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       ExtUtils::MakeMaker::FAQ - Frequently Asked Questions About MakeMaker


       FAQs, tricks and tips for "ExtUtils::MakeMaker".

   Module Installation
       How do I install a module into my home directory?
           If you're not the Perl administrator you probably don't have permission to install a
           module to its default location. Ways of handling this with a lot less manual effort on
           your part are perlbrew and local::lib.

           Otherwise, you can install it for your own use into your home directory like so:

               # Non-unix folks, replace ~ with /path/to/your/home/dir
               perl Makefile.PL INSTALL_BASE=~

           This will put modules into ~/lib/perl5, man pages into ~/man and programs into ~/bin.

           To ensure your Perl programs can see these newly installed modules, set your
           "PERL5LIB" environment variable to ~/lib/perl5 or tell each of your programs to look
           in that directory with the following:

               use lib "$ENV{HOME}/lib/perl5";

           or if $ENV{HOME} isn't set and you don't want to set it for some reason, do it the
           long way.

               use lib "/path/to/your/home/dir/lib/perl5";

       How do I get MakeMaker and Module::Build to install to the same place?
           Module::Build, as of 0.28, supports two ways to install to the same location as

           We highly recommend the install_base method, its the simplest and most closely
           approximates the expected behavior of an installation prefix.

           1) Use INSTALL_BASE / "--install_base"

           MakeMaker (as of 6.31) and Module::Build (as of 0.28) both can install to the same
           locations using the "install_base" concept.  See "INSTALL_BASE" in ExtUtils::MakeMaker
           for details.  To get MM and MB to install to the same location simply set INSTALL_BASE
           in MM and "--install_base" in MB to the same location.

               perl Makefile.PL INSTALL_BASE=/whatever
               perl Build.PL    --install_base /whatever

           This works most like other language's behavior when you specify a prefix.  We
           recommend this method.

           2) Use PREFIX / "--prefix"

           Module::Build 0.28 added support for "--prefix" which works like MakeMaker's PREFIX.

               perl Makefile.PL PREFIX=/whatever
               perl Build.PL    --prefix /whatever

           We highly discourage this method.  It should only be used if you know what you're
           doing and specifically need the PREFIX behavior.  The PREFIX algorithm is complicated
           and focused on matching the system installation.

       How do I keep from installing man pages?
           Recent versions of MakeMaker will only install man pages on Unix-like operating

           For an individual module:

                   perl Makefile.PL INSTALLMAN1DIR=none INSTALLMAN3DIR=none

           If you want to suppress man page installation for all modules you have to reconfigure
           Perl and tell it 'none' when it asks where to install man pages.

       How do I use a module without installing it?
           Two ways.  One is to build the module normally...

                   perl Makefile.PL
                   make test

           ...and then use blib to point Perl at the built but uninstalled module:

                   perl -Mblib
                   perl -Mblib -e '...'

           The other is to install the module in a temporary location.

                   perl Makefile.PL INSTALL_BASE=~/tmp
                   make test
                   make install

           And then set PERL5LIB to ~/tmp/lib/perl5.  This works well when you have multiple
           modules to work with.  It also ensures that the module goes through its full
           installation process which may modify it.  Again, local::lib may assist you here.

       How can I organize tests into subdirectories and have them run?
           Let's take the following test directory structure:


           Now, inside of the "WriteMakeFile()" function in your Makefile.PL, specify where your
           tests are located with the "test" directive:

               test => {TESTS => 't/*.t t/*/*.t t/*/*/*.t'}

           The first entry in the string will run all tests in the top-level t/ directory. The
           second will run all test files located in any subdirectory under t/. The third, runs
           all test files within any subdirectory within any other subdirectory located under t/.

           Note that you do not have to use wildcards. You can specify explicitly which
           subdirectories to run tests in:

               test => {TESTS => 't/*.t t/foo/*.t t/bar/baz/*.t'}

       PREFIX vs INSTALL_BASE from Module::Build::Cookbook
           The behavior of PREFIX is complicated and depends closely on how your Perl is
           configured. The resulting installation locations will vary from machine to machine and
           even different installations of Perl on the same machine.  Because of this, its
           difficult to document where prefix will place your modules.

           In contrast, INSTALL_BASE has predictable, easy to explain installation locations.
           Now that Module::Build and MakeMaker both have INSTALL_BASE there is little reason to
           use PREFIX other than to preserve your existing installation locations. If you are
           starting a fresh Perl installation we encourage you to use INSTALL_BASE. If you have
           an existing installation installed via PREFIX, consider moving it to an installation
           structure matching INSTALL_BASE and using that instead.

       Generating *.pm files with substitutions eg of $VERSION
           If you want to configure your module files for local conditions, or to automatically
           insert a version number, you can use EUMM's "PL_FILES" capability, where it will
           automatically run each *.PL it finds to generate its basename. For instance:

               # Makefile.PL:
               require '';
               my $version = get_version();
               my @pms = qw(;
                 NAME => 'Foo',
                 VERSION => $version,
                 PM => { map { ($_ => "\$(INST_LIB)/$_") } @pms },
                 clean => { FILES => join ' ', @pms },

               sub get_version { '0.04' }
               sub process { my $v = get_version(); s/__VERSION__/$v/g; }

               require '';
               $_ = join '', <DATA>;
               my $file = shift;
               open my $fh, '>', $file or die "$file: $!";
               print $fh $_;
               package Foo;
               our $VERSION = '__VERSION__';

           You may notice that "PL_FILES" is not specified above, since the default of mapping
           each .PL file to its basename works well.

           If the generated module were architecture-specific, you could replace "$(INST_LIB)"
           above with "$(INST_ARCHLIB)", although if you locate modules under lib, that would
           involve ensuring any "lib/" in front of the module location were removed.

   Common errors and problems
       "No rule to make target `/usr/lib/perl5/CORE/config.h', needed by `Makefile'"
           Just what it says, you're missing that file.  MakeMaker uses it to determine if perl
           has been rebuilt since the Makefile was made.  It's a bit of a bug that it halts

           Some operating systems don't ship the CORE directory with their base perl install.  To
           solve the problem, you likely need to install a perl development package such as perl-
           devel (CentOS, Fedora and other Redhat systems) or perl (Ubuntu and other Debian

   Philosophy and History
       Why not just use <insert other build config tool here>?
           Why did MakeMaker reinvent the build configuration wheel?  Why not just use autoconf
           or automake or ppm or Ant or ...

           There are many reasons, but the major one is cross-platform compatibility.

           Perl is one of the most ported pieces of software ever.  It works on operating systems
           I've never even heard of (see perlport for details).  It needs a build tool that can
           work on all those platforms and with any wacky C compilers and linkers they might

           No such build tool exists.  Even make itself has wildly different dialects.  So we
           have to build our own.

       What is Module::Build and how does it relate to MakeMaker?
           Module::Build is a project by Ken Williams to supplant MakeMaker.  Its primary
           advantages are:

           ·       pure perl.  no make, no shell commands

           ·       easier to customize

           ·       cleaner internals

           ·       less cruft

           Module::Build was long the official heir apparent to MakeMaker.  The rate of both its
           development and adoption has slowed in recent years, though, and it is unclear what
           the future holds for it.  That said, Module::Build set the stage for something to
           become the heir to MakeMaker.  MakeMaker's maintainers have long said that it is a
           dead end and should be kept functioning, while being cautious about extending with new

   Module Writing
       How do I keep my $VERSION up to date without resetting it manually?
           Often you want to manually set the $VERSION in the main module distribution because
           this is the version that everybody sees on CPAN and maybe you want to customize it a
           bit.  But for all the other modules in your dist, $VERSION is really just bookkeeping
           and all that's important is it goes up every time the module is changed.  Doing this
           by hand is a pain and you often forget.

           Probably the easiest way to do this is using perl-reversion in Perl::Version:

             perl-reversion -bump

           If your version control system supports revision numbers (git doesn't easily), the
           simplest way to do it automatically is to use its revision number (you are using
           version control, right?).

           In CVS, RCS and SVN you use $Revision$ (see the documentation of your version control
           system for details).  Every time the file is checked in the $Revision$ will be
           updated, updating your $VERSION.

           SVN uses a simple integer for $Revision$ so you can adapt it for your $VERSION like

               ($VERSION) = q$Revision$ =~ /(\d+)/;

           In CVS and RCS version 1.9 is followed by 1.10.  Since CPAN compares version numbers
           numerically we use a sprintf() to convert 1.9 to 1.009 and 1.10 to 1.010 which compare

               $VERSION = sprintf "%d.%03d", q$Revision$ =~ /(\d+)\.(\d+)/g;

           If branches are involved (ie. $Revision:$) it's a little more complicated.

               # must be all on one line or MakeMaker will get confused.
               $VERSION = do { my @r = (q$Revision$ =~ /\d+/g); sprintf "%d."."%03d" x $#r, @r };

           In SVN, $Revision$ should be the same for every file in the project so they would all
           have the same $VERSION.  CVS and RCS have a different $Revision$ per file so each file
           will have a different $VERSION.  Distributed version control systems, such as SVK, may
           have a different $Revision$ based on who checks out the file, leading to a different
           $VERSION on each machine!  Finally, some distributed version control systems, such as
           darcs, have no concept of revision number at all.

       What's this META.yml thing and how did it get in my MANIFEST?!
           META.yml is a module meta-data file pioneered by Module::Build and automatically
           generated as part of the 'distdir' target (and thus 'dist').  See "Module Meta-Data"
           in ExtUtils::MakeMaker.

           To shut off its generation, pass the "NO_META" flag to "WriteMakefile()".

       How do I delete everything not in my MANIFEST?
           Some folks are surprised that "make distclean" does not delete everything not listed
           in their MANIFEST (thus making a clean distribution) but only tells them what they
           need to delete.  This is done because it is considered too dangerous.  While
           developing your module you might write a new file, not add it to the MANIFEST, then
           run a "distclean" and be sad because your new work was deleted.

           If you really want to do this, you can use "ExtUtils::Manifest::manifind()" to read
           the MANIFEST and File::Find to delete the files.  But you have to be careful.  Here's
           a script to do that.  Use at your own risk.  Have fun blowing holes in your foot.

               #!/usr/bin/perl -w

               use strict;

               use File::Spec;
               use File::Find;
               use ExtUtils::Manifest qw(maniread);

               my %manifest = map  {( $_ => 1 )}
                              grep { File::Spec->canonpath($_) }
                                   keys %{ maniread() };

               if( !keys %manifest ) {
                   print "No files found in MANIFEST.  Stopping.\n";

                     wanted   => sub {
                         my $path = File::Spec->canonpath($_);

                         return unless -f $path;
                         return if exists $manifest{ $path };

                         print "unlink $path\n";
                         unlink $path;
                     no_chdir => 1

       Which tar should I use on Windows?
           We recommend ptar from Archive::Tar not older than 1.66 with '-C' option.

       Which zip should I use on Windows for '[ndg]make zipdist'?
           We recommend InfoZIP: <>

       How do I prevent "object version X.XX does not match bootstrap parameter Y.YY" errors?
           XS code is very sensitive to the module version number and will complain if the
           version number in your Perl module doesn't match.  If you change your module's version
           # without rerunning Makefile.PL the old version number will remain in the Makefile,
           causing the XS code to be built with the wrong number.

           To avoid this, you can force the Makefile to be rebuilt whenever you change the module
           containing the version number by adding this to your WriteMakefile() arguments.

               depend => { '$(FIRST_MAKEFILE)' => '$(VERSION_FROM)' }

       How do I make two or more XS files coexist in the same directory?
           Sometimes you need to have two and more XS files in the same package.  There are three
           ways: "XSMULTI", separate directories, and bootstrapping one XS from another.

           XSMULTI Structure your modules so they are all located under lib, such that "Foo::Bar"
                   is in lib/Foo/ and lib/Foo/Bar.xs, etc. Have your top-level
                   "WriteMakefile" set the variable "XSMULTI" to a true value.

                   Er, that's it.

           Separate directories
                   Put each XS files into separate directories, each with their own Makefile.PL.
                   Make sure each of those Makefile.PLs has the correct "CFLAGS", "INC", "LIBS"
                   etc. You will need to make sure the top-level Makefile.PL refers to each of
                   these using "DIR".

                   Let's assume that we have a package "Cool::Foo", which includes "Cool::Foo"
                   and "Cool::Bar" modules each having a separate XS file. First we use the
                   following Makefile.PL:

                     use ExtUtils::MakeMaker;

                         NAME              => 'Cool::Foo',
                         VERSION_FROM      => '',
                         OBJECT              => q/$(O_FILES)/,
                         # ... other attrs ...

                   Notice the "OBJECT" attribute. MakeMaker generates the following variables in

                     # Handy lists of source code files:
                     XS_FILES= Bar.xs \
                     C_FILES = Bar.c \
                     O_FILES = Bar.o \

                   Therefore we can use the "O_FILES" variable to tell MakeMaker to use these
                   objects into the shared library.

                   That's pretty much it. Now write and Foo.xs, and Bar.xs, where
          bootstraps the shared library and simply loading

                   The only issue left is to how to bootstrap Bar.xs. This is done from Foo.xs:

                     MODULE = Cool::Foo PACKAGE = Cool::Foo

                     # boot the second XS file
                     boot_Cool__Bar(aTHX_ cv);

                   If you have more than two files, this is the place where you should boot extra
                   XS files from.

                   The following four files sum up all the details discussed so far.

                     package Cool::Foo;

                     require DynaLoader;

                     our @ISA = qw(DynaLoader);
                     our $VERSION = '0.01';
                     bootstrap Cool::Foo $VERSION;


                     package Cool::Bar;

                     use Cool::Foo; # bootstraps Bar.xs


                     #include "EXTERN.h"
                     #include "perl.h"
                     #include "XSUB.h"

                     MODULE = Cool::Foo  PACKAGE = Cool::Foo

                     # boot the second XS file
                     boot_Cool__Bar(aTHX_ cv);

                     MODULE = Cool::Foo  PACKAGE = Cool::Foo  PREFIX = cool_foo_


                         fprintf(stderr, "Cool::Foo says: Perl Rules\n");

                     #include "EXTERN.h"
                     #include "perl.h"
                     #include "XSUB.h"

                     MODULE = Cool::Bar  PACKAGE = Cool::Bar PREFIX = cool_bar_


                         fprintf(stderr, "Cool::Bar says: Perl Rules\n");

                   And of course a very basic test:

                     use Test;
                     BEGIN { plan tests => 1 };
                     use Cool::Foo;
                     use Cool::Bar;
                     ok 1;

                   This tip has been brought to you by Nick Ing-Simmons and Stas Bekman.

                   An alternative way to achieve this can be seen in Gtk2::CodeGen and


   MakeMaker object hierarchy (simplified)
       What most people need to know (superclasses on top.)

               ExtUtils::MM_{Current OS}

       The object actually used is of the class MY which allows you to override bits of MakeMaker
       inside your Makefile.PL by declaring MY::foo() methods.

   MakeMaker object hierarchy (real)
       Here's how it really works:

           ExtUtils::Liblist::Kid          ExtUtils::MM_{Current OS} (if necessary)
                 |                                          |
           ExtUtils::Liblist     ExtUtils::MakeMaker        |
                           |     |                          |
                           |     |   |-----------------------
                          |          |
               ExtUtils::MY         MM (created by ExtUtils::MM)
               |                                   |
               MY (created by ExtUtils::MY)        |
                           .                       |
                        (mixin)                    |
                           .                       |
                      PACK### (created each call to ExtUtils::MakeMaker->new)

       NOTE: Yes, this is a mess.  See
       <> for some history.

       NOTE: When ExtUtils::MM is loaded it chooses a superclass for MM from amongst the
       ExtUtils::MM_* modules based on the current operating system.

       NOTE: ExtUtils::MM_{Current OS} represents one of the ExtUtils::MM_* modules except
       ExtUtils::MM_Any chosen based on your operating system.

       NOTE: The main object used by MakeMaker is a PACK### object, *not* ExtUtils::MakeMaker.
       It is, effectively, a subclass of MY, ExtUtils::Makemaker, ExtUtils::Liblist and
       ExtUtils::MM_{Current OS}

       NOTE: The methods in MY are simply copied into PACK### rather than MY being a superclass
       of PACK###.  I don't remember the rationale.

       NOTE: ExtUtils::Liblist should be removed from the inheritance hiearchy and simply be
       called as functions.

       NOTE: Modules like File::Spec and Exporter have been omitted for clarity.

   The MM_* hierarchy
                                       MM_Win95   MM_NW5
                                            \      /
        MM_BeOS  MM_Cygwin  MM_OS2  MM_VMS  MM_Win32  MM_DOS  MM_UWIN
              \        |      |         |        /      /      /
                                  |       |
                               MM_Unix    |
                                     |    |

       NOTE: Each direct MM_Unix subclass is also an MM_Any subclass.  This is a temporary hack
       because MM_Unix overrides some MM_Any methods with Unix specific code.  It allows the non-
       Unix modules to see the original MM_Any implementations.

       NOTE: Modules like File::Spec and Exporter have been omitted for clarity.


       If you have a question you'd like to see added to the FAQ (whether or not you have the
       answer) please either:

       · make a pull request on the MakeMaker github repository

       · raise a issue on the MakeMaker github repository

       · file an RT ticket

       · email


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