/uic'.

QT_UICCOM
Command to generate header files from .ui files.

QT_UICCOMSTR
The string displayed when generating header files from .ui files. If this is not set,
then $QT_UICCOM (the command line) is displayed.

QT_UICDECLFLAGS
Default value is ''. These flags are passed to uic, when creating a a h file from a
.ui file.

QT_UICDECLPREFIX
Default value is ''. Prefix for uic generated header files.

QT_UICDECLSUFFIX
Default value is '.h'. Suffix for uic generated header files.

QT_UICIMPLFLAGS
Default value is ''. These flags are passed to uic, when creating a cxx file from a
.ui file.

QT_UICIMPLPREFIX
Default value is 'uic_'. Prefix for uic generated implementation files.

QT_UICIMPLSUFFIX
Default value is '$CXXFILESUFFIX'. Suffix for uic generated implementation files.

QT_UISUFFIX
Default value is '.ui'. Suffix of designer input files.

QTDIR
The qt tool tries to take this from os.environ. It also initializes all QT_*
construction variables listed below. (Note that all paths are constructed with
python's os.path.join() method, but are listed here with the '/' separator for easier
reading.) In addition, the construction environment variables $CPPPATH, $LIBPATH and
$LIBS may be modified and the variables $PROGEMITTER, $SHLIBEMITTER and $LIBEMITTER
are modified. Because the build-performance is affected when using this tool, you have
to explicitly specify it at Environment creation:

Environment(tools=['default','qt'])

The qt tool supports the following operations:

Automatic moc file generation from header files. You do not have to specify moc files
explicitly, the tool does it for you. However, there are a few preconditions to do so:
Your header file must have the same filebase as your implementation file and must stay
in the same directory. It must have one of the suffixes .h, .hpp, .H, .hxx, .hh. You
can turn off automatic moc file generation by setting QT_AUTOSCAN to 0. See also the
corresponding Moc() builder method.

Automatic moc file generation from cxx files. As stated in the qt documentation,
include the moc file at the end of the cxx file. Note that you have to include the
file, which is generated by the transformation
${QT_MOCCXXPREFIX}<basename>${QT_MOCCXXSUFFIX}, by default <basename>.moc. A warning
is generated after building the moc file, if you do not include the correct file. If
you are using VariantDir, you may need to specify duplicate=1. You can turn off
automatic moc file generation by setting QT_AUTOSCAN to 0. See also the corresponding
Moc builder method.

Automatic handling of .ui files. The implementation files generated from .ui files
are handled much the same as yacc or lex files. Each .ui file given as a source of
Program, Library or SharedLibrary will generate three files, the declaration file, the
implementation file and a moc file. Because there are also generated headers, you may
need to specify duplicate=1 in calls to VariantDir. See also the corresponding Uic
builder method.

RANLIB
The archive indexer.

RANLIBCOM
The command line used to index a static library archive.

RANLIBCOMSTR
The string displayed when a static library archive is indexed. If this is not set,
then $RANLIBCOM (the command line) is displayed.

env = Environment(RANLIBCOMSTR = "Indexing $TARGET")

RANLIBFLAGS
General options passed to the archive indexer.

RC
The resource compiler used to build a Microsoft Visual C++ resource file.

RCCOM
The command line used to build a Microsoft Visual C++ resource file.

RCCOMSTR
The string displayed when invoking the resource compiler to build a Microsoft Visual
C++ resource file. If this is not set, then $RCCOM (the command line) is displayed.

RCFLAGS
The flags passed to the resource compiler by the RES builder.

RCINCFLAGS
An automatically-generated construction variable containing the command-line options
for specifying directories to be searched by the resource compiler. The value of
$RCINCFLAGS is created by respectively prepending and appending $RCINCPREFIX and
$RCINCSUFFIX to the beginning and end of each directory in $CPPPATH.

RCINCPREFIX
The prefix (flag) used to specify an include directory on the resource compiler
command line. This will be prepended to the beginning of each directory in the
$CPPPATH construction variable when the $RCINCFLAGS variable is expanded.

RCINCSUFFIX
The suffix used to specify an include directory on the resource compiler command line.
This will be appended to the end of each directory in the $CPPPATH construction
variable when the $RCINCFLAGS variable is expanded.

RDirs
A function that converts a string into a list of Dir instances by searching the
repositories.

REGSVR
The program used on Windows systems to register a newly-built DLL library whenever the
SharedLibrary builder is passed a keyword argument of register=1.

REGSVRCOM
The command line used on Windows systems to register a newly-built DLL library
whenever the SharedLibrary builder is passed a keyword argument of register=1.

REGSVRCOMSTR
The string displayed when registering a newly-built DLL file. If this is not set, then
$REGSVRCOM (the command line) is displayed.

REGSVRFLAGS
Flags passed to the DLL registration program on Windows systems when a newly-built DLL
library is registered. By default, this includes the /s that prevents dialog boxes
from popping up and requiring user attention.

RMIC
The Java RMI stub compiler.

RMICCOM
The command line used to compile stub and skeleton class files from Java classes that
contain RMI implementations. Any options specified in the $RMICFLAGS construction
variable are included on this command line.

RMICCOMSTR
The string displayed when compiling stub and skeleton class files from Java classes
that contain RMI implementations. If this is not set, then $RMICCOM (the command line)
is displayed.

env = Environment(RMICCOMSTR = "Generating stub/skeleton class files $TARGETS from $SOURCES")

RMICFLAGS
General options passed to the Java RMI stub compiler.

RPATH
A list of paths to search for shared libraries when running programs. Currently only
used in the GNU (gnulink), IRIX (sgilink) and Sun (sunlink) linkers. Ignored on
platforms and toolchains that don't support it. Note that the paths added to RPATH are
not transformed by scons in any way: if you want an absolute path, you must make it
absolute yourself.

_RPATH
An automatically-generated construction variable containing the rpath flags to be used
when linking a program with shared libraries. The value of $_RPATH is created by
respectively prepending $RPATHPREFIX and appending $RPATHSUFFIX to the beginning and
end of each directory in $RPATH.

RPATHPREFIX
The prefix used to specify a directory to be searched for shared libraries when
running programs. This will be prepended to the beginning of each directory in the
$RPATH construction variable when the $_RPATH variable is automatically generated.

RPATHSUFFIX
The suffix used to specify a directory to be searched for shared libraries when
running programs. This will be appended to the end of each directory in the $RPATH
construction variable when the $_RPATH variable is automatically generated.

RPCGEN
The RPC protocol compiler.

RPCGENCLIENTFLAGS
Options passed to the RPC protocol compiler when generating client side stubs. These
are in addition to any flags specified in the $RPCGENFLAGS construction variable.

RPCGENFLAGS
General options passed to the RPC protocol compiler.

RPCGENHEADERFLAGS
Options passed to the RPC protocol compiler when generating a header file. These are
in addition to any flags specified in the $RPCGENFLAGS construction variable.

RPCGENSERVICEFLAGS
Options passed to the RPC protocol compiler when generating server side stubs. These
are in addition to any flags specified in the $RPCGENFLAGS construction variable.

RPCGENXDRFLAGS
Options passed to the RPC protocol compiler when generating XDR routines. These are in
addition to any flags specified in the $RPCGENFLAGS construction variable.

SCANNERS
A list of the available implicit dependency scanners. New file scanners may be added
by appending to this list, although the more flexible approach is to associate
scanners with a specific Builder. See the manpage sections "Builder Objects" and
"Scanner Objects" for more information.

SCONS_HOME
The (optional) path to the SCons library directory, initialized from the external
environment. If set, this is used to construct a shorter and more efficient search
path in the $MSVSSCONS command line executed from Microsoft Visual Studio project
files.

SHCC
The C compiler used for generating shared-library objects. See also $CC for compiling
to static objects.

SHCCCOM
The command line used to compile a C source file to a shared-library object file. Any
options specified in the $SHCFLAGS, $SHCCFLAGS and $CPPFLAGS construction variables
are included on this command line. See also $CCCOM for compiling to static objects.

SHCCCOMSTR
If set, the string displayed when a C source file is compiled to a shared object file.
If not set, then $SHCCCOM (the command line) is displayed. See also $CCCOMSTR for
compiling to static objects.

env = Environment(SHCCCOMSTR = "Compiling shared object $TARGET")

SHCCFLAGS
Options that are passed to the C and C++ compilers to generate shared-library objects.
See also $CCFLAGS for compiling to static objects.

SHCFLAGS
Options that are passed to the C compiler (only; not C++) to generate shared-library
objects. See also $CFLAGS for compiling to static objects.

SHCXX
The C++ compiler used for generating shared-library objects. See also $CXX for
compiling to static objects.

SHCXXCOM
The command line used to compile a C++ source file to a shared-library object file.
Any options specified in the $SHCXXFLAGS and $CPPFLAGS construction variables are
included on this command line. See also $CXXCOM for compiling to static objects.

SHCXXCOMSTR
If set, the string displayed when a C++ source file is compiled to a shared object
file. If not set, then $SHCXXCOM (the command line) is displayed. See also $CXXCOMSTR
for compiling to static objects.

env = Environment(SHCXXCOMSTR = "Compiling shared object $TARGET")

SHCXXFLAGS
Options that are passed to the C++ compiler to generate shared-library objects. See
also $CXXFLAGS for compiling to static objects.

SHDC
The name of the compiler to use when compiling D source destined to be in a shared
objects. See also $DC for compiling to static objects.

SHDCOM
The command line to use when compiling code to be part of shared objects. See also
$DCOM for compiling to static objects.

SHDCOMSTR
If set, the string displayed when a D source file is compiled to a (shared) object
file. If not set, then $SHDCOM (the command line) is displayed. See also $DCOMSTR for
compiling to static objects.

SHDLIBVERSION
SHDLIBVERSION.

SHDLIBVERSIONFLAGS
SHDLIBVERSIONFLAGS.

SHDLINK
The linker to use when creating shared objects for code bases include D sources. See
also $DLINK for linking static objects.

SHDLINKCOM
The command line to use when generating shared objects. See also $DLINKCOM for linking
static objects.

SHDLINKFLAGS
The list of flags to use when generating a shared object. See also $DLINKFLAGS for
linking static objects.

SHELL
A string naming the shell program that will be passed to the $SPAWN function. See the
$SPAWN construction variable for more information.

SHF03
The Fortran 03 compiler used for generating shared-library objects. You should
normally set the $SHFORTRAN variable, which specifies the default Fortran compiler for
all Fortran versions. You only need to set $SHF03 if you need to use a specific
compiler or compiler version for Fortran 03 files.

SHF03COM
The command line used to compile a Fortran 03 source file to a shared-library object
file. You only need to set $SHF03COM if you need to use a specific command line for
Fortran 03 files. You should normally set the $SHFORTRANCOM variable, which specifies
the default command line for all Fortran versions.

SHF03COMSTR
If set, the string displayed when a Fortran 03 source file is compiled to a
shared-library object file. If not set, then $SHF03COM or $SHFORTRANCOM (the command
line) is displayed.

SHF03FLAGS
Options that are passed to the Fortran 03 compiler to generated shared-library
objects. You only need to set $SHF03FLAGS if you need to define specific user options
for Fortran 03 files. You should normally set the $SHFORTRANFLAGS variable, which
specifies the user-specified options passed to the default Fortran compiler for all
Fortran versions.

SHF03PPCOM
The command line used to compile a Fortran 03 source file to a shared-library object
file after first running the file through the C preprocessor. Any options specified in
the $SHF03FLAGS and $CPPFLAGS construction variables are included on this command
line. You only need to set $SHF03PPCOM if you need to use a specific C-preprocessor
command line for Fortran 03 files. You should normally set the $SHFORTRANPPCOM
variable, which specifies the default C-preprocessor command line for all Fortran
versions.

SHF03PPCOMSTR
If set, the string displayed when a Fortran 03 source file is compiled to a
shared-library object file after first running the file through the C preprocessor. If
not set, then $SHF03PPCOM or $SHFORTRANPPCOM (the command line) is displayed.

SHF08
The Fortran 08 compiler used for generating shared-library objects. You should
normally set the $SHFORTRAN variable, which specifies the default Fortran compiler for
all Fortran versions. You only need to set $SHF08 if you need to use a specific
compiler or compiler version for Fortran 08 files.

SHF08COM
The command line used to compile a Fortran 08 source file to a shared-library object
file. You only need to set $SHF08COM if you need to use a specific command line for
Fortran 08 files. You should normally set the $SHFORTRANCOM variable, which specifies
the default command line for all Fortran versions.

SHF08COMSTR
If set, the string displayed when a Fortran 08 source file is compiled to a
shared-library object file. If not set, then $SHF08COM or $SHFORTRANCOM (the command
line) is displayed.

SHF08FLAGS
Options that are passed to the Fortran 08 compiler to generated shared-library
objects. You only need to set $SHF08FLAGS if you need to define specific user options
for Fortran 08 files. You should normally set the $SHFORTRANFLAGS variable, which
specifies the user-specified options passed to the default Fortran compiler for all
Fortran versions.

SHF08PPCOM
The command line used to compile a Fortran 08 source file to a shared-library object
file after first running the file through the C preprocessor. Any options specified in
the $SHF08FLAGS and $CPPFLAGS construction variables are included on this command
line. You only need to set $SHF08PPCOM if you need to use a specific C-preprocessor
command line for Fortran 08 files. You should normally set the $SHFORTRANPPCOM
variable, which specifies the default C-preprocessor command line for all Fortran
versions.

SHF08PPCOMSTR
If set, the string displayed when a Fortran 08 source file is compiled to a
shared-library object file after first running the file through the C preprocessor. If
not set, then $SHF08PPCOM or $SHFORTRANPPCOM (the command line) is displayed.

SHF77
The Fortran 77 compiler used for generating shared-library objects. You should
normally set the $SHFORTRAN variable, which specifies the default Fortran compiler for
all Fortran versions. You only need to set $SHF77 if you need to use a specific
compiler or compiler version for Fortran 77 files.

SHF77COM
The command line used to compile a Fortran 77 source file to a shared-library object
file. You only need to set $SHF77COM if you need to use a specific command line for
Fortran 77 files. You should normally set the $SHFORTRANCOM variable, which specifies
the default command line for all Fortran versions.

SHF77COMSTR
If set, the string displayed when a Fortran 77 source file is compiled to a
shared-library object file. If not set, then $SHF77COM or $SHFORTRANCOM (the command
line) is displayed.

SHF77FLAGS
Options that are passed to the Fortran 77 compiler to generated shared-library
objects. You only need to set $SHF77FLAGS if you need to define specific user options
for Fortran 77 files. You should normally set the $SHFORTRANFLAGS variable, which
specifies the user-specified options passed to the default Fortran compiler for all
Fortran versions.

SHF77PPCOM
The command line used to compile a Fortran 77 source file to a shared-library object
file after first running the file through the C preprocessor. Any options specified in
the $SHF77FLAGS and $CPPFLAGS construction variables are included on this command
line. You only need to set $SHF77PPCOM if you need to use a specific C-preprocessor
command line for Fortran 77 files. You should normally set the $SHFORTRANPPCOM
variable, which specifies the default C-preprocessor command line for all Fortran
versions.

SHF77PPCOMSTR
If set, the string displayed when a Fortran 77 source file is compiled to a
shared-library object file after first running the file through the C preprocessor. If
not set, then $SHF77PPCOM or $SHFORTRANPPCOM (the command line) is displayed.

SHF90
The Fortran 90 compiler used for generating shared-library objects. You should
normally set the $SHFORTRAN variable, which specifies the default Fortran compiler for
all Fortran versions. You only need to set $SHF90 if you need to use a specific
compiler or compiler version for Fortran 90 files.

SHF90COM
The command line used to compile a Fortran 90 source file to a shared-library object
file. You only need to set $SHF90COM if you need to use a specific command line for
Fortran 90 files. You should normally set the $SHFORTRANCOM variable, which specifies
the default command line for all Fortran versions.

SHF90COMSTR
If set, the string displayed when a Fortran 90 source file is compiled to a
shared-library object file. If not set, then $SHF90COM or $SHFORTRANCOM (the command
line) is displayed.

SHF90FLAGS
Options that are passed to the Fortran 90 compiler to generated shared-library
objects. You only need to set $SHF90FLAGS if you need to define specific user options
for Fortran 90 files. You should normally set the $SHFORTRANFLAGS variable, which
specifies the user-specified options passed to the default Fortran compiler for all
Fortran versions.

SHF90PPCOM
The command line used to compile a Fortran 90 source file to a shared-library object
file after first running the file through the C preprocessor. Any options specified in
the $SHF90FLAGS and $CPPFLAGS construction variables are included on this command
line. You only need to set $SHF90PPCOM if you need to use a specific C-preprocessor
command line for Fortran 90 files. You should normally set the $SHFORTRANPPCOM
variable, which specifies the default C-preprocessor command line for all Fortran
versions.

SHF90PPCOMSTR
If set, the string displayed when a Fortran 90 source file is compiled to a
shared-library object file after first running the file through the C preprocessor. If
not set, then $SHF90PPCOM or $SHFORTRANPPCOM (the command line) is displayed.

SHF95
The Fortran 95 compiler used for generating shared-library objects. You should
normally set the $SHFORTRAN variable, which specifies the default Fortran compiler for
all Fortran versions. You only need to set $SHF95 if you need to use a specific
compiler or compiler version for Fortran 95 files.

SHF95COM
The command line used to compile a Fortran 95 source file to a shared-library object
file. You only need to set $SHF95COM if you need to use a specific command line for
Fortran 95 files. You should normally set the $SHFORTRANCOM variable, which specifies
the default command line for all Fortran versions.

SHF95COMSTR
If set, the string displayed when a Fortran 95 source file is compiled to a
shared-library object file. If not set, then $SHF95COM or $SHFORTRANCOM (the command
line) is displayed.

SHF95FLAGS
Options that are passed to the Fortran 95 compiler to generated shared-library
objects. You only need to set $SHF95FLAGS if you need to define specific user options
for Fortran 95 files. You should normally set the $SHFORTRANFLAGS variable, which
specifies the user-specified options passed to the default Fortran compiler for all
Fortran versions.

SHF95PPCOM
The command line used to compile a Fortran 95 source file to a shared-library object
file after first running the file through the C preprocessor. Any options specified in
the $SHF95FLAGS and $CPPFLAGS construction variables are included on this command
line. You only need to set $SHF95PPCOM if you need to use a specific C-preprocessor
command line for Fortran 95 files. You should normally set the $SHFORTRANPPCOM
variable, which specifies the default C-preprocessor command line for all Fortran
versions.

SHF95PPCOMSTR
If set, the string displayed when a Fortran 95 source file is compiled to a
shared-library object file after first running the file through the C preprocessor. If
not set, then $SHF95PPCOM or $SHFORTRANPPCOM (the command line) is displayed.

SHFORTRAN
The default Fortran compiler used for generating shared-library objects.

SHFORTRANCOM
The command line used to compile a Fortran source file to a shared-library object
file.

SHFORTRANCOMSTR
If set, the string displayed when a Fortran source file is compiled to a
shared-library object file. If not set, then $SHFORTRANCOM (the command line) is
displayed.

SHFORTRANFLAGS
Options that are passed to the Fortran compiler to generate shared-library objects.

SHFORTRANPPCOM
The command line used to compile a Fortran source file to a shared-library object file
after first running the file through the C preprocessor. Any options specified in the
$SHFORTRANFLAGS and $CPPFLAGS construction variables are included on this command
line.

SHFORTRANPPCOMSTR
If set, the string displayed when a Fortran source file is compiled to a
shared-library object file after first running the file through the C preprocessor. If
not set, then $SHFORTRANPPCOM (the command line) is displayed.

SHLIBEMITTER
Contains the emitter specification for the SharedLibrary builder. The manpage section
"Builder Objects" contains general information on specifying emitters.

SHLIBNOVERSIONSYMLINKS
Instructs the SharedLibrary builder to not create symlinks for versioned shared
libraries.

SHLIBPREFIX
The prefix used for shared library file names.

_SHLIBSONAME
A macro that automatically generates shared library's SONAME based on $TARGET,
$SHLIBVERSION and $SHLIBSUFFIX. Used by SharedLibrary builder when the linker tool
supports SONAME (e.g. gnulink).

SHLIBSUFFIX
The suffix used for shared library file names.

SHLIBVERSION
When this construction variable is defined, a versioned shared library is created by
the SharedLibrary builder. This activates the $_SHLIBVERSIONFLAGS and thus modifies
the $SHLINKCOM as required, adds the version number to the library name, and creates
the symlinks that are needed. $SHLIBVERSION versions should exist as alpha-numeric,
decimal-delimited values as defined by the regular expression "\w+[\.\w+]*". Example
$SHLIBVERSION values include '1', '1.2.3', and '1.2.gitaa412c8b'.

_SHLIBVERSIONFLAGS
This macro automatically introduces extra flags to $SHLINKCOM when building versioned
SharedLibrary (that is when $SHLIBVERSION is set). _SHLIBVERSIONFLAGS usually adds
$SHLIBVERSIONFLAGS and some extra dynamically generated options (such as
-Wl,-soname=$_SHLIBSONAME. It is unused by "plain" (unversioned) shared libraries.

SHLIBVERSIONFLAGS
Extra flags added to $SHLINKCOM when building versioned SharedLibrary. These flags are
only used when $SHLIBVERSION is set.

SHLINK
The linker for programs that use shared libraries. See also $LINK for linking static
objects.

SHLINKCOM
The command line used to link programs using shared libraries. See also $LINKCOM for
linking static objects.

SHLINKCOMSTR
The string displayed when programs using shared libraries are linked. If this is not
set, then $SHLINKCOM (the command line) is displayed. See also $LINKCOMSTR for linking
static objects.

env = Environment(SHLINKCOMSTR = "Linking shared $TARGET")

SHLINKFLAGS
General user options passed to the linker for programs using shared libraries. Note
that this variable should not contain -l (or similar) options for linking with the
libraries listed in $LIBS, nor -L (or similar) include search path options that scons
generates automatically from $LIBPATH. See $_LIBFLAGS above, for the variable that
expands to library-link options, and $_LIBDIRFLAGS above, for the variable that
expands to library search path options. See also $LINKFLAGS for linking static
objects.

SHOBJPREFIX
The prefix used for shared object file names.

SHOBJSUFFIX
The suffix used for shared object file names.

SONAME
Variable used to hard-code SONAME for versioned shared library/loadable module.

env.SharedLibrary('test', 'test.c', SHLIBVERSION='0.1.2', SONAME='libtest.so.2')

The variable is used, for example, by gnulink linker tool.

SOURCE
A reserved variable name that may not be set or used in a construction environment.
(See the manpage section "Variable Substitution" for more information).

SOURCE_URL
The URL (web address) of the location from which the project was retrieved. This is
used to fill in the Source: field in the controlling information for Ipkg and RPM
packages.

SOURCES
A reserved variable name that may not be set or used in a construction environment.
(See the manpage section "Variable Substitution" for more information).

SPAWN
A command interpreter function that will be called to execute command line strings.
The function must expect the following arguments:

def spawn(shell, escape, cmd, args, env):

sh is a string naming the shell program to use. escape is a function that can be
called to escape shell special characters in the command line. cmd is the path to the
command to be executed. args is the arguments to the command. env is a dictionary of
the environment variables in which the command should be executed.

STATIC_AND_SHARED_OBJECTS_ARE_THE_SAME
When this variable is true, static objects and shared objects are assumed to be the
same; that is, SCons does not check for linking static objects into a shared library.

SUBST_DICT
The dictionary used by the Substfile or Textfile builders for substitution values. It
can be anything acceptable to the dict() constructor, so in addition to a dictionary,
lists of tuples are also acceptable.

SUBSTFILEPREFIX
The prefix used for Substfile file names, an empty string by default.

SUBSTFILESUFFIX
The suffix used for Substfile file names, an empty string by default.

SUMMARY
A short summary of what the project is about. This is used to fill in the Summary:
field in the controlling information for Ipkg and RPM packages, and as the
Description: field in MSI packages.

SWIG
The scripting language wrapper and interface generator.

SWIGCFILESUFFIX
The suffix that will be used for intermediate C source files generated by the
scripting language wrapper and interface generator. The default value is
_wrap$CFILESUFFIX. By default, this value is used whenever the -c++ option is not
specified as part of the $SWIGFLAGS construction variable.

SWIGCOM
The command line used to call the scripting language wrapper and interface generator.

SWIGCOMSTR
The string displayed when calling the scripting language wrapper and interface
generator. If this is not set, then $SWIGCOM (the command line) is displayed.

SWIGCXXFILESUFFIX
The suffix that will be used for intermediate C++ source files generated by the
scripting language wrapper and interface generator. The default value is
_wrap$CFILESUFFIX. By default, this value is used whenever the -c++ option is
specified as part of the $SWIGFLAGS construction variable.

SWIGDIRECTORSUFFIX
The suffix that will be used for intermediate C++ header files generated by the
scripting language wrapper and interface generator. These are only generated for C++
code when the SWIG 'directors' feature is turned on. The default value is _wrap.h.

SWIGFLAGS
General options passed to the scripting language wrapper and interface generator. This
is where you should set -python, -perl5, -tcl, or whatever other options you want to
specify to SWIG. If you set the -c++ option in this variable, scons will, by default,
generate a C++ intermediate source file with the extension that is specified as the
$CXXFILESUFFIX variable.

_SWIGINCFLAGS
An automatically-generated construction variable containing the SWIG command-line
options for specifying directories to be searched for included files. The value of
$_SWIGINCFLAGS is created by respectively prepending and appending $SWIGINCPREFIX and
$SWIGINCSUFFIX to the beginning and end of each directory in $SWIGPATH.

SWIGINCPREFIX
The prefix used to specify an include directory on the SWIG command line. This will be
prepended to the beginning of each directory in the $SWIGPATH construction variable
when the $_SWIGINCFLAGS variable is automatically generated.

SWIGINCSUFFIX
The suffix used to specify an include directory on the SWIG command line. This will be
appended to the end of each directory in the $SWIGPATH construction variable when the
$_SWIGINCFLAGS variable is automatically generated.

SWIGOUTDIR
Specifies the output directory in which the scripting language wrapper and interface
generator should place generated language-specific files. This will be used by SCons
to identify the files that will be generated by the swig call, and translated into the
swig -outdir option on the command line.

SWIGPATH
The list of directories that the scripting language wrapper and interface generate
will search for included files. The SWIG implicit dependency scanner will search these
directories for include files. The default value is an empty list.

Don't explicitly put include directory arguments in SWIGFLAGS; the result will be
non-portable and the directories will not be searched by the dependency scanner. Note:
directory names in SWIGPATH will be looked-up relative to the SConscript directory
when they are used in a command. To force scons to look-up a directory relative to the
root of the source tree use #:

env = Environment(SWIGPATH='#/include')

The directory look-up can also be forced using the Dir() function:

include = Dir('include')
env = Environment(SWIGPATH=include)

The directory list will be added to command lines through the automatically-generated
$_SWIGINCFLAGS construction variable, which is constructed by respectively prepending
and appending the values of the $SWIGINCPREFIX and $SWIGINCSUFFIX construction
variables to the beginning and end of each directory in $SWIGPATH. Any command lines
you define that need the SWIGPATH directory list should include $_SWIGINCFLAGS:

env = Environment(SWIGCOM="my_swig -o $TARGET $_SWIGINCFLAGS $SOURCES")

SWIGVERSION
The version number of the SWIG tool.

TAR
The tar archiver.

TARCOM
The command line used to call the tar archiver.

TARCOMSTR
The string displayed when archiving files using the tar archiver. If this is not set,
then $TARCOM (the command line) is displayed.

env = Environment(TARCOMSTR = "Archiving $TARGET")

TARFLAGS
General options passed to the tar archiver.

TARGET
A reserved variable name that may not be set or used in a construction environment.
(See the manpage section "Variable Substitution" for more information).

TARGET_ARCH
The name of the target hardware architecture for the compiled objects created by this
Environment. This defaults to the value of HOST_ARCH, and the user can override it.
Currently only set for Win32.

Sets the target architecture for Visual Studio compiler (i.e. the arch of the binaries
generated by the compiler). If not set, default to $HOST_ARCH, or, if that is unset,
to the architecture of the running machine's OS (note that the python build or
architecture has no effect). This variable must be passed as an argument to the
Environment() constructor; setting it later has no effect. This is currently only used
on Windows, but in the future it will be used on other OSes as well. If this is set
and $MSVC_VERSION is not set, this will search for all installed MSVC's that support
the $TARGET_ARCH, selecting the latest version for use.

On Windows, valid target values are x86, arm, i386 for 32-bit targets and amd64,
arm64, em64t, x86_64 and ia64 (Itanium) for 64-bit targets. Note that not all target
architectures are supported for all Visual Studio / MSVC versions check the relevant
Microsoft documentation.

For example, if you want to compile 64-bit binaries, you would set
TARGET_ARCH='x86_64' in your SCons environment.

TARGET_OS
The name of the target operating system for the compiled objects created by this
Environment. This defaults to the value of HOST_OS, and the user can override it.
Currently only set for Win32.

TARGETS
A reserved variable name that may not be set or used in a construction environment.
(See the manpage section "Variable Substitution" for more information).

TARSUFFIX
The suffix used for tar file names.

TEMPFILEARGJOIN
The string (or character) to be used to join the arguments passed to TEMPFILE when
command line exceeds the limit set by $MAXLINELENGTH. The default value is a space.
However for MSVC, MSLINK the default is a line seperator characters as defined by
os.linesep. Note this value is used literally and not expanded by the subst logic.

TEMPFILEDIR
The directory to create the tempfile in.

TEMPFILEPREFIX
The prefix for a temporary file used to store lines lines longer than $MAXLINELENGTH
as operations which call out to a shell will fail if the line is too long, which
particularly impacts linking. The default is '@', which works for the Microsoft and
GNU toolchains on Windows. Set this appropriately for other toolchains, for example
'-@' for the diab compiler or '-via' for ARM toolchain.

TEMPFILESUFFIX
The suffix used for the temporary file name used for long command lines. The name
should include the dot ('.') if one is wanted as it will not be added automatically.
The default is '.lnk'.

TEX
The TeX formatter and typesetter.

TEXCOM
The command line used to call the TeX formatter and typesetter.

TEXCOMSTR
The string displayed when calling the TeX formatter and typesetter. If this is not
set, then $TEXCOM (the command line) is displayed.

env = Environment(TEXCOMSTR = "Building $TARGET from TeX input $SOURCES")

TEXFLAGS
General options passed to the TeX formatter and typesetter.

TEXINPUTS
List of directories that the LaTeX program will search for include directories. The
LaTeX implicit dependency scanner will search these directories for \include and
\import files.

TEXTFILEPREFIX
The prefix used for Textfile file names, an empty string by default.

TEXTFILESUFFIX
The suffix used for Textfile file names; .txt by default.

TOOLS
A list of the names of the Tool specifications that are part of this construction
environment.

UNCHANGED_SOURCES
A reserved variable name that may not be set or used in a construction environment.
(See the manpage section "Variable Substitution" for more information).

UNCHANGED_TARGETS
A reserved variable name that may not be set or used in a construction environment.
(See the manpage section "Variable Substitution" for more information).

VENDOR
The person or organization who supply the packaged software. This is used to fill in
the Vendor: field in the controlling information for RPM packages, and the
Manufacturer: field in the controlling information for MSI packages.

VERSION
The version of the project, specified as a string.

VSWHERE
Specify the location of vswhere.exe.

The vswhere.exe executable is distributed with Microsoft Visual Studio and Build Tools
since the 2017 edition, but is also available standalone. It provides full information
about installations of 2017 and later editions. With the -legacy argument, vswhere.exe
can detect installations of the 2010 through 2015 editions with limited data returned.
If VSWHERE is set, SCons will use that location.

Otherwise SCons will look in the following locations and set VSWHERE to the path of
the first vswhere.exe located.

• %ProgramFiles(x86)%\Microsoft Visual Studio\Installer

• %ProgramFiles%\Microsoft Visual Studio\Installer

• %ChocolateyInstall%\bin

Note that VSWHERE must be set at the same time or prior to any of msvc, msvs , and/or
mslink Tool being initialized. Either set it as follows

env = Environment(VSWHERE='c:/my/path/to/vswhere')

or if your construction environment is created specifying an empty tools list (or a
list of tools which omits all of default, msvs, msvc, and mslink), and also before
env.Tool is called to ininitialize any of those tools:

env = Environment(tools=[])
env['VSWHERE'] = r'c:/my/vswhere/install/location/vswhere.exe'
env.Tool('msvc')
env.Tool('mslink')
env.Tool('msvs')

WIN32_INSERT_DEF
A deprecated synonym for $WINDOWS_INSERT_DEF.

WIN32DEFPREFIX
A deprecated synonym for $WINDOWSDEFPREFIX.

WIN32DEFSUFFIX
A deprecated synonym for $WINDOWSDEFSUFFIX.

WIN32EXPPREFIX
A deprecated synonym for $WINDOWSEXPSUFFIX.

WIN32EXPSUFFIX
A deprecated synonym for $WINDOWSEXPSUFFIX.

WINDOWS_EMBED_MANIFEST
Set this variable to True or 1 to embed the compiler-generated manifest (normally
${TARGET}.manifest) into all Windows exes and DLLs built with this environment, as a
resource during their link step. This is done using $MT and $MTEXECOM and $MTSHLIBCOM.

WINDOWS_INSERT_DEF
When this is set to true, a library build of a Windows shared library (.dll file) will
also build a corresponding .def file at the same time, if a .def file is not already
listed as a build target. The default is 0 (do not build a .def file).

WINDOWS_INSERT_MANIFEST
When this is set to true, scons will be aware of the .manifest files generated by
Microsoft Visua C/C++ 8.

WINDOWSDEFPREFIX
The prefix used for Windows .def file names.

WINDOWSDEFSUFFIX
The suffix used for Windows .def file names.

WINDOWSEXPPREFIX
The prefix used for Windows .exp file names.

WINDOWSEXPSUFFIX
The suffix used for Windows .exp file names.

WINDOWSPROGMANIFESTPREFIX
The prefix used for executable program .manifest files generated by Microsoft Visual
C/C++.

WINDOWSPROGMANIFESTSUFFIX
The suffix used for executable program .manifest files generated by Microsoft Visual
C/C++.

WINDOWSSHLIBMANIFESTPREFIX
The prefix used for shared library .manifest files generated by Microsoft Visual
C/C++.

WINDOWSSHLIBMANIFESTSUFFIX
The suffix used for shared library .manifest files generated by Microsoft Visual
C/C++.

X_IPK_DEPENDS
This is used to fill in the Depends: field in the controlling information for Ipkg
packages.

X_IPK_DESCRIPTION
This is used to fill in the Description: field in the controlling information for Ipkg
packages. The default value is $SUMMARY\n$DESCRIPTION

X_IPK_MAINTAINER
This is used to fill in the Maintainer: field in the controlling information for Ipkg
packages.

X_IPK_PRIORITY
This is used to fill in the Priority: field in the controlling information for Ipkg
packages.

X_IPK_SECTION
This is used to fill in the Section: field in the controlling information for Ipkg
packages.

X_MSI_LANGUAGE
This is used to fill in the Language: attribute in the controlling information for MSI
packages.

X_MSI_LICENSE_TEXT
The text of the software license in RTF format. Carriage return characters will be
replaced with the RTF equivalent \\par.

X_MSI_UPGRADE_CODE
TODO

X_RPM_AUTOREQPROV
This is used to fill in the AutoReqProv: field in the RPM .spec file.

X_RPM_BUILD
internal, but overridable

X_RPM_BUILDREQUIRES
This is used to fill in the BuildRequires: field in the RPM .spec file. Note this
should only be used on a host managed by rpm as the dependencies will not be
resolvable at build time otherwise.

X_RPM_BUILDROOT
internal, but overridable

X_RPM_CLEAN
internal, but overridable

X_RPM_CONFLICTS
This is used to fill in the Conflicts: field in the RPM .spec file.

X_RPM_DEFATTR
This value is used as the default attributes for the files in the RPM package. The
default value is (-,root,root).

X_RPM_DISTRIBUTION
This is used to fill in the Distribution: field in the RPM .spec file.

X_RPM_EPOCH
This is used to fill in the Epoch: field in the RPM .spec file.

X_RPM_EXCLUDEARCH
This is used to fill in the ExcludeArch: field in the RPM .spec file.

X_RPM_EXLUSIVEARCH
This is used to fill in the ExclusiveArch: field in the RPM .spec file.

X_RPM_EXTRADEFS
A list used to supply extra defintions or flags to be added to the RPM .spec file.
Each item is added as-is with a carriage return appended. This is useful if some
specific RPM feature not otherwise anticipated by SCons needs to be turned on or off.
Note if this variable is omitted, SCons will by default supply the value '%global
debug_package %{nil}' to disable debug package generation. To enable debug package
generation, include this variable set either to None, or to a custom list that does
not include the default line. Added in version 3.1.

env.Package(
NAME="foo",
...
X_RPM_EXTRADEFS=[
"%define _unpackaged_files_terminate_build 0"
"%define _missing_doc_files_terminate_build 0"
],
...
)

X_RPM_GROUP
This is used to fill in the Group: field in the RPM .spec file.

X_RPM_GROUP_lang
This is used to fill in the Group(lang): field in the RPM .spec file. Note that lang
is not literal and should be replaced by the appropriate language code.

X_RPM_ICON
This is used to fill in the Icon: field in the RPM .spec file.

X_RPM_INSTALL
internal, but overridable

X_RPM_PACKAGER
This is used to fill in the Packager: field in the RPM .spec file.

X_RPM_POSTINSTALL
This is used to fill in the %post: section in the RPM .spec file.

X_RPM_POSTUNINSTALL
This is used to fill in the %postun: section in the RPM .spec file.

X_RPM_PREFIX
This is used to fill in the Prefix: field in the RPM .spec file.

X_RPM_PREINSTALL
This is used to fill in the %pre: section in the RPM .spec file.

X_RPM_PREP
internal, but overridable

X_RPM_PREUNINSTALL
This is used to fill in the %preun: section in the RPM .spec file.

X_RPM_PROVIDES
This is used to fill in the Provides: field in the RPM .spec file.

X_RPM_REQUIRES
This is used to fill in the Requires: field in the RPM .spec file.

X_RPM_SERIAL
This is used to fill in the Serial: field in the RPM .spec file.

X_RPM_URL
This is used to fill in the Url: field in the RPM .spec file.

XGETTEXT
Path to xgettext(1) program (found via Detect()). See xgettext tool and POTUpdate
builder.

XGETTEXTCOM
Complete xgettext command line. See xgettext tool and POTUpdate builder.

XGETTEXTCOMSTR
A string that is shown when xgettext(1) command is invoked (default: '', which means
"print $XGETTEXTCOM"). See xgettext tool and POTUpdate builder.

_XGETTEXTDOMAIN
Internal "macro". Generates xgettext domain name form source and target (default:
'${TARGET.filebase}').

XGETTEXTFLAGS
Additional flags to xgettext(1). See xgettext tool and POTUpdate builder.

XGETTEXTFROM
Name of file containing list of xgettext(1)'s source files. Autotools' users know this
as POTFILES.in so they will in most cases set XGETTEXTFROM="POTFILES.in" here. The
$XGETTEXTFROM files have same syntax and semantics as the well known GNU POTFILES.in.
See xgettext tool and POTUpdate builder.

_XGETTEXTFROMFLAGS
Internal "macro". Genrates list of -D<dir> flags from the $XGETTEXTPATH list.

XGETTEXTFROMPREFIX
This flag is used to add single $XGETTEXTFROM file to xgettext(1)'s commandline
(default: '-f').

XGETTEXTFROMSUFFIX
(default: '')

XGETTEXTPATH
List of directories, there xgettext(1) will look for source files (default: []).

Note
This variable works only together with $XGETTEXTFROM
See also xgettext tool and POTUpdate builder.

_XGETTEXTPATHFLAGS
Internal "macro". Generates list of -f<file> flags from $XGETTEXTFROM.

XGETTEXTPATHPREFIX
This flag is used to add single search path to xgettext(1)'s commandline (default:
'-D').

XGETTEXTPATHSUFFIX
(default: '')

YACC
The parser generator.

YACCCOM
The command line used to call the parser generator to generate a source file.

YACCCOMSTR
The string displayed when generating a source file using the parser generator. If this
is not set, then $YACCCOM (the command line) is displayed.

env = Environment(YACCCOMSTR = "Yacc'ing $TARGET from $SOURCES")

YACCFLAGS
General options passed to the parser generator. If $YACCFLAGS contains a -d option,
SCons assumes that the call will also create a .h file (if the yacc source file ends
in a .y suffix) or a .hpp file (if the yacc source file ends in a .yy suffix)

YACCHFILESUFFIX
The suffix of the C header file generated by the parser generator when the -d option
is used. Note that setting this variable does not cause the parser generator to
generate a header file with the specified suffix, it exists to allow you to specify
what suffix the parser generator will use of its own accord. The default value is .h.

YACCHXXFILESUFFIX
The suffix of the C++ header file generated by the parser generator when the -d option
is used. Note that setting this variable does not cause the parser generator to
generate a header file with the specified suffix, it exists to allow you to specify
what suffix the parser generator will use of its own accord. The default value is
.hpp, except on Mac OS X, where the default is ${TARGET.suffix}.h. because the default
bison parser generator just appends .h to the name of the generated C++ file.

YACCVCGFILESUFFIX
The suffix of the file containing the VCG grammar automaton definition when the
--graph= option is used. Note that setting this variable does not cause the parser
generator to generate a VCG file with the specified suffix, it exists to allow you to
specify what suffix the parser generator will use of its own accord. The default value
is .vcg.

ZIP
The zip compression and file packaging utility.

ZIPCOM
The command line used to call the zip utility, or the internal Python function used to
create a zip archive.

ZIPCOMPRESSION
The compression flag from the Python zipfile module used by the internal Python
function to control whether the zip archive is compressed or not. The default value is
zipfile.ZIP_DEFLATED, which creates a compressed zip archive. This value has no effect
if the zipfile module is unavailable.

ZIPCOMSTR
The string displayed when archiving files using the zip utility. If this is not set,
then $ZIPCOM (the command line or internal Python function) is displayed.

env = Environment(ZIPCOMSTR = "Zipping $TARGET")

ZIPFLAGS
General options passed to the zip utility.

ZIPROOT
An optional zip root directory (default empty). The filenames stored in the zip file
will be relative to this directory, if given. Otherwise the filenames are relative to
the current directory of the command. For instance:

env = Environment()
env.Zip('foo.zip', 'subdir1/subdir2/file1', ZIPROOT='subdir1')

will produce a zip file foo.zip containing a file with the name subdir2/file1 rather
than subdir1/subdir2/file1.

ZIPSUFFIX
The suffix used for zip file names.

Configure Contexts
SCons supports a configure context, an integrated mechanism similar to the various
AC_CHECK macros in GNU Autoconf for testing the existence of external items needed for the
build, such as C header files, libraries, etc. The mechanism is portable across platforms.

scons does not maintain an explicit cache of the tested values (this is different than
Autoconf), but uses its normal dependency tracking to keep the checked values up to date.
However, users may override this behaviour with the --config command line option.

Configure(env, [custom_tests, conf_dir, log_file, config_h, clean, help]),
env.Configure([custom_tests, conf_dir, log_file, config_h, clean, help])
Create a configure context, which tracks information discovered while running tests.
The context includes a local construction environment (available as context.env) which
is used when running the tests and which can be updated with the check results. Only
one context may be active at a time (since 4.0, scons will raise an exception on an
attempt to create a new context when there is an active context), but a new context
can be created after the active one is completed. For the global function form, the
required env describes the initial values for the context's local construction
environment; for the construction environment method form the instance provides the
values.

custom_tests specifies a dictionary containing custom tests (see the section on custom
tests below). The default value is None, meaning no custom tests are added to the
configure context.

conf_dir specifies a directory where the test cases are built. This directory is not
used for building normal targets. The default value is “#/.sconf_temp”.

log_file specifies a file which collects the output from commands that are executed to
check for the existence of header files, libraries, etc. The default is
“#/config.log”. If you are using the VariantDir function, you may want to specify a
subdirectory under your variant directory.

config_h specifies a C header file where the results of tests will be written. The
results will consist of lines like #define HAVE_STDIO_H, #define HAVE_LIBM, etc.
Customarily, the name chosen is “config.h”. The default is to not write a config_h
file. You can specify the same config_h file in multiple calls to Configure, in which
case SCons will concatenate all results in the specified file. Note that SCons uses
its normal dependency checking to decide if it's necessary to rebuild the specified
config_h file. This means that the file is not necessarily re-built each time scons is
run, but is only rebuilt if its contents will have changed and some target that
depends on the config_h file is being built.

The clean and help arguments can be used to suppress execution of the configuration
tests when the -c/--clean or -H/-h/--help options are used, respectively. The default
behavior is always to execute configure context tests, since the results of the tests
may affect the list of targets to be cleaned or the help text. If the configure tests
do not affect these, then you may add the clean=False or help=False arguments (or
both) to avoid unnecessary test execution.

SConf.Finish(context), context.Finish()
This method must be called after configuration is done. Though required, this is not
enforced except if Configure is called again while there is still an active context,
in which case an exception is raised. Finish returns the environment as modified
during the course of running the configuration checks. After this method is called, no
further checks can be performed with this configuration context. However, you can
create a new configure context to perform additional checks.

Example of a typical Configure usage:

env = Environment()
conf = Configure(env)
if not conf.CheckCHeader("math.h"):
print("We really need math.h!")
Exit(1)
if conf.CheckLibWithHeader("qt", "qapp.h", "c++", "QApplication qapp(0,0);"):
# do stuff for qt - usage, e.g.
conf.env.Append(CPPFLAGS="-DWITH_QT")
env = conf.Finish()

A configure context has the following predefined methods which can be used to perform
checks. Where language is a required or optional parameter, the choice can currently be C
or C++. The spellings accepted for C are “C” or “c”; for C++ the value can be “CXX”,
“cxx”, “C++” or “c++”.

SConf.CheckHeader(context, header, [include_quotes, language]),
context.CheckHeader(header, [include_quotes, language])
Checks if header is usable in the specified language. header may be a list, in which
case the last item in the list is the header file to be checked, and the previous list
items are header files whose #include lines should precede the header line being
checked for. The optional argument include_quotes must be a two character string,
where the first character denotes the opening quote and the second character denotes
the closing quote. By default, both characters are " (double quote). The optional
argument language should be either C or C++ and selects the compiler to be used for
the check. Returns a boolean indicating success or failure.

SConf.CheckCHeader(context, header, [include_quotes]), context.CheckCHeader(header,
[include_quotes])
This is a wrapper around SConf.CheckHeader which checks if header is usable in the C
language. header may be a list, in which case the last item in the list is the header
file to be checked, and the previous list items are header files whose #include lines
should precede the header line being checked for. The optional argument include_quotes
must be a two character string, where the first character denotes the opening quote
and the second character denotes the closing quote. By default, both characters are "
(double quote). Returns a boolean indicating success or failure.

SConf.CheckCXXHeader(context, header, [include_quotes]), context.CheckCXXHeader(header,
[include_quotes])
This is a wrapper around SConf.CheckHeader which checks if header is usable in the C++
language. header may be a list, in which case the last item in the list is the header
file to be checked, and the previous list items are header files whose #include lines
should precede the header line being checked for. The optional argument include_quotes
must be a two character string, where the first character denotes the opening quote
and the second character denotes the closing quote. By default, both characters are "
(double quote). Returns a boolean indicating success or failure.

SConf.CheckFunc(context, function_name, [header, language]),
context.CheckFunc(function_name, [header, language])
Checks if the specified C or C++ library function is available based on the context's
local environment settings (that is, using the values of CFLAGS, CPPFLAGS, LIBS or
other relevant construction variables).

function_name is the name of the function to check for. The optional header argument
is a string that will be placed at the top of the test file that will be compiled to
check if the function exists; the default is:

#ifdef __cplusplus
extern "C"
#endif
char function_name();

Returns an empty string on success, a string containing an error message on failure.

SConf.CheckLib(context, [library, symbol, header, language, autoadd=True]),
context.CheckLib([library, symbol, header, language, autoadd=True])
Checks if library provides symbol. If autoadd is true (the default) and the library
provides the specified symbol, appends the library to the LIBS construction variable
library may also be None (the default), in which case symbol is checked with the
current LIBS variable, or a list of library names, in which case each library in the
list will be checked for symbol. If symbol is not set or is None, then SConf.CheckLib
just checks if you can link against the specified library. Note though it is legal
syntax, it would not be very useful to call this method with library and symbol both
omitted or None. Returns a boolean indicating success or failure.

SConf.CheckLibWithHeader(context, library, header, language, [call, autoadd=True]),
context.CheckLibWithHeader(library, header, language, [call, autoadd=True])
Provides a more sophisticated way to check against libraries then the SConf.CheckLib
call. library specifies the library or a list of libraries to check. header
specifies a header to check for. header may be a list, in which case the last item in
the list is the header file to be checked, and the previous list items are header
files whose #include lines should precede the header line being checked for. call can
be any valid expression (with a trailing ';'). If call is not set, the default simply
checks that you can link against the specified library. autoadd (default true)
specifies whether to add the library to the environment if the check succeeds. Returns
a boolean indicating success or failure.

SConf.CheckType(context, type_name, [includes, language]), context.CheckType(type_name,
[includes, language])
Checks for the existence of a type defined by typedef. type_name specifies the
typedef name to check for. includes is a string containing one or more #include lines
that will be inserted into the program that will be run to test for the existence of
the type. Example:

sconf.CheckType('foo_type', '#include "my_types.h"', 'C++')

Returns an empty string on success, a string containing an error message on failure.

SConf.CheckCC(context), context.CheckCC()
Checks whether the C compiler (as defined by the CC construction variable) works by
trying to compile a small source file. Returns a boolean indicating success or
failure.

By default, SCons only detects if there is a program with the correct name, not if it
is a functioning compiler.

This uses the exact same command as the one used by the object builder for C source
files, so it can be used to detect if a particular compiler flag works or not.

SConf.CheckCXX(context), context.CheckCXX()
Checks whether the C++ compiler (as defined by the CXX construction variable) works by
trying to compile a small source file. By default, SCons only detects if there is a
program with the correct name, not if it is a functioning compiler. Returns a boolean
indicating success or failure.

This uses the exact same command as the one used by the object builder for C++ source
files, so it can be used to detect if a particular compiler flag works or not.

SConf.CheckSHCC(context), context.CheckSHCC()
Checks whether the shared-object C compiler (as defined by the SHCC construction
variable) works by trying to compile a small source file. By default, SCons only
detects if there is a program with the correct name, not if it is a functioning
compiler. Returns a boolean indicating success or failure.

This uses the exact same command as the one used by the object builder for C source
file, so it can be used to detect if a particular compiler flag works or not. This
does not check whether the object code can be used to build a shared library, only
that the compilation (not link) succeeds.

SConf.CheckSHCXX(context), context.CheckSHCXX()
Checks whether the shared-object C++ compiler (as defined by the SHCXX construction
variable) works by trying to compile a small source file. By default, SCons only
detects if there is a program with the correct name, not if it is a functioning
compiler. Returns a boolean indicating success or failure.

This uses the exact same command as the one used by the object builder for C++ source
files, so it can be used to detect if a particular compiler flag works or not. This
does not check whether the object code can be used to build a shared library, only
that the compilation (not link) succeeds.

SConf.CheckTypeSize(context, type_name, [header, language, expect]),
context.CheckTypeSize(type_name, [header, language, expect])
Checks for the size of a type defined by typedef. type_name specifies the typedef
name to check for. The optional header argument is a string that will be placed at the
top of the test file that will be compiled to check if the type exists; the default is
empty. If the optional expect, is supplied, it should be an integer size;
CheckTypeSize will fail unless type_name is actually that size. Returns the size in
bytes, or zero if the type was not found (or if the size did not match expect).

For example,

CheckTypeSize('short', expect=2)

will return the size 2 only if short is actually two bytes.

SConf.CheckDeclaration(context, symbol, [includes, language]),
context.CheckDeclaration(symbol, [includes, language])
Checks if the specified symbol is declared. includes is a string containing one or
more #include lines that will be inserted into the program that will be run to test
for the existence of the symbol. Returns a boolean indicating success or failure.

SConf.Define(context, symbol, [value, comment]), context.Define(symbol, [value, comment])
This function does not check for anything, but defines a preprocessor symbol that will
be added to the configuration header file. It is the equivalent of AC_DEFINE, and
defines the symbol name with the optional value and the optional comment comment.

Define Examples:

env = Environment()
conf = Configure(env)

# Puts the following line in the config header file:
# #define A_SYMBOL
conf.Define("A_SYMBOL")

# Puts the following line in the config header file:
# #define A_SYMBOL 1
conf.Define("A_SYMBOL", 1)

Be careful about quoting string values, though:

env = Environment()
conf = Configure(env)

# Puts the following line in the config header file:
# #define A_SYMBOL YA
conf.Define("A_SYMBOL", "YA")

# Puts the following line in the config header file:
# #define A_SYMBOL "YA"
conf.Define("A_SYMBOL", '"YA"')

For comment:

env = Environment()
conf = Configure(env)

# Puts the following lines in the config header file:
# /* Set to 1 if you have a symbol */
# #define A_SYMBOL 1
conf.Define("A_SYMBOL", 1, "Set to 1 if you have a symbol")

You can define your own custom checks in addition to the predefined checks. You pass a
dictionary of these to the Configure function as the custom_tests argument. This
dictionary maps the names of the checks to the user defined Python callables (either
Python functions or class instances implementing a __call__ method). Each custom check
will be called with a first argument of a CheckContext, instance followed by the
arguments, which must be supplied by the user of the check. A CheckContext instance
defines the following methods:

context.Message(text)
Displays a message, as an indicator of progess. text will be displayed, e.g.
Checking for library X.... Usually called before the check is started.

context.Result(res)
Displays a “result” message, as an indicator of progress. res can be either an
integer or a string. If an integer, displays yes (if res evaluates True) or no (if res
evaluates False). If a string, it is displayed as-is. Usually called after the check
has completed.

context.TryCompile(text, extension='')
Checks if a file with the specified extension (e.g. '.c') containing text can be
compiled using the environment's Object builder. Returns a boolean indicating success
or failure.

context.TryLink(text, extension='')
Checks, if a file with the specified extension (e.g. '.c') containing text can be
compiled using the environment's Program builder. Returns a boolean indicating success
or failure.

context.TryRun(text, extension='')
Checks if a file with the specified extension (e.g. '.c') containing text can be
compiled using the environment's Program builder. On success, the program is run. If
the program executes successfully (that is, its return status is 0), a tuple (1,
outputStr) is returned, where outputStr is the standard output of the program. If the
program fails execution (its return status is non-zero), then (0, '') is returned.

context.TryAction(action, [text, extension=''])
Checks if the specified action with an optional source file (contents text, extension
extension) can be executed. action may be anything which can be converted to a scons
Action. On success, (1, outputStr) is returned, where outputStr is the content of the
target file. On failure (0, '') is returned.

context.TryBuild(builder[, text, extension=''])
Low level implementation for testing specific builds; the methods above are based on
this method. Given the Builder instance builder and the optional text of a source file
with optional extension, returns a boolean indicating success or failure. In addition,
context.lastTarget is set to the build target node if the build was successful.

Example of implementing and using custom tests:

def CheckQt(context, qtdir):
context.Message( 'Checking for qt ...' )
lastLIBS = context.env['LIBS']
lastLIBPATH = context.env['LIBPATH']
lastCPPPATH= context.env['CPPPATH']
context.env.Append(LIBS='qt', LIBPATH=qtdir + '/lib', CPPPATH=qtdir + '/include')
ret = context.TryLink("""
#include <qapp.h>
int main(int argc, char **argv) {
QApplication qapp(argc, argv);
return 0;
}
""")
if not ret:
context.env.Replace(LIBS=lastLIBS, LIBPATH=lastLIBPATH, CPPPATH=lastCPPPATH)
context.Result( ret )
return ret

env = Environment()
conf = Configure(env, custom_tests={'CheckQt': CheckQt})
if not conf.CheckQt('/usr/lib/qt'):
print('We really need qt!')
Exit(1)
env = conf.Finish()

Command-Line Construction Variables
Often when building software, some variables need to be specified at build time. For
example, libraries needed for the build may be in non-standard locations, or site-specific
compiler options may need to be passed to the compiler. SCons provides a Variables object
to support overriding construction variables on the command line:

scons VARIABLE=foo

The variable values can also be specified in an SConscript file.

To obtain the object for manipulating values, call the Variables function:

Variables([files, [args]])
If files is a file or list of files, those are executed as Python scripts, and the
values of (global) Python variables set in those files are added as construction
variables in the Default Environment. If no files are specified, or the files argument
is None, then no files will be read. The following example file contents could be used
to set an alternative C compiler:

CC = 'my_cc'

If args is specified, it is a dictionary of values that will override anything read
from files. it is primarily intended to be passed the ARGUMENTS dictionary that holds
variables specified on the command line. Example:

vars = Variables('custom.py')
vars = Variables('overrides.py', ARGUMENTS)
vars = Variables(None, {FOO:'expansion', BAR:7})

Variables objects have the following methods:

vars.Add(key, [help, default, validator, converter])
Add a customizable construction variable to the Variables object. key is the name of
the variable. help is the help text for the variable. default is the default value
of the variable; if the default value is None and there is no explicit value
specified, the construction variable will not be added to the construction
environment. If set, validator is called to validate the value of the variable. A
function supplied as a validator shall accept arguments: key, value, and env. The
recommended way to handle an invalid value is to raise an exception (see example
below). If set, converter is called to convert the value before putting it in the
environment, and should take either a value, or the value and environment, as
parameters. The converter function must return a value, which will be converted into a
string before being validated by the validator (if any) and then added to the
construction environment.

Examples:

vars.Add('CC', help='The C compiler')

def valid_color(key, val, env):
if not val in ['red', 'blue', 'yellow']:
raise Exception("Invalid color value '%s'" % val)

vars.Add('COLOR', validator=valid_color)

vars.AddVariables(args)
A convenience method that adds multiple customizable construction variables to a
Variables object in one call; equivalent to calling Add multiple times. The args are
tuples (or lists) that contain the arguments for an individual call to the Add method.
Since tuples are not Python mappings, the arguments cannot use the keyword form, but
rather are positional arguments as documented for Add: a required name, the rest
optional but must be in the specified in order if used.

opt.AddVariables(
("debug", "", 0),
("CC", "The C compiler"),
("VALIDATE", "An option for testing validation", "notset", validator, None),
)

vars.Update(env, [args])
Update a construction environment env with the customized construction variables . Any
specified variables that are not configured for the Variables object will be saved and
may be retrieved using the UnknownVariables method, below.

Normally this method is not called directly, but rather invoked indirectly by passing
the Variables object to the Environment function:

env = Environment(variables=vars)

vars.UnknownVariables()
Returns a dictionary containing any variables that were specified either in the files
or the dictionary with which the Variables object was initialized, but for which the
Variables object was not configured.

env = Environment(variables=vars)
for key, value in vars.UnknownVariables():
print("unknown variable: %s=%s" % (key, value))

vars.Save(filename, env)
Save the currently set variables into a script file named by filename that can be used
on the next invocation to automatically load the current settings. This method
combined with the Variables method can be used to support caching of variables between
runs.

env = Environment()
vars = Variables(['variables.cache', 'custom.py'])
vars.Add(...)
vars.Update(env)
vars.Save('variables.cache', env)

vars.GenerateHelpText(env, [sort])
Generate help text documenting the customizable construction variables, suitable for
passing in to the Help function. env is the construction environment that will be
used to get the actual values of the customizable variables. If the (optional) value
of sort is callable, it is used as a comparison function to determine how to sort the
added variables. This function must accept two arguments, compare them, and return a
negative integer if the first is less-than the second, zero for equality, or a
positive integer for greater-than. Optionally a Boolean value of True for sort will
cause a standard alphabetical sort to be performed.

Help(vars.GenerateHelpText(env))

def cmp(a, b):
return (a > b) - (a < b)

Help(vars.GenerateHelpText(env, sort=cmp))

vars.FormatVariableHelpText(env, opt, help, default, actual)
Returns a formatted string containing the printable help text for one option. It is
normally not called directly, but is called by the GenerateHelpText method to create
the returned help text. It may be overridden with your own function that takes the
arguments specified above and returns a string of help text formatted to your liking.
Note that GenerateHelpText will not put any blank lines or extra characters in between
the entries, so you must add those characters to the returned string if you want the
entries separated.

def my_format(env, opt, help, default, actual):
fmt = "\n%s: default=%s actual=%s (%s)\n"
return fmt % (opt, default, actual, help)
vars.FormatVariableHelpText = my_format

To make it more convenient to work with customizable Variables, scons provides a number of
functions that make it easy to set up various types of Variables. Each of these return a
tuple ready to be passed to the Add or AddVariables method:

BoolVariable(key, help, default)
Returns a tuple of arguments to set up a Boolean option. The option will use the
specified name key, have a default value of default, and help will form the
descriptive part of the help text. The option will interpret the values y, yes, t,
true, 1, on and all as true, and the values n, no, f, false, 0, off and none as false.

EnumVariable(key, help, default, allowed_values, [map, ignorecase])
Returns a tuple of arguments to set up an option whose value may be one of a specified
list of legal enumerated values. The option will use the specified name key, have a
default value of default, and help will form the descriptive part of the help text.
The option will only support those values in the allowed_values list. The optional map
argument is a dictionary that can be used to convert input values into specific legal
values in the allowed_values list. If the value of ignore_case is 0 (the default),
then the values are case-sensitive. If the value of ignore_case is 1, then values will
be matched case-insensitively. If the value of ignore_case is 2, then values will be
matched case-insensitively, and all input values will be converted to lower case.

ListVariable(key, help, default, names, [map])
Returns a tuple of arguments to set up an option whose value may be one or more of a
specified list of legal enumerated values. The option will use the specified name key,
have a default value of default, and help will form the descriptive part of the help
text. The option will only accept the values “all”, “none”, or the values in the names
list. More than one value may be specified, separated by commas. The default may be a
string of comma-separated default values, or a list of the default values. The
optional map argument is a dictionary that can be used to convert input values into
specific legal values in the names list. (Note that the additional values accepted
through the use of a map are not reflected in the generated help message).

PackageVariable(key, help, default)
Returns a tuple of arguments to set up an option whose value is a path name of a
package that may be enabled, disabled or given an explicit path name. The option will
use the specified name key, have a default value of default, and help will form the
descriptive part of the help text. The option will support the values yes, true, on,
enable or search, in which case the specified default will be used, or the option may
be set to an arbitrary string (typically the path name to a package that is being
enabled). The option will also support the values no, false, off or disable to disable
use of the specified option.

PathVariable(key, help, default, [validator])
Returns a tuple of arguments to set up an option whose value is expected to be a path
name. The option will use the specified name key, have a default value of default, and
help will form the descriptive part of the help text. An additional validator may be
specified that will be called to verify that the specified path is acceptable. SCons
supplies the following ready-made validators:

PathVariable.PathExists
Verify that the specified path exists (this the default behavior if no validator
is supplied).

PathVariable.PathIsFile
Verify that the specified path exists and is a regular file.

PathVariable.PathIsDir
Verify that the specified path exists and is a directory.

PathVariable.PathIsDirCreate
Verify that the specified path exists and is a directory; if it does not exist,
create the directory.

PathVariable.PathAccept
Accept the specific path name argument without validation, suitable for when you
want your users to be able to specify a directory path that will be created as
part of the build process, for example.

You may supply your own validator function, which must accept three arguments (key,
the name of the variable to be set; val, the specified value being checked; and env,
the construction environment) and should raise an exception if the specified value is
not acceptable.

These functions make it convenient to create a number of variables with consistent
behavior in a single call to the AddVariables method:

vars.AddVariables(
BoolVariable(
"warnings",
help="compilation with -Wall and similar",
default=1,
),
EnumVariable(
"debug",
help="debug output and symbols",
default="no",
allowed_values=("yes", "no", "full"),
map={},
ignorecase=0, # case sensitive
),
ListVariable(
"shared",
help="libraries to build as shared libraries",
default="all",
names=list_of_libs,
),
PackageVariable(
"x11",
help="use X11 installed here (yes = search some places)",
default="yes",
),
PathVariable(
"qtdir",
help="where the root of Qt is installed",
default=qtdir),
PathVariable(
"foopath",
help="where the foo library is installed",
default=foopath,
validator=PathVariable.PathIsDir,
),
)

File and Directory Nodes
The File and Dir functions/methods return File and Directory Nodes, respectively. Such
nodes are Python objects with several user-visible attributes and methods that are often
useful to access in SConscript files:

n.path
The build path of the given file or directory. This path is relative to the top-level
directory (where the SConstruct file is found). The build path is the same as the
source path if variant_dir is not being used.

n.abspath
The absolute build path of the given file or directory.

n.srcnode()
The srcnode method returns another File or Directory Node representing the source path
of the given File or Directory Node.

For example:

# Get the current build dir's path, relative to top.
Dir('.').path
# Current dir's absolute path
Dir('.').abspath
# Next line is always '.', because it is the top dir's path relative to itself.
Dir('#.').path
File('foo.c').srcnode().path # source path of the given source file.

# Builders also return File objects:
foo = env.Program('foo.c')
print("foo will be built in", foo.path)

File and Directory Node objects have methods to create File and Directory Nodes relative
to the original Node.

If the object is a Directory Node, these methods will place the the new Node within the
directory the Node represents:

d.Dir(name)
Returns a directory Node for a subdirectory of d named name.

d.File(name)
Returns a file Node for a file within d named name.

d.Entry(name)
Returns an unresolved Node within d named name.

If the object is a File Node, these methods will place the the new Node in the same
directory as the one the Node represents:

f.Dir(name)
Returns a directory named name within the parent directory of f.

f.File(name)
Returns a file named name within the parent directory of f.

f.Entry(name)
Returns an unresolved Node named name within the parent directory of f.

For example:

# Get a Node for a file within a directory
incl = Dir('include')
f = incl.File('header.h')

# Get a Node for a subdirectory within a directory
dist = Dir('project-3.2.1')
src = dist.Dir('src')

# Get a Node for a file in the same directory
cfile = File('sample.c')
hfile = cfile.File('sample.h')

# Combined example
docs = Dir('docs')
html = docs.Dir('html')
index = html.File('index.html')
css = index.File('app.css')

EXTENDING SCONS

   Builder Objects
       scons can be extended to build different types of targets by adding new Builder objects to
       a construction environment.  In general, you should only need to add a new Builder object
       when you want to build a new type of file or other external target. If you just want to
       invoke a different compiler or other tool to build Program, Object, Library, or any other
       type of output file for which scons already has an existing Builder, it is generally much
       easier to use those existing Builders in a construction environment that sets the
       appropriate construction variables (CC, LINK, etc.).

       Builder objects are created using the Builder factory function. The Builder function
       accepts the following keyword arguments:

       action
           The command line string used to build the target from the source.  action can also be:
           a list of strings representing the command to be executed and its arguments (suitable
           for enclosing white space in an argument), a dictionary mapping source file name
           suffixes to any combination of command line strings (if the builder should accept
           multiple source file extensions), a Python function; an Action object (see the next
           section); or a list of any of the above.

           An action function takes three arguments:
               source - a list of source nodes;.
               target - a list of target nodes;.
               env - the construction environment.
           The action and generator arguments must not both be used for the same Builder.

       prefix
           The prefix that will be prepended to the target file name.  prefix may be:

           •   a string

           •   a callable object - a function or other callable that takes two arguments (a
               construction environment and a list of sources) and returns a prefix

           •   a dictionary - specifies a mapping from a specific source suffix (of the first
               source specified) to a corresponding target prefix. Both the source suffix and
               target prefix specifications may use environment variable substitution, and the
               target prefix (the 'value' entries in the dictionary) may also be a callable
               object. The default target prefix may be indicated by a dictionary entry with a
               key value of None.

               b = Builder("build_it < $SOURCE > $TARGET",
                           prefix = "file-")

               def gen_prefix(env, sources):
                   return "file-" + env['PLATFORM'] + '-'
               b = Builder("build_it < $SOURCE > $TARGET",
                           prefix = gen_prefix)

               b = Builder("build_it < $SOURCE > $TARGET",
                           suffix = { None: "file-",
                                      "$SRC_SFX_A": gen_prefix })

       suffix
           The suffix that will be appended to the target file name. This may be specified in the
           same manner as the prefix above. If the suffix is a string, then scons will append a
           '.' to the beginning of the suffix if it's not already there. The string returned by
           callable object (or obtained from the dictionary) is untouched and must append its own
           '.' to the beginning if one is desired.

               b = Builder("build_it < $SOURCE > $TARGET"
                           suffix = "-file")

               def gen_suffix(env, sources):
                   return "." + env['PLATFORM'] + "-file"
               b = Builder("build_it < $SOURCE > $TARGET",
                           suffix = gen_suffix)

               b = Builder("build_it < $SOURCE > $TARGET",
                           suffix = { None: ".sfx1",
                                      "$SRC_SFX_A": gen_suffix })

       ensure_suffix
           When set to any true value, causes scons to add the target suffix specified by the
           suffix keyword to any target strings that have a different suffix. (The default
           behavior is to leave untouched any target file name that looks like it already has any
           suffix.)

               b1 = Builder("build_it < $SOURCE > $TARGET"
                            suffix = ".out")
               b2 = Builder("build_it < $SOURCE > $TARGET"
                            suffix = ".out",
                            ensure_suffix)
               env = Environment()
               env['BUILDERS']['B1'] = b1
               env['BUILDERS']['B2'] = b2

               # Builds "foo.txt" because ensure_suffix is not set.
               env.B1('foo.txt', 'foo.in')

               # Builds "bar.txt.out" because ensure_suffix is set.
               env.B2('bar.txt', 'bar.in')

       src_suffix
           The expected source file name suffix. This may be a string or a list of strings.

       target_scanner
           A Scanner object that will be invoked to find implicit dependencies for this target
           file. This keyword argument should be used for Scanner objects that find implicit
           dependencies based only on the target file and the construction environment, not for
           implicit dependencies based on source files. See the section called “Scanner Objects”
           for information about creating Scanner objects.

       source_scanner
           A Scanner object that will be invoked to find implicit dependencies in any source
           files used to build this target file. This is where you would specify a scanner to
           find things like #include lines in source files. The pre-built DirScanner Scanner
           object may be used to indicate that this Builder should scan directory trees for
           on-disk changes to files that scons does not know about from other Builder or function
           calls. See the section called “Scanner Objects” for information about creating your
           own Scanner objects.

       target_factory
           A factory function that the Builder will use to turn any targets specified as strings
           into SCons Nodes. By default, SCons assumes that all targets are files. Other useful
           target_factory values include Dir, for when a Builder creates a directory target, and
           Entry, for when a Builder can create either a file or directory target.

           Example:

               MakeDirectoryBuilder = Builder(action=my_mkdir, target_factory=Dir)
               env = Environment()
               env.Append(BUILDERS={'MakeDirectory': MakeDirectoryBuilder})
               env.MakeDirectory('new_directory', [])

           Note that the call to this MakeDirectory Builder needs to specify an empty source list
           to make the string represent the builder's target; without that, it would assume the
           argument is the source, and would try to deduce the target name from it, which in the
           absence of an automatically-added prefix or suffix would lead to a matching target and
           source name and a circular dependency.

       source_factory
           A factory function that the Builder will use to turn any sources specified as strings
           into SCons Nodes. By default, SCons assumes that all source are files. Other useful
           source_factory values include Dir, for when a Builder uses a directory as a source,
           and Entry, for when a Builder can use files or directories (or both) as sources.

           Example:

               CollectBuilder = Builder(action=my_mkdir, source_factory=Entry)
               env = Environment()
               env.Append(BUILDERS={'Collect': CollectBuilder})
               env.Collect('archive', ['directory_name', 'file_name'])

       emitter
           A function or list of functions to manipulate the target and source lists before
           dependencies are established and the target(s) are actually built.  emitter can also
           be a string containing a construction variable to expand to an emitter function or
           list of functions, or a dictionary mapping source file suffixes to emitter functions.
           (Only the suffix of the first source file is used to select the actual emitter
           function from an emitter dictionary.)

           An emitter function takes three arguments:
               source - a list of source nodes.
               target - a list of target nodes.
               env - the construction environment.
           An emitter must return a tuple containing two lists, the list of targets to be built
           by this builder, and the list of sources for this builder.

           Example:

               def e(target, source, env):
                   return (target + ['foo.foo'], source + ['foo.src'])

               # Simple association of an emitter function with a Builder.
               b = Builder("my_build < $TARGET > $SOURCE",
                           emitter = e)

               def e2(target, source, env):
                   return (target + ['bar.foo'], source + ['bar.src'])

               # Simple association of a list of emitter functions with a Builder.
               b = Builder("my_build < $TARGET > $SOURCE",
                           emitter = [e, e2])

               # Calling an emitter function through a construction variable.
               env = Environment(MY_EMITTER=e)
               b = Builder("my_build < $TARGET > $SOURCE",
                           emitter='$MY_EMITTER')

               # Calling a list of emitter functions through a construction variable.
               env = Environment(EMITTER_LIST=[e, e2])
               b = Builder("my_build < $TARGET > $SOURCE",
                           emitter='$EMITTER_LIST')

               # Associating multiple emitters with different file
               # suffixes using a dictionary.
               def e_suf1(target, source, env):
                   return (target + ['another_target_file'], source)
               def e_suf2(target, source, env):
                   return (target, source + ['another_source_file'])
               b = Builder("my_build < $TARGET > $SOURCE",
                           emitter={'.suf1' : e_suf1,
                                    '.suf2' : e_suf2})

       multi
           Specifies whether this builder is allowed to be called multiple times for the same
           target file(s). The default is 0, which means the builder can not be called multiple
           times for the same target file(s). Calling a builder multiple times for the same
           target simply adds additional source files to the target; it is not allowed to change
           the environment associated with the target, specify additional environment overrides,
           or associate a different builder with the target.

       env
           A construction environment that can be used to fetch source code using this Builder.
           (Note that this environment is not used for normal builds of normal target files,
           which use the environment that was used to call the Builder for the target file.)

       generator
           A function that returns a list of actions that will be executed to build the target(s)
           from the source(s). The returned action(s) may be an Action object, or anything that
           can be converted into an Action object (see the next section).

           The generator function takes four arguments:
               source - A list of source nodes;.
               target - A list of target nodes;.
               env - the construction environment.
               for_signature -
                   A Boolean value that specifies
                   whether the generator is being called
                   for generating a build signature
                   (as opposed to actually executing the command).
           Example:

               def g(source, target, env, for_signature):
                   return [["gcc", "-c", "-o"] + target + source]

               b = Builder(generator=g)

           The generator and action arguments must not both be used for the same Builder.

       src_builder
           Specifies a builder to use when a source file name suffix does not match any of the
           suffixes of the builder. Using this argument produces a multi-stage builder.

       single_source
           Specifies that this builder expects exactly one source file per call. Giving more than
           one source file without target files results in implicitly calling the builder
           multiple times (once for each source given). Giving multiple source files together
           with target files results in a UserError exception.

       source_ext_match
           When the specified action argument is a dictionary, the default behavior when a
           builder is passed multiple source files is to make sure that the extensions of all the
           source files match. If it is legal for this builder to be called with a list of source
           files with different extensions, this check can be suppressed by setting
           source_ext_match to None or some other non-true value. When source_ext_match is
           disable, scons will use the suffix of the first specified source file to select the
           appropriate action from the action dictionary.

           In the following example, the setting of source_ext_match prevents scons from exiting
           with an error due to the mismatched suffixes of foo.in and foo.extra.

               b = Builder(action={'.in' : 'build $SOURCES > $TARGET'},
                           source_ext_match = None)

               env = Environment(BUILDERS={'MyBuild':b})
               env.MyBuild('foo.out', ['foo.in', 'foo.extra'])

       env
           A construction environment that can be used to fetch source code using this Builder.
           (Note that this environment is not used for normal builds of normal target files,
           which use the environment that was used to call the Builder for the target file.)

               b = Builder(action="build < $SOURCE > $TARGET")
               env = Environment(BUILDERS={'MyBuild' : b})
               env.MyBuild('foo.out', 'foo.in', my_arg='xyzzy')

       chdir
           A directory from which scons will execute the action(s) specified for this Builder. If
           the chdir argument is a string or a directory Node, scons will change to the specified
           directory. If the chdir is not a string or Node and is non-zero, then scons will
           change to the target file's directory.

           Note that scons will not automatically modify its expansion of construction variables
           like $TARGET and $SOURCE when using the chdir keyword argument--that is, the expanded
           file names will still be relative to the top-level directory containing the SConstruct
           file, and consequently incorrect relative to the chdir directory. Builders created
           using chdir keyword argument, will need to use construction variable expansions like
           ${TARGET.file} and ${SOURCE.file} to use just the filename portion of the targets and
           source.

               b = Builder(action="build < ${SOURCE.file} > ${TARGET.file}",
                           chdir=1)
               env = Environment(BUILDERS={'MyBuild' : b})
               env.MyBuild('sub/dir/foo.out', 'sub/dir/foo.in')

               Warning
               Python only keeps one current directory location even if there are multiple
               threads. This means that use of the chdir argument will not work with the SCons -j
               option, because individual worker threads spawned by SCons interfere with each
               other when they start changing directory.

       Any additional keyword arguments supplied when a Builder object is created (that is, when
       the Builder function is called) will be set in the executing construction environment when
       the Builder object is called. The canonical example here would be to set a construction
       variable to the repository of a source code system.

       Any additional keyword arguments supplied when a Builder object is called will only be
       associated with the target created by that particular Builder call (and any other files
       built as a result of the call).

       These extra keyword arguments are passed to the following functions: command generator
       functions, function Actions, and emitter functions.

   Action Objects
       The Builder function will turn its action keyword argument into an appropriate internal
       Action object. You can also explicitly create Action objects for passing to Builder, or
       other functions that take actions as arguments, by calling the Action factory function.
       This can be used to configure an Action object more flexibly, or it may simply be more
       efficient than letting each separate Builder object create a separate Action when multiple
       Builder objects need to do the same thing.

       The Action factory function returns an appropriate object for the action represented by
       the type of the action argument (the first positional parmeter):

       •   If the action argument is already an Action object, the object is simply returned.

       •   If the action argument is a string, a command-line Action is returned. If such a
           string begins with @, it indicates printing of the command line is to be suppressed.
           If the string begins with - (hyphen), it indicates the exit status from the specified
           command is to be ignored, allowing execution to continue even if the command reports
           failure:

               Action('$CC -c -o $TARGET $SOURCES')

               # Doesn't print the line being executed.
               Action('@build $TARGET $SOURCES')

               # Ignores return value
               Action('-build $TARGET $SOURCES')

       •   If the action argument is a list, then a list of Action objects is returned. An Action
           object is created as necessary for each element in the list. If an element within the
           list is itself a list, the internal list is taken as the command and arguments to be
           executed via the command line. This allows white space to be enclosed in an argument
           rather than taken as a separator by defining a command in a list within a list:

               Action([['cc', '-c', '-DWHITE SPACE', '-o', '$TARGET', '$SOURCES']])

       •   If the action argument is a Python function, a function Action is returned. The Python
           function must accept three keyword arguments:
               target -
                   a Node object representing the target file.
               source -
                   a Node object representing the source file.
               env -
                   the construction environment used for building the target file.
           The target and source arguments may be lists of Node objects if there is more than one
           target file or source file. The actual target and source file name(s) may be retrieved
           from their Node objects via the built-in Python str function:

               target_file_name = str(target)
               source_file_names = [str(x) for x in source]

           The function should return 0 or None to indicate a successful build of the target
           file(s). The function may raise an exception or return a non-zero exit status to
           indicate an unsuccessful build.

               def build_it(target=None, source=None, env=None):
                   # build the target from the source
                   return 0

               a = Action(build_it)

       •   If the action argument is not one of the above types, None is returned.

       As usual the environment method form env.Action will expand construction variables in any
       argument strings, including the action argument, at the time it is called, using the
       construction variables in the construction environment through which it was called. The
       global function form Action delays variable expansion until the Action object is actually
       used.

       The second argument to Action is optional and is used to define the output which is
       printed when the Action is actually performed. In the absence of this parameter, or if
       it's an empty string, a default output depending on the type of the action is used. For
       example, a command-line action will print the executed command. The argument must be
       either a Python function or a string:

       •   If the output argument is a function, it must return a string describing the action
           being executed. A function may also be specified using the strfunction keyword
           argument. The function must accept these three keyword arguments:
               source -
                   a Node object representing the source file.
               target -
                   a Node object representing the target file.
               env - the construction environment.
           The target and source arguments may be lists of Node objects if there is more than one
           target file or source file.

       •   If the output argument is a string, substitution is performed on it before it is
           printed. The output string may also be specified using the cmdstr keyword argument.
           The string typically contains variables, notably $TARGET(S) and $SOURCE(S), or
           consists of just a single variable, which is optionally defined somewhere else. SCons
           itself heavily uses the latter variant.

       Examples:

           def build_it(target, source, env):
               # build the target from the source
               return 0

           def string_it(target, source, env):
               return "building '%s' from '%s'" % (target[0], source[0])

           # Use a positional argument.
           f = Action(build_it, string_it)
           s = Action(build_it, "building '$TARGET' from '$SOURCE'")

           # Alternatively, use a keyword argument.
           f = Action(build_it, strfunction=string_it)
           s = Action(build_it, cmdstr="building '$TARGET' from '$SOURCE'")

           # You can provide a configurable variable.
           l = Action(build_it, '$STRINGIT')

       Any additional positional arguments, if present, may either be construction variables or
       lists of construction variables whose values will be included in the signature of the
       Action when deciding whether a target should be rebuilt because the action changed. Such
       variables may also be specified using the varlist keyword parameter; both positional and
       keyword forms may be present, and will be combined. This is necessary whenever you want a
       target to be rebuilt when a specific construction variable changes. This is not often
       needed for a string action, as the expanded variables will normally be part of the command
       line, but may be needed if a Python function action uses the value of a construction
       variable when generating the command line.

           def build_it(target, source, env):
               # build the target from the 'XXX' construction variable
               with open(target[0], 'w') as f:
                   f.write(env['XXX'])
               return 0

           # Use positional arguments.
           a = Action(build_it, '$STRINGIT', ['XXX'])

           # Alternatively, use a keyword argument.
           a = Action(build_it, varlist=['XXX'])

       The Action factory function can be passed the following optional keyword arguments to
       modify the Action object's behavior:

       chdir
           Specifies that scons will execute the action after changing to the specified
           directory. If the chdir argument is a string or a directory Node, scons will change to
           the specified directory. If the chdir argument is not a string or Node and is
           non-zero, then scons will change to the target file's directory.

           Note that scons will not automatically modify its expansion of construction variables
           like $TARGET and $SOURCE when using the chdir keyword argument--that is, the expanded
           file names will still be relative to the top-level directory containing the SConstruct
           file, and consequently incorrect relative to the chdir directory. Builders created
           using chdir keyword argument, will need to use construction variable expansions like
           ${TARGET.file} and ${SOURCE.file} to use just the filename portion of the targets and
           source. Example:

               a = Action("build < ${SOURCE.file} > ${TARGET.file}",
                          chdir=1)

       exitstatfunc
           A function that is passed the exit status (or return value) from the specified action
           and can return an arbitrary or modified value. This can be used, for example, to
           specify that an Action object's return value should be ignored under special
           conditions and SCons should, therefore, consider that the action always succeeds.
           Example:

               def always_succeed(s):
                   # Always return 0, which indicates success.
                   return 0

               a = Action("build < ${SOURCE.file} > ${TARGET.file}",
                          exitstatfunc=always_succeed)

       batch_key
           Specifies that the Action can create multiple target files by processing multiple
           independent source files simultaneously. (The canonical example is "batch compilation"
           of multiple object files by passing multiple source files to a single invocation of a
           compiler such as Microsoft's Visual C / C++ compiler.) If the batch_key argument
           evaluates True and is not a callable object, the configured Action object will cause
           scons to collect all targets built with the Action object and configured with the same
           construction environment into single invocations of the Action object's command line
           or function. Command lines will typically want to use the $CHANGED_SOURCES
           construction variable (and possibly $CHANGED_TARGETS as well) to only pass to the
           command line those sources that have actually changed since their targets were built.
           Example:

               a = Action('build $CHANGED_SOURCES', batch_key=True)

           The batch_key argument may also be a callable function that returns a key that will be
           used to identify different "batches" of target files to be collected for batch
           building. A batch_key function must accept the following arguments:
               action - The action object.
               env -
                   The construction environment configured for the target.
               target -
                   The list of targets for a particular configured action.
               source -
                   The list of source for a particular configured action.
           The returned key should typically be a tuple of values derived from the arguments,
           using any appropriate logic to decide how multiple invocations should be batched. For
           example, a batch_key function may decide to return the value of a specific
           construction variable from the env argument which will cause scons to batch-build
           targets with matching values of that variable, or perhaps return the Python id() of
           the entire construction environment, in which case scons will batch-build all targets
           configured with the same construction environment. Returning None indicates that the
           particular target should not be part of any batched build, but instead will be built
           by a separate invocation of action's command or function. Example:

               def batch_key(action, env, target, source):
                   tdir = target[0].dir
                   if tdir.name == 'special':
                       # Don't batch-build any target
                       # in the special/ subdirectory.
                       return None
                   return (id(action), id(env), tdir)
               a = Action('build $CHANGED_SOURCES', batch_key=batch_key)

   Miscellaneous Action Functions
       scons supplies a number of functions that arrange for various common file and directory
       manipulations to be performed. These are similar in concept to "tasks" in the Ant build
       tool, although the implementation is slightly different. These functions do not actually
       perform the specified action at the time the function is called, but rather are factory
       functions which return an Action object that can be executed at the appropriate time.

       In practice, there are two natural ways that these Action Functions are intended to be
       used.

       First, if you need to perform the action at the time the SConscript file is being read,
       you can use the Execute global function to do so:

           Execute(Touch('file'))

       Second, you can use these functions to supply Actions in a list for use by the env.Command
       method. This can allow you to perform more complicated sequences of file manipulation
       without relying on platform-specific external commands:

           env = Environment(TMPBUILD='/tmp/builddir')
           env.Command(
               target='foo.out',
               source='foo.in',
               action=[
                   Mkdir('$TMPBUILD'),
                   Copy('$TMPBUILD', '${SOURCE.dir}'),
                   "cd $TMPBUILD && make",
                   Delete('$TMPBUILD'),
               ],
           )

       Chmod(dest, mode)
           Returns an Action object that changes the permissions on the specified dest file or
           directory to the specified mode which can be octal or string, similar to the bash
           command. Examples:

               Execute(Chmod('file', 0o755))

               env.Command('foo.out', 'foo.in',
                           [Copy('$TARGET', '$SOURCE'),
                            Chmod('$TARGET', 0o755)])

               Execute(Chmod('file', "ugo+w"))

               env.Command('foo.out', 'foo.in',
                           [Copy('$TARGET', '$SOURCE'),
                            Chmod('$TARGET', "ugo+w")])

       Copy(dest, src)
           Returns an Action object that will copy the src source file or directory to the dest
           destination file or directory. Examples:

               Execute(Copy('foo.output', 'foo.input'))

               env.Command('bar.out', 'bar.in', Copy('$TARGET', '$SOURCE'))

       Delete(entry, [must_exist])
           Returns an Action that deletes the specified entry, which may be a file or a directory
           tree. If a directory is specified, the entire directory tree will be removed. If the
           must_exist flag is set to a true value, then a Python error will be raised if the
           specified entry does not exist; the default is false, that is, the Action will
           silently do nothing if the entry does not exist. Examples:

               Execute(Delete('/tmp/buildroot'))

               env.Command(
                   'foo.out',
                   'foo.in',
                   action=[
                       Delete('${TARGET.dir}'),
                       MyBuildAction,
                   ],
               )

               Execute(Delete('file_that_must_exist', must_exist=True))

       Mkdir(dir)
           Returns an Action that creates the specified directory dir. Examples:

               Execute(Mkdir('/tmp/outputdir'))

               env.Command(
                   'foo.out',
                   'foo.in',
                   action=[
                       Mkdir('/tmp/builddir'),
                       Copy('/tmp/builddir/foo.in', '$SOURCE'),
                       "cd /tmp/builddir && make",
                       Copy('$TARGET', '/tmp/builddir/foo.out'),
                   ],
               )

       Move(dest, src)
           Returns an Action that moves the specified src file or directory to the specified dest
           file or directory. Examples:

               Execute(Move('file.destination', 'file.source'))

               env.Command(
                   'output_file',
                   'input_file',
                   action=[MyBuildAction, Move('$TARGET', 'file_created_by_MyBuildAction')],
               )

       Touch(file)
           Returns an Action that updates the modification time on the specified file. Examples:

               Execute(Touch('file_to_be_touched'))

               env.Command('marker', 'input_file', action=[MyBuildAction, Touch('$TARGET')])

   Variable Substitution
       Before executing a command, scons performs construction variable substitution on the
       string that makes up the command line of the builder.  Construction variables to be
       interpolated are indicated in the string with a leading $, to distinguish them from plain
       text which is not to be substituted. Besides regular construction variables, scons
       provides the following special variables for each command execution:

       $CHANGED_SOURCES
           The file names of all sources of the build command that have changed since the target
           was last built.

       $CHANGED_TARGETS
           The file names of all targets that would be built from sources that have changed since
           the target was last built.

       $SOURCE
           The file name of the source of the build command, or the file name of the first source
           if multiple sources are being built.

       $SOURCES
           The file names of the sources of the build command.

       $TARGET
           The file name of the target being built, or the file name of the first target if
           multiple targets are being built.

       $TARGETS
           The file names of all targets being built.

       $UNCHANGED_SOURCES
           The file names of all sources of the build command that have not changed since the
           target was last built.

       $UNCHANGED_TARGETS
           The file names of all targets that would be built from sources that have not changed
           since the target was last built.

       Note that the above variables are reserved and may not be assigned to in the construction
       environment.

       For example, given the construction variables CC='cc', targets=['foo'] and
       sources=['foo.c', 'bar.c']:

           action='$CC -c -o $TARGET $SOURCES'

       would produce the command line:

           cc -c -o foo foo.c bar.c

       Variable names may be surrounded by curly braces ({}) to separate the name from
       surrounding characters which are not part of the name. Within the curly braces, a variable
       name may use Python list subscripting/slicing notation to select one or more items from a
       list. In the previous example, the string: ${SOURCES[1]} would produce:

           bar.c

       Additionally, a variable name may have the following modifiers appended within the
       enclosing curly braces to access properties of the interpolated string:
           base -
               The base path of the file name,
               including the directory path
               but excluding any suffix.

           dir - The name of the directory in which the file exists.
           file -  The file name, minus any directory portion.
           filebase - Like file but minus its suffix.
           suffix - Just the file suffix.
           abspath - The absolute path name of the file.
           posix -
               The path with directories separated by forward slashes
               (/).
               Sometimes necessary on Windows systems
               when a path references a file on other (POSIX) systems.

           windows -
               The path with directories separated by backslashes
               (\\).
               Sometimes necessary on POSIX-style systems
               when a path references a file on other (Windows) systems.
               win32 is a (deprecated) synonym for
               windows.

           srcpath -
               The directory and file name to the source file linked to this file through
               VariantDir().
               If this file isn't linked,
               it just returns the directory and filename unchanged.

           srcdir -
               The directory containing the source file linked to this file through
               VariantDir().
               If this file isn't linked,
               it just returns the directory part of the filename.

           rsrcpath -
               The directory and file name to the source file linked to this file through
               VariantDir().
               If the file does not exist locally but exists in a Repository,
               the path in the Repository is returned.
               If this file isn't linked, it just returns the
               directory and filename unchanged.

           rsrcdir -
               The Repository directory containing the source file linked to this file through
               VariantDir().
               If this file isn't linked,
               it just returns the directory part of the filename.

       For example, the specified target will expand as follows for the corresponding modifiers:

           $TARGET              => sub/dir/file.x
           ${TARGET.base}       => sub/dir/file
           ${TARGET.dir}        => sub/dir
           ${TARGET.file}       => file.x
           ${TARGET.filebase}   => file
           ${TARGET.suffix}     => .x
           ${TARGET.abspath}    => /top/dir/sub/dir/file.x

           SConscript('src/SConscript', variant_dir='sub/dir')
           $SOURCE              => sub/dir/file.x
           ${SOURCE.srcpath}    => src/file.x
           ${SOURCE.srcdir}     => src

           Repository('/usr/repository')
           $SOURCE              => sub/dir/file.x
           ${SOURCE.rsrcpath}   => /usr/repository/src/file.x
           ${SOURCE.rsrcdir}    => /usr/repository/src

       Modifiers can be combined, like ${TARGET.base.windows}, ${TARGET.srcpath.base),
       ${TARGET.file.suffix}, etc.

       Note that curly braces braces may also be used to enclose arbitrary Python code to be
       evaluated. (In fact, this is how the above modifiers are substituted, they are simply
       attributes of the Python objects that represent $TARGET, $SOURCES, etc.) See the section
       called “Python Code Substitution” below for more thorough examples of how this can be
       used.

       Lastly, a variable name may be a callable Python function associated with a construction
       variable in the environment. The function should accept four arguments:
           target - a list of target nodes
           source - a list of source nodes
           env - the construction environment
           for_signature -
               a Boolean value that specifies
               whether the function is being called
               for generating a build signature.

       SCons will insert whatever the called function returns into the expanded string:

           def foo(target, source, env, for_signature):
               return "bar"

           # Will expand $BAR to "bar baz"
           env=Environment(FOO=foo, BAR="$FOO baz")

       You can use this feature to pass arguments to a Python function by creating a callable
       class that stores one or more arguments in an object, and then uses them when the
       __call__() method is called. Note that in this case, the entire variable expansion must be
       enclosed by curly braces so that the arguments will be associated with the instantiation
       of the class:

           class foo:
               def __init__(self, arg):
                   self.arg = arg

               def __call__(self, target, source, env, for_signature):
                   return self.arg + " bar"

           # Will expand $BAR to "my argument bar baz"
           env=Environment(FOO=foo, BAR="${FOO('my argument')} baz")

       The special pseudo-variables $( and $) may be used to surround parts of a command line
       that may change without causing a rebuild--that is, which are not included in the
       signature of target files built with this command. All text between $( and $) will be
       removed from the command line before it is added to file signatures, and the $( and $)
       will be removed before the command is executed. For example, the command line:

           echo Last build occurred $( $TODAY $). > $TARGET

       would execute the command:

           echo Last build occurred $TODAY. > $TARGET

       but the command signature added to any target files would be:

           echo Last build occurred  . > $TARGET

   Python Code Substitution
       Any Python code within curly braces ({}) and introduced by the variable prefix $ will be
       evaluated using the Python eval statement, with the Python globals set to the current
       environment's set of construction variables, and the result substituted in. So in the
       following case:

           env['COND'] = 0
           env.Command('foo.out', 'foo.in',
               '''echo ${COND==1 and 'FOO' or 'BAR'} > $TARGET''')

       the command executed will be either

           echo FOO > foo.out

       or

           echo BAR > foo.out

       according to the current value of env['COND'] when the command is executed. The evaluation
       takes place when the target is being built, not when the SConscript is being read. So if
       env['COND'] is changed later in the SConscript, the final value will be used.

       Here's a more interesting example. Note that all of COND, FOO, and BAR are construction
       variables, and their values are substituted into the final command.  FOO is a list, so its
       elements are interpolated separated by spaces.

           env=Environment()
           env['COND'] = 0
           env['FOO'] = ['foo1', 'foo2']
           env['BAR'] = 'barbar'
           env.Command('foo.out', 'foo.in',
               'echo ${COND==1 and FOO or BAR} > $TARGET')

           # Will execute this:
           #  echo foo1 foo2 > foo.out

       SCons uses the following rules when converting construction variables into command lines:

       string
           When the value is a string it is interpreted as a space delimited list of command line
           arguments.

       list
           When the value is a list it is interpreted as a list of command line arguments. Each
           element of the list is converted to a string.

       other
           Anything that is not a list or string is converted to a string and interpreted as a
           single command line argument.

       newline
           Newline characters (\n) delimit lines. The newline parsing is done after all other
           parsing, so it is not possible for arguments (e.g. file names) to contain embedded
           newline characters.

   Scanner Objects
       You can use the Scanner function to define objects to scan new file types for implicit
       dependencies. The Scanner function accepts the following arguments:

       function
           This can be either:

           •   a Python function that will process the Node (file) and return a list of File
               Nodes representing the implicit dependencies (file names) found in the contents;
               or:

           •   a dictionary that maps keys (typically the file suffix, but see below for more
               discussion) to other Scanners that should be called.

           If the argument is a Python function, the function must accept three required
           arguments and an optional fourth:
               node -
                   The internal SCons node representing the file.
                   Use str(node)
                   to fetch the name of the file, and
                   node.get_contents()
                   to fetch the contents of the file as bytes or
                   node.get_text_contents()
                   to fetch the contents as text.
                   Note that the file is
                   not
                   guaranteed to exist before the scanner is called,
                   so the scanner function should check that
                   if there's any chance that the scanned file
                   might not exist
                   (for example, if it's built from other files).

               env - The construction environment for the scan.
               path -
                   A tuple (or list)
                   of directories that can be searched
                   for files.
                   This will usually be the tuple returned by the
                  path_function
                  argument (see below).

               arg -
                   The argument supplied when the scanner was created, if any
                   (default None.

       name
           The name of the Scanner. This is mainly used to identify the Scanner internally.

       argument
           An optional argument that, if specified, will be passed to the scanner function
           (described above) and the path function (specified below).

       skeys
           An optional list that can be used to determine which scanner should be used for a
           given Node. In the usual case of scanning for file names, this argument will be a list
           of suffixes for the different file types that this Scanner knows how to scan. If the
           argument is a string, then it will be expanded into a list by the current environment.

       path_function
           A Python function that takes four or five arguments: a construction environment, a
           Node for the directory containing the SConscript file in which the first target was
           defined, a list of target nodes, a list of source nodes, and an optional argument
           supplied when the scanner was created. The path_function returns a tuple of
           directories that can be searched for files to be returned by this Scanner object.
           (Note that the FindPathDirs function can be used to return a ready-made path_function
           for a given construction variable name, instead of having to write your own function
           from scratch.)

       node_class
           The class of Node that should be returned by this Scanner object. Any strings or other
           objects returned by the scanner function that are not of this class will be run
           through the function supplied by the node_factory argument.

       node_factory
           A Python function that will take a string or other object and turn it into the
           appropriate class of Node to be returned by this Scanner object.

       scan_check
           An optional Python function that takes two arguments, a Node (file) and a construction
           environment, and returns whether the Node should, in fact, be scanned for
           dependencies. This check can be used to eliminate unnecessary calls to the scanner
           function when, for example, the underlying file represented by a Node does not yet
           exist.

       recursive
           An optional flag that specifies whether this scanner should be re-invoked on the
           dependency files returned by the scanner. When this flag is not set, the Node
           subsystem will only invoke the scanner on the file being scanned, and not (for
           example) also on the files specified by the #include lines in the file being scanned.
           recursive may be a callable function, in which case it will be called with a list of
           Nodes found and should return a list of Nodes that should be scanned recursively; this
           can be used to select a specific subset of Nodes for additional scanning.

       Note that scons has a global SourceFileScanner object that is used by the Object,
       SharedObject and StaticObject builders to decide which scanner should be used for
       different file extensions. You can use the SourceFileScanner.add_scanner() method to add
       your own Scanner object to the SCons infrastructure that builds target programs or
       libraries from a list of source files of different types:

           def xyz_scan(node, env, path):
               contents = node.get_text_contents()
               # Scan the contents and return the included files.

           XYZScanner = Scanner(xyz_scan)

           SourceFileScanner.add_scanner('.xyz', XYZScanner)

           env.Program('my_prog', ['file1.c', 'file2.f', 'file3.xyz'])

SYSTEM-SPECIFIC BEHAVIOR

scons and its configuration files are very portable, due largely to its implementation in
Python. There are, however, a few portability issues waiting to trap the unwary.

.C file suffix
scons handles the upper-case .C file suffix differently, depending on the capabilities of
the underlying system. On a case-sensitive system such as Linux or UNIX, scons treats a
file with a .C suffix as a C++ source file. On a case-insensitive system such as Windows,
scons treats a file with a .C suffix as a C source file.

.F file suffix
scons handles the upper-case .F file suffix differently, depending on the capabilities of
the underlying system. On a case-sensitive system such as Linux or UNIX, scons treats a
file with a .F suffix as a Fortran source file that is to be first run through the
standard C preprocessor. On a case-insensitive system such as Windows, scons treats a file
with a .F suffix as a Fortran source file that should not be run through the C
preprocessor.

Windows: Cygwin Tools and Cygwin Python vs. Windows Pythons
Cygwin supplies a set of tools and utilities that let users work on a Windows system using
a more POSIX-like environment. The Cygwin tools, including Cygwin Python, do this, in
part, by sharing an ability to interpret UNIX-like path names. For example, the Cygwin
tools will internally translate a Cygwin path name like /cygdrive/c/mydir to an equivalent
Windows pathname of C:/mydir (equivalent to C:\mydir).

Versions of Python that are built for native Windows execution, such as the python.org and
ActiveState versions, do not have the Cygwin path name semantics. This means that using a
native Windows version of Python to build compiled programs using Cygwin tools (such as
gcc, bison and flex) may yield unpredictable results. "Mixing and matching" in this way
can be made to work, but it requires careful attention to the use of path names in your
SConscript files.

In practice, users can sidestep the issue by adopting the following rules: When using gcc,
use the Cygwin-supplied Python interpreter to run scons; when using Microsoft Visual C/C++
(or some other Windows compiler) use the python.org or Microsoft Store or ActiveState
version of Python to run scons.

Windows: scons.bat file
On Windows systems, scons is executed via a wrapper scons.bat file. This has (at least)
two ramifications:

First, Windows command-line users that want to use variable assignment on the command line
may have to put double quotes around the assignments:

scons "FOO=BAR" "BAZ=BLEH"

Second, the Cygwin shell does not recognize this file as being the same as an scons
command issued at the command-line prompt. You can work around this either by executing
scons.bat from the Cygwin command line, or by creating a wrapper shell script named scons.

MinGW
The MinGW bin directory must be in your PATH environment variable or the ENV['PATH']
construction variable for scons to detect and use the MinGW tools. When running under the
native Windows Python interpreter, scons will prefer the MinGW tools over the Cygwin
tools, if they are both installed, regardless of the order of the bin directories in the
PATH variable. If you have both MSVC and MinGW installed and you want to use MinGW instead
of MSVC, then you must explicitly tell scons to use MinGW by passing tools=['mingw'] to
the Environment function, because scons will prefer the MSVC tools over the MinGW tools.

ENVIRONMENT

In general, scons is not controlled by environment variables set in the shell used to
invoke it, leaving it up to the SConscript file author to import those if desired. However
the following variables are imported by scons itself if set:

SCONS_LIB_DIR
Specifies the directory that contains the scons Python module directory. Normally
scons can deduce this, but in some circumstances, such as working with a source
release, it may be necessary to specify (for example,
/home/aroach/scons-src-0.01/src/engine).

SCONSFLAGS
A string of options that will be used by scons in addition to those passed on the
command line.

SCONS_CACHE_MSVC_CONFIG
(Windows only). If set, save the shell environment variables generated when setting up
the Microsoft Visual C++ compiler (and/or Build Tools) to a file to give these
settings, which are expensive to generate, persistence across scons invocations. Use
of this option is primarily intended to aid performance in tightly controlled
Continuous Integration setups.

If set to a True-like value ("1", "true" or "True") will cache to a file named
.scons_msvc_cache in the user's home directory. If set to a pathname, will use that
pathname for the cache.

Note: use this cache with caution as it might be somewhat fragile: while each major
toolset version (e.g. Visual Studio 2017 vs 2019) and architecture pair will get
separate cache entries, if toolset updates cause a change to settings within a given
release series, scons will not detect the change and will reuse old settings. Remove
the cache file in case of problems with this. scons will ignore failures reading or
writing the file and will silently revert to non-cached behavior in such cases.

Available since scons 3.1 (experimental).

AUTHORS

       Originally: Steven Knight knight@baldmt.com and Anthony Roach aroach@electriceyeball.com.

       Since 2010: The SCons Development Team scons-dev@scons.org.

AUTHORS

       Steven Knight
           Author.

       Steven Knight and the SCons Development Team

COPYRIGHT

       Copyright © 2004 - 2020 The SCons Foundation

NOTES

        1. LLVM specification
           https://clang.llvm.org/docs/JSONCompilationDatabase.html

        2. on GitHub
           https://github.com/SCons/scons

NAME

SYNOPSIS

DESCRIPTION

OPTIONS

CONFIGURATION FILE REFERENCE

EXTENDING SCONS

SYSTEM-SPECIFIC BEHAVIOR

ENVIRONMENT

SEE ALSO

AUTHORS

AUTHORS

COPYRIGHT

NOTES