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perlsource (1)


perlsource - A guide to the Perl source tree


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Perl Programmers Reference Guide                                 PERLSOURCE(1)

       perlsource - A guide to the Perl source tree

       This document describes the layout of the Perl source tree. If you're
       hacking on the Perl core, this will help you find what you're looking

       The Perl source tree is big. Here's some of the thing you'll find in

   C code
       The C source code and header files mostly live in the root of the
       source tree. There are a few platform-specific directories which
       contain C code. In addition, some of the modules shipped with Perl
       include C or XS code.

       See perlinterp for more details on the files that make up the Perl
       interpreter, as well as details on how it works.

   Core modules
       Modules shipped as part of the Perl core live in four subdirectories.
       Two of these directories contain modules that live in the core, and two
       contain modules that can also be released separately on CPAN. Modules
       which can be released on cpan are known as "dual-life" modules.

       o   lib/

           This directory contains pure-Perl modules which are only released
           as part of the core. This directory contains all of the modules and
           their tests, unlike other core modules.

       o   ext/

           Like lib/, this directory contains modules which are only released
           as part of the core.  Unlike lib/, however, a module under ext/
           generally has a CPAN-style directory- and file-layout and its own
           Makefile.PL.  There is no expectation that a module under ext/ will
           work with earlier versions of Perl 5.  Hence, such a module may
           take full advantage of syntactical and other improvements in Perl 5

       o   dist/

           This directory is for dual-life modules where the blead source is
           canonical. Note that some modules in this directory may not yet
           have been released separately on CPAN.  Modules under dist/ should
           make an effort to work with earlier versions of Perl 5.

       o   cpan/

           This directory contains dual-life modules where the CPAN module is
           canonical. Do not patch these modules directly! Changes to these
           modules should be submitted to the maintainer of the CPAN module.
           Once those changes are applied and released, the new version of the
           module will be incorporated into the core.

       For some dual-life modules, it has not yet been determined if the CPAN
       version or the blead source is canonical. Until that is done, those
       modules should be in cpan/.

       The Perl core has an extensive test suite. If you add new tests (or new
       modules with tests), you may need to update the t/TEST file so that the
       tests are run.

       o   Module tests

           Tests for core modules in the lib/ directory are right next to the
           module itself. For example, we have lib/strict.pm and lib/strict.t.

           Tests for modules in ext/ and the dual-life modules are in t/
           subdirectories for each module, like a standard CPAN distribution.

       o   t/base/

           Tests for the absolute basic functionality of Perl. This includes
           "if", basic file reads and writes, simple regexes, etc. These are
           run first in the test suite and if any of them fail, something is
           really broken.

       o   t/cmd/

           Tests for basic control structures, "if"/"else", "while",
           subroutines, etc.

       o   t/comp/

           Tests for basic issues of how Perl parses and compiles itself.

       o   t/io/

           Tests for built-in IO functions, including command line arguments.

       o   t/mro/

           Tests for perl's method resolution order implementations (see mro).

       o   t/op/

           Tests for perl's built in functions that don't fit into any of the
           other directories.

       o   t/opbasic/

           Tests for perl's built in functions which, like those in t/op/, do
           not fit into any of the other directories, but which, in addition,
           cannot use t/test.pl,as that program depends on functionality which
           the test file itself is testing.

       o   t/re/

           Tests for regex related functions or behaviour. (These used to live
           in t/op).

       o   t/run/

           Tests for features of how perl actually runs, including exit codes
           and handling of PERL* environment variables.

       o   t/uni/

           Tests for the core support of Unicode.

       o   t/win32/

           Windows-specific tests.

       o   t/porting/

           Tests the state of the source tree for various common errors. For
           example, it tests that everyone who is listed in the git log has a
           corresponding entry in the AUTHORS file.

       o   t/lib/

           The old home for the module tests, you shouldn't put anything new
           in here. There are still some bits and pieces hanging around in
           here that need to be moved. Perhaps you could move them?  Thanks!

       All of the core documentation intended for end users lives in pod/.
       Individual modules in lib/, ext/, dist/, and cpan/ usually have their
       own documentation, either in the Module.pm file or an accompanying
       Module.pod file.

       Finally, documentation intended for core Perl developers lives in the
       Porting/ directory.

   Hacking tools and documentation
       The Porting directory contains a grab bag of code and documentation
       intended to help porters work on Perl. Some of the highlights include:

       o   check*

           These are scripts which will check the source things like ANSI C
           violations, POD encoding issues, etc.

       o   Maintainers, Maintainers.pl, and Maintainers.pm

           These files contain information on who maintains which modules. Run
           "perl Porting/Maintainers -M Module::Name" to find out more
           information about a dual-life module.

       o   podtidy

           Tidies a pod file. It's a good idea to run this on a pod file
           you've patched.

   Build system
       The Perl build system on *nix-like systems starts with the Configure
       script in the root directory.

       Platform-specific pieces of the build system also live in platform-
       specific directories like win32/, vms/, etc.  Windows and VMS have
       their own Configure-like scripts, in their respective directories.

       The Configure script (or a platform-specific similar script) is
       ultimately responsible for generating a Makefile from Makefile.SH.

       The build system that Perl uses is called metaconfig. This system is
       maintained separately from the Perl core, and knows about the platform-
       specific Configure-like scripts, as well as Configure itself.

       The metaconfig system has its own git repository. Please see its README
       file in <https://github.com/Perl/metaconfig> for more details.

       The Cross directory contains various files related to cross-compiling
       Perl. See Cross/README for more details.

       This file lists everyone who's contributed to Perl. If you submit a
       patch, you should add your name to this file as part of the patch.

       The MANIFEST file in the root of the source tree contains a list of
       every file in the Perl core, as well as a brief description of each

       You can get an overview of all the files with this command:

         % perl -lne 'print if /^[^\/]+\.[ch]\s+/' MANIFEST

       See attributes(7) for descriptions of the following attributes:

       |Availability   | runtime/perl-532      |
       |Stability      | Pass-through volatile |

       Source code for open source software components in Oracle Solaris can
       be found at https://www.oracle.com/downloads/opensource/solaris-source-

       This software was built from source available at
       https://github.com/oracle/solaris-userland.  The original community
       source was downloaded from

       Further information about this software can be found on the open source
       community website at https://www.perl.org/.

perl v5.32.0                      2020-06-14                     PERLSOURCE(1)