CPAN::Meta::History::Meta_1_0 - Version 1.0 metadata specification for META.yml
This is a historical copy of the version 1.0 specification for META.yml
files, copyright by Ken Williams and licensed under the same terms as Perl
Modifications from the original:
This document describes version 1.0 of the META.yml specification.
- Conversion from the original HTML to POD format
- Include list of valid licenses from Module::Build 0.17 rather than linking
to the module, with minor updates to text and links to reflect versions at
the time of publication.
- Fixed some dead links to point to active resources.
The META.yml file describes important properties of contributed
Perl distributions such as the ones found on CPAN
<http://www.cpan.org>. It is typically created by tools like
Module::Build and ExtUtils::MakeMaker.
The fields in the META.yml file are meant to be helpful to
people maintaining module collections (like CPAN), for people writing
installation tools (like CPAN or CPANPLUS), or just people who want to know
some stuff about a distribution before downloading it and starting to
META.yml files are written in the YAML <http://www.yaml.org/>
format. The reasons we chose YAML instead of, say, XML or Data::Dumper are
discussed in this thread
the MakeMaker mailing list.
The first line of a META.yml file should be a valid YAML
The rest of the META.yml file is one big YAML mapping
keys are described here.
- Example: "Module-Build"
The name of the distribution. Often created by taking the
"main module" in the distribution and changing "::"
to "-". Sometimes it's completely different, however, as in
the case of the libwww-perl
- Example: 0.16
The version of the distribution to which the META.yml file
- Example: "perl"
The license under which this distribution may be used and
Must be one of the following licenses:
- The distribution may be copied and redistributed under the same terms as
perl itself (this is by far the most common licensing option for modules
on CPAN). This is a dual license, in which the user may choose between
either the GPL version 1 or the Artistic version 1 license.
- The distribution is distributed under the terms of the GNU General Public
License version 2 (<http://opensource.org/licenses/GPL-2.0>).
- The distribution is distributed under the terms of the GNU Lesser General
Public License version 2
- The distribution is licensed under the Artistic License version 1, as
specified by the Artistic file in the standard perl distribution
- The distribution is licensed under the BSD 3-Clause License
- The distribution is licensed under some other Open Source
Initiative-approved license listed at
- The distribution is licensed under a license that is not approved
by www.opensource.org <http://www.opensource.org/> but that allows
distribution without restrictions.
- The distribution may not be redistributed without special permission from
the author and/or copyright holder.
- Example: "module"
What kind of stuff is contained in this distribution. Most
things on CPAN are "module"s (which
can also mean a collection of modules), but some things are
A YAML mapping
indicating the Perl modules this distribution requires for proper
operation. The keys are the module names, and the values are version
specifications as described in the documentation for Module::Build's
Note: the exact nature of the fancy specifications like
">= 1.2, != 1.5, < 2.0" is subject
to change. Advance notice will be given here. The simple
specifications like "1.2" will not change
A YAML mapping
indicating the Perl modules this distribution recommends for enhanced
A YAML mapping
indicating the Perl modules required for building and/or testing of this
distribution. These dependencies are not required after the module is
A YAML mapping
indicating the Perl modules that cannot be installed while this
distribution is installed. This is a pretty uncommon situation.
- Example: 0
A boolean flag indicating whether a Build.PL or
Makefile.PL (or similar) must be executed, or whether this module
can be built, tested and installed solely from consulting its metadata
file. The main reason to set this to a true value if that your module
performs some dynamic configuration (asking questions, sensing the
environment, etc.) as part of its build/install process.
Currently Module::Build doesn't actually do anything with this
flag - it's probably going to be up to higher-level tools like CPAN.pm
to do something useful with it. It can potentially bring lots of
security, packaging, and convenience improvements.
- Example: "Module::Build version 0.16"
Indicates the tool that was used to create this
META.yml file. It's good form to include both the name of the
tool and its version, but this field is essentially opaque, at least for
- An RDF vocabulary to describe software projects.
- March 14, 2003 (Pi day) - created version 1.0 of this
- May 8, 2003 - added the "dynamic_config" field, which was
missing from the initial version.