MAN page from Fedora 6 perl-ExtUtils-MakeMaker-6.46-1.fc6.rf.noarch.rpm


Section: User Contributed Perl Documentation (3)
Updated: 2007-12-30


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 havepermission to install a module to its default location. Then youshould 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 andprograms into ~/bin.

To ensure your Perl programs can see these newly installed modules,set your "PERL5LIB" environment variable to ~/lib/perl5 or telleach 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 somereason, 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 samelocation as MakeMaker.

1) Use INSTALL_BASE / "--install_base"

MakeMaker (as of 6.31) and Module::Build (as of 0.28) both can installto the same locations using the ``install_base'' concept. See``INSTALL_BASE'' in ExtUtils::MakeMaker for details. To get MM and MB toinstall 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

2) Use PREFIX / "--prefix"

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

    perl Makefile.PL PREFIX=/whatever    perl Build.PL    --prefix /whatever
How do I keep from installing man pages?
Recent versions of MakeMaker will only install man pages on Unix likeoperating systems.

For an individual module:

        perl Makefile.PL INSTALLMAN1DIR=none INSTALLMAN3DIR=none

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

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

        perl Makefile.PL        make        make test

...and then set the PERL5LIB environment variable to point at theblib/lib and blib/arch directories.

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

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

And then set PERL5LIB to ~/tmp/lib/perl5. This works well when youhave multiple modules to work with. It also ensures that the modulegoes through its full installation process which may modify it.

PREFIX vs INSTALL_BASE from Module::Build::Cookbook
The behavior of PREFIX is complicated and depends closely on how yourPerl is configured. The resulting installation locations will vary frommachine 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 reasonto use PREFIX other than to preserve your existing installation locations. If youare starting a fresh Perl installation we encourage you to use INSTALL_BASE. Ifyou have an existing installation installed via PREFIX, consider moving it to aninstallation structure matching INSTALL_BASE and using that instead.


Philosophy and History

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

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

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

No such build tool exists. Even make itself has wildly differentdialects. 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 is the official heir apparent to MakeMaker and weencourage people to work on M::B rather than spending time adding featuresto MakeMaker.


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 moduledistribution because this is the version that everybody sees on CPANand maybe you want to customize it a bit. But for all the othermodules in your dist, $VERSION is really just bookkeeping and all that'simportant is it goes up every time the module is changed. Doing thisby hand is a pain and you often forget.

Simplest way to do it automatically is to use your version controlsystem's revision number (you are using version control, right?).

In CVS, RCS and SVN you use $Revision$ (see the documentation of yourversion control system for details). Every time the file is checkedin 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 comparesversion numbers numerically we use a sprintf() to convert 1.9 to 1.009and 1.10 to 1.010 which compare properly.

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

If branches are involved (ie. $Revision:$) its a little morecomplicated.

    # 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 sothey would all have the same $VERSION. CVS and RCS have a different$Revision$ per file so each file will have a differnt $VERSION.Distributed version control systems, such as SVK, may have a different$Revision$ based on who checks out the file leading to a different $VERSIONon each machine! Finally, some distributed version control systems, suchas 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 andautomatically 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 surpried that "make distclean" does not deleteeverything not listed in their MANIFEST (thus making a cleandistribution) but only tells them what they need to delete. This isdone because it is considered too dangerous. While developing yourmodule you might write a new file, not add it to the MANIFEST, thenrun 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::Findto delete the files. But you have to be careful. Here's a script todo 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";        exit;    }

    find({          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         },         "."    );


How to 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 willcomplain if the version number in your Perl module doesn't match. Ifyou change your module's version # without rerunning Makefile.PL the oldversion number will remain in the Makefile causing the XS code to be builtwith the wrong number.

To avoid this, you can force the Makefile to be rebuilt whenever youchange the module containing the version number by adding this to yourWriteMakefile() 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.One way to go is to put them into separate directories, but sometimesthis is not the most suitable solution. The following technique allowsyou to put two (and more) XS files in the same directory.

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

  use ExtUtils::MakeMaker;

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

Notice the "OBJECT" attribute. MakeMaker generates the followingvariables in Makefile:

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

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

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

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

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

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

If you have more than two files, this is the place where you shouldboot 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;

  1;  -------  package Cool::Bar;

  use Cool::Foo; # bootstraps Bar.xs


  Foo.xs:  -------  #include "EXTERN.h"  #include "perl.h"  #include "XSUB.h"

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

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

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

  void  cool_foo_perl_rules()

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

  Bar.xs:  -------  #include "EXTERN.h"  #include "perl.h"  #include "XSUB.h"

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

  void  cool_bar_perl_rules()

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

And of course a very basic test:

  t/cool.t:  --------  use Test;  BEGIN { plan tests => 1 };  use Cool::Foo;  use Cool::Bar;  Cool::Foo::perl_rules();  Cool::Bar::perl_rules();  ok 1;

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



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Module Installation
Philosophy and History
Module Writing

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