NAME

       makepp -- Compatible but improved replacement for make

SYNOPSIS

       makepp [ -e ] [ -C dir ] [ -f makefile] [ -F makefile_or_dir ]
           [ -j n] [ -k ] [ -m method ] [ --noremake-makefiles ]
           [ --nowarn ] [ -q ] [ -R dir] [ --traditional-recursive-make ]
           [ -v ] [ --version ] [ VAR=value ... ] [ target ... ]

       mpp [-options] [ VAR=value ... ] [ target ... ]

DESCRIPTION

       Makepp, a build program which has a number of features that allow for reliable builds and simpler build
       files, is a drop-in replacement for GNU make. It supports almost all of the syntax that GNU make
       supports, and can be used with makefiles produced by utilities such as automake. It is called makepp (or
       make++) because it was designed with special support for C++, which has since been extended to other
       languages like Swig or embedded SQL. Also its relationship to make is analogous to C++'s relationship to
       C: it is almost 100% backward compatible but adds a number of new features and much better ways to write
       makefiles.

       Makepp passes an extensive test-suite, and is used in several big projects.  If you have any issues with
       the latest CVS version, holler, and we'll try to fix it quickly.  Makepp runs with any version of Perl
       since 5.8.

       The following manual pages contain further information on how to use makepp:

       Tutorial
           How to write a makefile.  This is mostly intended for someone with little or no experience using any
           implementation of make.

       Compilation Tutorial
           What the Unix compilation commands do.

       Release Notes
           What changed with each release.

       Incompatibilities
           What works differently between GNU make and makepp.

       Speedup
           Various tips for making makepp go much faster.

       Perl Performance
           Various tips for making Perl programming (within your makefiles and elsewhere) go faster.

       Cookbook
           Quick answers to "How do I ...?" or "What's the best way to ...?"

       FAQ Quick answers to questions people have stumbled upon.

       Build Algorithm
           How makepp's build algorithm differs in fundamental ways from traditional make.

       Build Cache
           A build cache is a directory that stores the results of prior builds in case they are needed again in
           the same directory, or in a separate build in a different directory.

       Build Check Methods
           How makepp decides when to build.

       Builtin Commands
           Powerful, efficient commands available everwhere makepp 2.0 or newer is.

       Builtin Rules
           For very simple programs, you may not need a makefile at all!  These are the builtin rules that
           makepp knows about.

       Compatibility
           Where and and with what version of Perl makepp works.

       Extending
           How you can add functions to makepp by writing your own Perl code.

       Functions
           Functions for text manipulation and various other purposes.

       Repositories
           Repositories are a technique that simplifies both variant builds and keeping a central set of
           sources.

       Rules
           Specifying rules to build files.

       Sandboxes
           Using sandboxes to partition the build.

       Scanning
           How makepp scans for dependencies like include files.

       Signatures
           How makepp decides when files have changed.

       Statements
           Additional directives to control makepp.

       Variables
           Using variables to simplify rules.

       makepp, mpp
           Command line syntax of the main utility.

       makeppclean, mppc
           An efficient stand-alone cleanup script to remove files generated by makepp.

       makeppgraph, mppg
           A stand-alone utility to graphically analyze dependencies and the reasons for a rebuild.

       makeppinfo, mppi
           A stand-alone utility to readably dump the build info makepp remembers about each file.

       makepplog, mppl
           A stand-alone utility to analyze dependencies and the reasons for a rebuild.

       makeppreplay, mppr
           A stand-alone utility to repeat things makepp has done, but much faster.

       Index
           All keywords, functions and operators in makepp.

   Features
       Automatic scanning for include files
           Makepp scans automatically for include files.  This obviates the need for tools like makedepend.
           Makepp's scanner works even if the included files don't exist yet but have to be built.  (This is
           true no matter where on the include path they come from, unlike programs that depend on gcc's
           "-MM -MG" option.)  Makepp has a flexible system for doing this which is based on scanning the build
           command; you can adapt it for other languages or build commands by writing a Perl subroutine.

       Better system for hierarchical builds
           Makepp has a better system for handling builds involving multiple directories and multiple makefiles.
           The traditional technique is to have make invoke itself recursively in each directory.  Depending on
           how complicated the interdependencies are, several recursive passes are sometimes needed.  This makes
           the makefiles very complicated if they guarantee a correct build.  The real problem is that unless
           dependencies are trivial (e.g., just one library file), it is almost impossible to express accurately
           dependencies of targets in one makefile in terms of targets from the other makefile.  Unix make isn't
           smart enough to realize that a target in one makefile depends on a file that is a target in a lower-
           level makefile; it can't take build commands from the lower-level makefile while it is trying to
           build the target in the upper-level makefile.  So the usual solution is to build everything that can
           be built with the lower-level makefiles, hoping that that's adequate to build everything that's
           needed for the upper-level makefile.

           Makepp loads all the needed makefiles in at once, so it has no problem dealing with situations where
           a file from one makefile depends on a file produced by a different makefile.  Makepp cd's
           automatically to the directory containing the makefile before executing a command from a makefile, so
           each makefile may be written independently without knowledge of the top-level build directory.  But
           if access to the root of your build tree is important (e.g. because that's where your include
           directory resides), you can name the makefile in that directory specially.  Then makepp gives you the
           path to that directory in a variable.

           Makepp also can figure out where all the makefiles for the entire project are without being told, if
           each makefile is in the same directory as the files it is supposed to produce.  This can also
           simplify makefiles a great deal.

           For more details on building with multiple directories, see "Tips for multiple directories" in
           makepp_cookbook.

       Reliable wildcards
           Makefiles can use wildcards reliably, because wild cards match either files that exist, or files that
           do not yet exist but makepp knows how to build.  So even for a program with dozens of modules, your
           entire makefile could simply read something like this:

               CXX = g++
               CXXFLAGS = -g

               %.o : %.c
                   $(CXX) $(CXXFLAGS) -c $(input) -o $(output)

               my_program: *.o
                   $(CXX) $(inputs) -o $(output)

           and this will work even if none of the ".o" files have been built yet.

       Reliable builds: remembers build command
           Makepp keeps track of the build commands, so that if compilation options change, files are
           automatically rebuilt.  This is important to guarantee correct builds.  (This idea was taken from Bob
           Sidebothem's "cons" utility, which was described in the Perl Journal in 1998 and is available from
           CPAN.)

           To illustrate why this is important, consider the following structure definition:

               class ABC {
                 int x;
               #ifndef SPECIAL_OPTION
                 int y;
               #endif
                 int z;
               };

           Now suppose you decide to turn on the "SPECIAL_OPTION" option by adding "-DSPECIAL_OPTION" to the
           command line.  A recompilation of everything is needed, but a traditional Unix make will not detect
           this, and will only recompile source files which have actually changed.  As a result, some of your
           modules will be compiled with -DSPECIAL_OPTION, and others won't.  After a very frustrating debugging
           session, you will discover that all that needs to be done is to rebuild everything.  Then you will
           curse make and hopefully switch to an improved implementation of it, like makepp.  At least, that's
           what I did.

           As another example, suppose that you are working on a project which is pretty well debugged, so it's
           usually compiled with "-O2".  Now you run into a bug which you need to look at in the debugger.  Code
           compiled with optimization is difficult to examine in the debugger, so you want to recompile your
           code so that you can look at it.  If your makefile is set up to store the compiler options in the
           usual variables, you can just do this:

               makepp CFLAGS=-g CXXFLAGS=-g

           and makepp will know that the command line has changed for all the modules.  Then when you've found
           your bug, just type

               makepp

           and it will be recompiled with optimization.  You don't need to type "make clean" when you change
           build options.

           Some makefiles (e.g., those for the Linux kernel) go to incredible lengths to force recompilation
           when the compile command changes.  With makepp, it's taken care of automatically--you don't have to
           do anything.

       Reliable builds: exact matching of signature
           By default, makepp doesn't merely ensure that all targets are newer than all dependencies; if you
           replace a dependency with an older file, makepp knows that it has to rebuild the target, simply
           because the input file has changed.  This is another important feature to guarantee correct builds
           which was taken from the "cons" utility.

       Smart signature calculations
           Some modifications to source files do not actually require a rebuild.  For example, if you just
           change a comment line, or if you reindent some code, there is no particular reason to force a
           compilation.  For C/C++ compilation, makepp determines whether a file needs recompilation by
           computing a cryptographic checksum of the file's contents, ignoring comments and whitespace, instead
           of looking at the file time.

           This is particularly useful if you have include files that are generated by files that change, and
           yet the generated include files themselves seldom change.  Suppose you have a complicated yacc
           grammar in your program, with a build rule like this:

               y.tab.c y.tab.h: parser.y
                   yacc -d parser.y

           Ordinarily, every time you make even a tiny change to "parser.y", every file that depends on
           "y.tab.h" must be rebuilt since the file time of "y.tab.h" has changed.  However, most changes to
           "parser.y" won't actually change the contents of "y.tab.h" (except possibly a comment), so all that
           recompilation is unnecessary.

       Repositories
           Makepp can automatically incorporate files from a different directory tree (the "repository") into
           the current build tree as needed.  (This idea was also taken from the "cons" program.)  This has
           several interesting uses:

           Variant builds
               Suppose you have been compiling your program with optimization on and debugging off.  Now a bug
               crops up and you have to recompile everything with debugging enabled.  Once you find the bug,
               however, you're going to turn debugging off and optimization back on, and with most make programs
               you would have to recompile all the sources again, even the ones that did not change.  The
               procedure would look like this:

                   % makepp CFLAGS=-O2                 # Compile everything.
                   # oops, bug discovered here
                   % makepp CFLAGS=-g                  # Recompiles everything again.
                   gdb my_program
                   # ... find the bug
                   % makepp CFLAGS=-O2                 # Recompiles everything a third time.

               With makepp, you can simply cd to an empty directory, and specify your original directory as a
               repository.  This will create new object files in the empty directory, while leaving your old
               object files intact.  Now you can find the bug in the directory compiled with debug, fix it in
               your original sources, and then go back to your original directory.  Now only the few files that
               you changed actually need to be recompiled.

               The entire procedure would look like this:

                   % makepp CFLAGS=-O2                 # Compile everything.
                   # oops, bug discovered here
                   % mkdir debugging
                   % cd debugging
                   % makepp -R .. CFLAGS=-g            # Compile with debugging enabled, but
                                                       # put objects in debugging subdir.
                   % gdb my_program
                   # ... find the bug
                   % cd ..                             # Back to original directory.
                   % makepp CFLAGS=-O2                 # Recompiles only those files
                                                       # that you changed.

               This can be a tremendous savings in time if there are many modules.

           Development team with common sources
               Suppose you have a team of developers working on a standard set of sources.  Each developer is
               making independent changes, but doesn't need to have a copy of the whole source tree.  Using
               makepp's repositories, you can have each developer have copies only of the files he has changed.
               Makepp will automatically and temporarily create symbolic links for the other files that have not
               been changed to the corresponding files in the repository.  It can even do this for object files
               which exist in the repository and do not need to be recompiled in the developer's individual
               directory.

           Guarantee correct rules
               If your rules do somthing which you didn't tell makepp about, the repository mechanism will not
               know to fetch those things.  So something that builds normally but fails from a repository tells
               you to fix your rules.

       Automatic inference of needed ".o" files
           Makepp can often infer exactly which objects are actually necessary without being explicitly told.
           If you use this feature, then if one of your source file includes "xx.h", and there is a file called
           "xx.o" that makepp knows how to make, then makepp adds "xx.o" to the link command line.  I don't use
           non-shared libraries now in many places where I used to, because makepp can automatically pick out
           the modules I need.

       Correct handling of aliases for directories
           Makepp won't be confused by soft links to a directory or by different relative filenames that refer
           to the same file.  All directory paths to a file are recognized, including foo, ./foo, ../src/foo,
           /auto_mnt/somedisk/bob/src/foo, and /users/bob/src/foo.

       Filenames with special characters
           Makepp can support filenames with colons or spaces or other special characters that cause trouble for
           the traditional make.  Just surround the filename with quotes.  (See "Special characters" in
           makepp_rules for details.)

       Extensible textual substutition functions
           Makepp can use arbitrary Perl subroutines for textual substitution in the makefile.  If you know
           Perl, you are not constrained at all by the set of makepp's builtin textual manipulation functions.

           You can also simply write Perl code in your makefile.  You can manipulate Make variables with the
           full power of the entire Perl language.  See makepp_variables for details.

       Logging of build decisions
           By default, makepp makes a log-file viewable with makepplog, mppl that contains a description of
           every file that it tried to build, what rule was used to build it, what it depended on, and (if the
           file was rebuilt) why.  This can be extremely useful for debugging a makefile--if you're wondering
           why makepp decided to rebuild a file, or why it didn't, you can just look in the log file where it
           explains the decisions.

       Improved support for parallel builds
           Makepp supports parallel compilations, but (unlike other make implementations) it won't mix output
           from separate processes which are running simultaneously.

       Synonyms for cryptic variables
           Makepp supports easier-to-remember synonyms for the cryptic make variables $@, $^, and $<.  See
           makepp_variables for details.