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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 MakeMaker.

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

           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 systems.

           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

                   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
           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 installation.

           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

           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:

           o       pure perl.  no make, no shell commands

           o       easier to customize

           o       cleaner internals

           o       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 features.

   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-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 so:

               ($VERSION) = q$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 properly.

               $VERSION = sprintf "%d.%03d", q$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

       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

           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'

       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 Makefile:

                     # 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 Glib::CodeGen.


   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

       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

   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


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

       o make a pull request on the MakeMaker github repository

       o raise a issue on the MakeMaker github repository

       o file an RT ticket

       o email


       The denizens of



perl v5.28.1                      2018-11-01     ExtUtils::MakeMaker::FAQ(3pm)

perl 5.28.1 - Generated Sat Jan 12 08:24:53 CST 2019
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