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    perl Build.PL --prefix /tmp/foo
    perl Makefile.PL PREFIX=/tmp/foo

Because of the complex nature of the prefixification logic, the
behavior of PREFIX in C<MakeMaker> has changed subtly over time.
Module::Build's --prefix logic is equivalent to the PREFIX logic found
in C<ExtUtils::MakeMaker> 6.30.

The maintainers of C<MakeMaker> do understand the troubles with the
PREFIX mechanism, and added INSTALL_BASE support in version 6.31 of
C<MakeMaker>, which was released in 2006.

If you don't need to retain compatibility with old versions (pre-6.31) of C<ExtUtils::MakeMaker> or
are starting a fresh Perl installation we recommend you use
C<install_base> instead (and C<INSTALL_BASE> in C<ExtUtils::MakeMaker>).
See L<Module::Build::Cookbook/Installing in the same location as
ExtUtils::MakeMaker> for further information.


=back


=head1 MOTIVATIONS

There are several reasons I wanted to start over, and not just fix
what I didn't like about C<MakeMaker>:

=over 4

=item *

I don't like the core idea of C<MakeMaker>, namely that C<make> should be
involved in the build process.  Here are my reasons:

=over 4

=item +

When a person is installing a Perl module, what can you assume about
their environment?  Can you assume they have C<make>?  No, but you can
assume they have some version of Perl.

=item +

When a person is writing a Perl module for intended distribution, can
you assume that they know how to build a Makefile, so they can
customize their build process?  No, but you can assume they know Perl,
and could customize that way.

=back

For years, these things have been a barrier to people getting the
build/install process to do what they want.

=item *

There are several architectural decisions in C<MakeMaker> that make it
very difficult to customize its behavior.  For instance, when using
C<MakeMaker> you do C<use ExtUtils::MakeMaker>, but the object created in
C<WriteMakefile()> is actually blessed into a package name that's
created on the fly, so you can't simply subclass
C<ExtUtils::MakeMaker>.  There is a workaround C<MY> package that lets
you override certain C<MakeMaker> methods, but only certain explicitly
preselected (by C<MakeMaker>) methods can be overridden.  Also, the method
of customization is very crude: you have to modify a string containing
the Makefile text for the particular target.  Since these strings
aren't documented, and I<can't> be documented (they take on different
values depending on the platform, version of perl, version of
C<MakeMaker>, etc.), you have no guarantee that your modifications will
work on someone else's machine or after an upgrade of C<MakeMaker> or
perl.

=item *

It is risky to make major changes to C<MakeMaker>, since it does so many
things, is so important, and generally works.  C<Module::Build> is an
entirely separate package so that I can work on it all I want, without
worrying about backward compatibility with C<MakeMaker>.

=item *

Finally, Perl is said to be a language for system administration.
Could it really be the case that Perl isn't up to the task of building
and installing software?  Even if that software is a bunch of
C<.pm> files that just need to be copied from one place to
another?  My sense was that we could design a system to accomplish
this in a flexible, extensible, and friendly manner.  Or die trying.

=back


=head1 TO DO

The current method of relying on time stamps to determine whether a
derived file is out of date isn't likely to scale well, since it
requires tracing all dependencies backward, it runs into problems on
NFS, and it's just generally flimsy.  It would be better to use an MD5
signature or the like, if available.  See C<cons> for an example.

 - append to perllocal.pod
 - add a 'plugin' functionality


=head1 AUTHOR

Ken Williams <kwilliams@cpan.org>

Development questions, bug reports, and patches should be sent to the
Module-Build mailing list at <module-build@perl.org>.

Bug reports are also welcome at
<http://rt.cpan.org/NoAuth/Bugs.html?Dist=Module-Build>.

The latest development version is available from the Git
repository at <https://github.com/Perl-Toolchain-Gang/Module-Build>


=head1 COPYRIGHT

Copyright (c) 2001-2006 Ken Williams.  All rights reserved.