Provided by: critcl_3.1.9-1_all 
NAME
critcl_introduction - Introduction To CriTcl
DESCRIPTION
Welcome to the C Runtime In Tcl, CriTcl for short, a system to build C extension packages
for Tcl on the fly, from C code embedded within Tcl scripts, for all who wish to make
their code go faster.
CriTcl started life as an experiment by Jean-Claude Wippler and was a self-contained Tcl
package to build C code into a Tcl/Tk extension on the fly. It was somewhat inspired by
Brian Ingerson's Inline for Perl, but is considerably more lightweight.
It is for the last 5% to 10% when pure Tcl, which does go a long way, is not sufficient
anymore. I.e. for
[1] when the last bits of performance are needed,
[2] access to 3rd party libraries,
[3] hiding critical pieces of your library or application, and
[4] simply needing features provided only by C.
The following sections first reference a few related documents which may or may not be of
interest to you, depending on if you are just a plain user of the system, trying to get
and build/install it, or are going deep into the internals for either edification or
modification.
This is followed by an introduction to the modes of operation supported by the system, and
its general architecture as seen by a user.
RELATED DOCUMENTS
[1] Critcl - License.
[2] Using Critcl
[3] Critcl - How To Get The Sources.
[4] Critcl - The Installer's Guide.
[5] Critcl - Application Package Reference
[6] Critcl - Package Reference
[7] Critcl - The Developer's Guide.
MODES OF OPERATION/USE
CriTcl can be used in three different modes of operation, called
[1] Compile & Run, and
[2] Generate Package
[3] Generate TEA Package
Of these three Compile & Run came first and is the default when using the package
directly. In that case the package collects the C fragments, builds them as needed, and
caches the results for quick reuse when the same code is used in the future again.
The second mode, Generate Package, was introduced to enable the creation of (prebuilt)
deliverable packages which do not depend on the existence of a build system, i.e. C
compiler, on the target machine. This was originally done through the experimental
Critbind tool, and is now handled by the CriTcl Application, also named critcl.
Newly introduced with Critcl version 3 is Generate TEA Package. This mode constructs a
directory hierarchy from the package which can later be built like a regular TEA package,
i.e. using
make all isntall
SYSTEM ARCHITECTURE
The system consists of two main layers, as seen in the figure below, plus a support layer
containing general packages the system uses during operation.
+----------------+
|Applications |
| critcl |
| critcl::app |
+----------------+
+----------------+
|Core Packages |
| critcl |
| critcl::util |
+----------------+
+----------------+
|Support Packages|
| stubs::* |
| md5, platform |
| ... |
+----------------+
[1] At the top we have an application built on top of the core packages, providing
command line access to the second and third usage modes, i.e. Generate Package and
Generate TEA Package.
critcl
critcl::app
[2] Below that is the core package providing the essential functionality of the system,
plus various utility packages which make common tasks more convenient.
critcl
critcl::util
[3] Lastly a layer of supporting packages, mostly external to critcl.
md5 For this pure-Tcl package to be fast users should get one of several
possible accelerator packages:
[1] tcllibc
[2] Trf
[3] md5c
cmdline
platform
stubs::container
stubs::reader
stubs::writer
stubs::gen
stubs::gen::init
stubs::gen::header
stubs::gen::decl
stubs::gen::macro
stubs::gen::slot
stubs::gen::lib
EXAMPLES
The sources of Critcl, should you have gotten them, contain several larger examples show-
casing various aspects of the system. These demonstration packages can all be found in the
sub-directory "examples/" of the sources.
Lots of smaller examples can be found in the document Using CriTcl, an introduction to
Critcl by way of a of examples. These focus more on specific critcl commands than the
overall picture shown by the large examples mentioned in the previous paragraph.
CHANGES FOR VERSION 2.1
[1] Fixed bug where critcl::tsources interpreted relative paths as relative to the
current working directory instead of relative to the ".critcl" file using the
command, as all other commands of this type do.
[2] Fixed internals, preventing information collected for multiple ".critcl" files to
leak between them. Notably, critcl::tk is not a global configuration option
anymore.
[3] Fixed the command critcl::license to be a null-operation in mode "compile & run",
instead of throwing an error.
[4] Fixed the critcl application's interference with the "compile & run" result cache
in -pkg mode by having it use a wholly separate (and by default transient)
directory for that mode.
[5] Fixed bug where changes to a ".critcl" file did not result in a rebuild for mode
"compile & run". All relevant API commands now ensure UUID changes.
[6] Fixed bug in the backend handling of critcl::debug where the companion c-sources of
a ".critcl" file were not compiled with debug options, although the ".critcl" file
was.
[7] Fixed bug in critcl::debug which prevented recognition of mode "all" when it was
not the first argument to the command.
[8] Fixed bug in "preload.c" preventing its compilation on non-windows platforms.
[9] Fixed long-standing bug in the handling of namespace qualifiers in the command name
argument of critcl::cproc and critcl::ccommand. It is now possible to specify a
fully qualified command name without issues.
[10] Extended/reworked critcl::tsources to be the canonical way of declaring ".tcl"
companion files even for mode "compile & run".
[11] Extended/reworked critcl::tsources to allow the use of a ".critcl" file as its own
Tcl companion file.
[12] Extended critcl::framework to internally check for OS X build target, and to ignore
the declaration if its not.
[13] Extended critcl::failed to be callable more than once in a ".critcl" file. The
first call forces the build, if it was not done already, to get the result. Further
calls return the cached result of the first call.
[14] Extended the handling of environment variable CC in the code determining the
compiler to use to deal with (i.e. remove) paths to the compiler, compiler file
extensions, and compiler options specified after the compiler itself, leaving only
the bare name of the compiler.
[15] Extended the code handling the search for preloaded libraries to print the paths it
searched, making debugging of a search failure easier.
[16] A new command critcl::tcl can be used to declare the version of Tcl minimally
needed to build and run the ".critcl" file and package. Defaults to 8.4 if not
declared. Extended critcl to have the stubs and headers for all of Tcl 8.4, 8.5,
and 8.6.
[17] A new command critcl::load forces the build and load of a ".critcl" file. This is
the official way for overriding critcl's default lazy-build-&-load-on-demand scheme
for mode "compile & run".
Note that after using critcl::load / critcl::failed in a ".critcl" file it is not
possible to use critcl commands in that file anymore. Doing so will throw an error.
[18] Extended the generation of '#line' pragmas to use info frame (if available) to
provide the C compiler with exact line numbers into the ".critcl" file for the
reporting of warnings and errors.
[19] Extended critcl::check with logging to help with debugging build-time checks of the
environment, plus an additional optional argument to provide labeling.
[20] Added a new command critcl::checklink which not only tries to check the environment
via compiling the code, but also its linkability.
[21] Added a new command critcl::msg for messaging, like command critcl::error is for
error reporting. Likewise this is a hook a user of the package is allowed to
override. The default implementation, used by mode compile & run does nothing. The
implementation for mode generate package prints the message to stdout.
Envisioned use is for the reporting of results determined by critcl::check and
critcl::checklink during building, to help with debugging when something goes wrong
with a check.
[22] Exposed the argument processing internals of critcl::proc for use by advanced
users. The new commands are
[1] critcl::argnames
[2] critcl::argcnames
[3] critcl::argcsignature
[4] critcl::argvardecls
[5] critcl::argconversion
Please see section Advanced Embedded C Code of the critcl package documentation for
details.
[23] Extended the critcl package to intercept package provide and record the file ->
package name mapping. Plus other internal changes now allow the use of namespaced
package names while still using proper path names and init function.
[24] Dropped the unused commands critcl::optimize and critcl::include.
[25] Dropped -lib mode from the critcl application.
[26] Dropped remnants of support for Tcl 8.3 and before.
CHANGES FOR VERSION 3
[1] The command critcl::platform was deprecated in version 2.1, superceded by
critcl::targetplatform, yet kept for compatibility. Now it has been removed.
[2] The command critcl::compiled was kept with in version 2.1 with semantics in
contradiction to its, for compatibility. This contradiction has been removed,
changing the visible semantics of the command to be in line with its name.
[3] The change to version 3 became necessary because of the two incompatible visible
changes above.
[4] Extended the application package with code handling a new option -tea. Specifying
this option invokes a special mode where critcl generates a TEA package, i.e. wraps
the input into a directory hierarchy and support files which provide it TEA-
lookalike buildsystem.
This new option, and -pkg, exclude each other. If both are specified the last used
option takes precedence.
The generated package directory hierarchy is mostly self-contained, but not fully.
It requires not only a working installation of Tcl, but also working installations
of the packages md5 and cmdline. Both of these are provided by the Tcllib bundle.
Not required, but recommended to have installed are any of the packages which can
accelerate md5's operation, i.e. cryptkit, tcllibc, or Trf.
[5] Extended the critcl package with a new command critcl::scan taking the path to a
".critcl" file, statically scanning it, and returning license, version, a list of
its companion files, list of imported APIs, and list of developer-specified custom
configuration options. This data is the foundation for the TEA wrapping described
above.
Note that this is a static scan. While the other build modes can (must) execute the
".critcl" file and make platform-specific decisions regarding the assembled C code,
companion files, etc. the TEA wrap mode is not in a position to make platform-
specific decisions. It has to wrap everything which might conceivably be needed
when actually building. Hence the static scan. This has however its own set of
problems, namely the inability to figure out any dynamic construction of companion
file paths, at least on its own. Thus:
[6] Extended the API used by critcl-based packages with the command critcl::owns. While
this command is ignored by the regular build modes the static scanner described
above takes its arguments as the names of companion files which have to be wrapped
into the TEA package and could not be figured by the scanner otherwise, like
because of dynamic paths to critcl::tsources, critcl::csources, getting sourced
directly, or simply being adjunct datafiles.
[7] Extended the API used by critcl-based packages with the command critcl::api for the
management of stubs tables, be it their use, and/or declaration and export.
Please see section Stubs Table Management of the critcl package documentation for
details.
[8] Extended the API used by critcl-based packages with the command critcl::userconfig
for the management of developer-specified custom configuration options, be it their
use and/or declaration.
Please see section Custom Build Configuration of the critcl package documentation
for details.
[9] Extended the API used by critcl-based packages with the commands
critcl::description, critcl::summary, critcl::subject, critcl::meta, and
critcl::buildrequirement for the declaration of TEApot meta data for/about the
package.
Please see section Package Meta Data of the critcl package documentation for
details.
CHANGES FOR VERSION 3.0.1
[1] Bugfixes all around. In detail:
[2] Fixed recording of Tcl version requirements. Keep package name and version
together, unbreaking generated meta data and generated package load command.
[3] Fixed the build scripts: When installing, or wrapping for TEA, generate any missing
directories
[4] Modified the build scripts to properly exit the application when the window of
their GUI is closed through the (X) button.
[5] Removed an 8.5-ism (open wb) which had slipped into the main build script.
[6] Modified the example build scripts to separate the output for the different
examples (and packages) by adding empty lines.
[7] stack::c example bugfix: Include API declarations for use in the companion files.
[8] Extended the documentation: Noted the need for a working installation of a C
compiler.
[9] Extended the Windows target definitions and code to handle the manifest files used
by modern MS development environments. Note that this code handles both
possibilities, environment using manifests, and (old(er)) environments without.
[10] Extended the Windows 64bit target definitions and code to auto-detect the need for
the helper library "bufferoverflowU.lib" and reconfigure the compile and link
commands appropriately. We assume that the library must be linked when present.
This should be no harm if the library is present, yet not needed. Just superfluous.
We search for the library in the paths specified by the environment variable LIB.
CHANGES FOR VERSION 3.0.2
[1] Fixed issue in compile-and-run mode where commands put into the auto_index are not
found by Tcl's [unknown] command.
[2] Fixed an array key mismatch breaking usage of client data and delete function for
procedure. Reported by Jos DeCoster, with patch.
[3] Implemented a command line option -L, an equivalent of option -I, just for library
search paths.
[4] Fixed github issues 5 and 8. Working around a missing variable ::errorInfo. It
should always be present, however there seem to be revisions of Tcl around which
violate this assumption.
CHANGES FOR VERSION 3.0.3
[1] Fixed github issues 5 and 8, for the example build.tcl scripts. Working around a
missing variable ::errorInfo. It should always be present, however there seem to be
revisions of Tcl around which violate this assumption.
CHANGES FOR VERSION 3.0.4
[1] Fixed generation of the package's initname when the incoming code is read from
stdin and has no proper path.
[2] Fixed github issue 11. Now using /LIBPATH instead of -L on Windows (libinclude
configuration setting).
[3] Extended critcl to handle -l:path format of -l options. GNU ld 2.22+ handles this
by searching for the path as is. Good when specifying static libraries, as plain -l
looks for shared libraries in preference over static. critcl handles it now, as
older GNU ld's do not understand it, nor the various vendor-specific linkers.
[4] Fixed github issue #12. Critcl now determines the version of MSVC in use and uses
it to switch between various link debug options. Simplified the handling of
bufferoverflowU.lib also, making use of the same mechanism and collapsing the two
configurations sections we had back into one.
[5] Reworked the insertion of #line pragmas into the generated C code to avoid
limitations on the line number argument imposed by various compilers, and be more
accurate.
[6] Modified argument processing. Option -libdir now also implies -L for its argument.
[7] Extended handling of option -show (critcl::showconfig) to list the path of the
configuration file the data is coming from. Good for debugging configuration
processing.
[8] Extended the build script with targets to regenerate the embedded documentation,
and diagrams, and to generate a release.
CHANGES FOR VERSION 3.0.5
[1] Fixed bug in the new code for #line pragmas triggered when specifying C code
without leading whitespace.
[2] Extended the documentation to have manpages for the license, source retrieval,
installer, and developer's guides.
CHANGES FOR VERSION 3.0.6
[1] Fixed github issue 10. The critcl application now delivers a proper exit code (1)
on build failure, instead of always indicating success (status 0).
[2] Fixed github issue 13. Handling of bufferoverflowU.lib for release builds was
inconsistent with handling for debug builds. It is now identically handled
(conditional) by both cases.
[3] Documentation cleanup, mainly in the installation guide, and the README.md shown by
github
CHANGES FOR VERSION 3.0.7
[1] Fixed the code generated by critcl::c++command. The emitted code handed a non-
static string table to Tcl_GetIndexFromObj, in violation of the contract, which
requires the table to have a fixed address. This was a memory smash waiting to
happen. Thanks to Brian Griffin for alrerting us to the general problem.
CHANGES FOR VERSION 3.1
[1] Added a new higher-level package critcl::iassoc.
This package simplifies the creation of code associating data with an interpreter
via Tcl's Tcl_(Get|Set)AssocData() APIs. The user can concentrate on his data while
all the necessary boilerplate C code to support this is generated by the package.
This package uses several of the new features which were added to the core critcl
package, see below.
[2] Added the higher-level package critcl::class.
This package simplifies the creation of C level objects with class and instance
commands. The user can write a class definition with class- and instance-variables
and -methods similar to a TclOO class, with all the necessary boilerplate C code to
support this generated by the package.
This package uses several of the new features which were added to the core critcl
package, see below.
[3] Extended the API for handling TEApot metadata. Added the command critcl::meta? to
query the stored information. Main use currently envisioned is retrieval of the
current package's name by utility commands, for use in constructed names. This
particular information is always available due to the static scan of the package
file on execution of the first critcl command.
The new packages critcl::iassoc and critcl::class (see above) are users of this
command.
[4] Extended the API with a command, critcl::name2c, exposing the process of converting
a Tcl name into base name, namespace, and C namespace. This enables higher-level
code generators to generate the same type of C identifiers as critcl itself.
The new package critcl::class (see above) is a user of this command.
[5] Extended the API with a command, critcl::source, executing critcl commands found in
a separate file in the context of the current file. This enables easier management
of larger bodies of code as it allows the user to split such up into easier to
digest smaller chunks without causing the generation of multiple packages.
[6] Related to the previous item, extended the API with commands to divert collection
of generated C code into memory. This makes it easier to use the commands for
embedded C code in higher-level code generators.
See the section Advanced: Diversions for details of the provided commands.
The new package critcl::class (see above) is a user of these facilities.
[7] Extended the API with commands helping developers with the generation of proper C
#line directives. This allows higher-level code generators to generate and insert
their own directives, ensuring that compile errors in their code are properly
attributed.
See the section Advanced: Location management for details of the provided commands.
The new packages critcl::iassoc and critcl::class (see above) are users of these
facilities.
[8] Extended the API with commands giving users the ability to define custom argument
and result types for ::critcl::cproc.
See the section Advanced: Extending cproc for details of the provided commands.
CHANGES FOR VERSION 3.1.1
[1] Bugfixes all around. In detail:
[2] Fixed the generation of wrong#args errors for critcl::cproc and derived code
(critcl::class cproc-based methods). Use NULL if there are no arguments, and take
the offset into account.
[3] Fixed the handling of package names by critcl::class. Forgot that they may contain
namespace separators. Bumped to version 1.0.1.
[4] Extended a critcl::class generated error message in instance creation for clarity.
Bumped to version 1.0.2.
CHANGES FOR VERSION 3.1.2
[1] Enhancement. In detail:
[2] Extended critcl::cproc to be able to handle optional arguments, in a limited way.
This is automatically available to critcl::class cproc-based methods as well.
[3] Bugfix in lassign emulation for Tcl 8.4. Properly set unused variables to the
empty string. Bumped version of emulation package lassign84 to 1.0.1.
CHANGES FOR VERSION 3.1.3
[1] Enhancement. In detail:
[2] Added new argument type "pstring", for "Pascal String", a counted string, i.e. a
combination of string pointer and string length.
[3] Added new methods critcl::argtypesupport and ::critcl::argsupport to define and use
additional supporting code for an argument type, here used by "pstring" above to
define the necessary structure.
[4] Semi-bugfixes in the packages critcl::class and critcl::iassoc. Pragmas for the AS
meta data scanner to ensure that the template files are made part of the package.
Versions bumped to 1.0.4 and 1.0.1 respectively.
CHANGES FOR VERSION 3.1.4
[1] Bugfix in package critcl::class. Generate a dummy field in the class structure if
the class has no class variables. Without this change the structure would be empty,
and a number of compilers are not able to handle such a type.
[2] Fixed a typo which broke the win64 configuration.
[3] Fixed issue #16, a typo in the documentation of command critcl::class.
CHANGES FOR VERSION 3.1.5
[1] Fixed issue #19. Made the regular expression extracting the MSVC version number
more general to make it work on german language systems. This may have to be
revisited in the future, for other Windows locales.
[2] Fixed issue #20. Made option -tea work on windows, at least in a unix emulation
environment like msys/mingw.
CHANGES FOR VERSION 3.1.6
[1] Fixed issue #21. While the multi-definition of the stub-table pointer variables was
ok with for all the C linkers seen so far C++ linkers did not like this at all.
Reworked the code to ensure that this set of variables is generated only once, in
the wrapper around all the pieces to assemble.
[2] Fixed issue #22, the handling of the command identifier arguments of
critcl::ccommand, critcl::cproc, and critcl::cdata. We now properly allow any Tcl
identifier and generate proper internal C identifiers from them.
As part of this the signature of command critcl::name2c changed. The command now
delivers a list of four values instead of three. The new value was added at the
end.
Further adapted the implementation of package critcl::class, a user of
critcl::name2c. This package is now at version 1.0.6 and requires critcl 3.1.6
Lastly fixed the mis-handling of option -cname in critcl::ccommand, and
critcl::cproc.
[3] Fixed issue #23.
CHANGES FOR VERSION 3.1.7
[1] Fixed issue #24. Extract and unconditionally display compiler warnings found in the
build log. Prevents users from missing warnings which, while not causing the build
to fail, may still indicate problems.
[2] New feature. Output hook. All non-messaging user output is now routed through the
command critcl::print, and users are allowed to override it when using the critcl
application-as-package.
[3] New feature, by Ashok P. Nadkarni. Platform configurations can inherit values from
configurations defined before them.
CHANGES FOR VERSION 3.1.8
[1] Fixed issue with package indices generated for Tcl 8.4. Join the list of commands
with semi-colon, not newline.
[2] Fixed issue #26 which brought up use-cases I had forgotten to consider while fixing
bug #21 (see critcl 3.1.6).
CHANGES FOR VERSION 3.1.9
[1] Fixed issue #27. Added missing platform definitions for various alternate linux and
OS X targets.
[2] Fixed issue #28. Added missing -mXX flags for linking at the linux-{32,64}-*
targets.
[3] Fixed issue #29. Replaced the use of raw "cheaders" information in the processing
of "cdefines" with the proper include directives derived from it.
[4] Fixed the issue behind rejected pull request #30 by Andrew Shadura. Dynamically
extract the stubs variable declarations from the Tcl header files and generate
matching variable definitions for use in the package code. The generated code will
now be always consistent with the headers, even when critcl's own copy of them is
replaced by system headers.
[5] Fixed issue #31. Accepted patch by Andrew Shadura, with changes (comments), for
easier integration of critcl with OS package systems, replacing critcl's copies of
Tcl headers with their own.
[6] Fixed issue #32. Merged pull request by Andrew Shadura. Various typos in
documentation and comments.
[7] Fixed issue #33. Handle files starting with a dot better.
AUTHORS
Jean Claude Wippler, Steve Landers, Andreas Kupries
BUGS, IDEAS, FEEDBACK
This document, and the package it describes, will undoubtedly contain bugs and other
problems. Please report them at https://github.com/andreas-kupries/critcl/issues. Ideas
for enhancements you may have for either package, application, and/or the documentation
are also very welcome and should be reported at https://github.com/andreas-
kupries/critcl/issues as well.
KEYWORDS
C code, Embedded C Code, code generator, compile & run, compiler, dynamic code generation,
dynamic compilation, generate package, linker, on demand compilation, on-the-fly
compilation
CATEGORY
Glueing/Embedded C code
COPYRIGHT
Copyright (c) Jean-Claude Wippler
Copyright (c) Steve Landers
Copyright (c) 2011-2013 Andreas Kupries