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Man Pages
Module::Path(3) User Contributed Perl Documentation Module::Path(3)

Module::Path - get the full path to a locally installed module 

 use Module::Path 'module_path';
 
 $path = module_path('Test::More');
 if (defined($path)) {
   print "Test::More found at $path\n";
 } else {
   print "Danger Will Robinson!\n";
 }

This module provides a single function, "module_path()", which takes a module name and finds the first directory in your @INC path where the module is installed locally. It returns the full path to that file, resolving any symlinks. It is portable and only depends on core modules.

It works by looking in all the directories in @INC for an appropriately named file:

  • Foo::Bar becomes "Foo/Bar.pm", using the correct directory path separator for your operating system.
  • Iterate over @INC, ignoring any references (see "require" in "perlfunc" if you're surprised to hear that you might find references in @INC).
  • For each directory in @INC, append the partial path ("Foo/Bar.pm"), again using the correct directory path separator. If the resulting file exists, return this path.
  • If a directory in @INC is a symlink, then we resolve the path, and return a path containing the linked-to directory.
  • If no file was found, return "undef".

I wrote this module because I couldn't find an alternative which dealt with the points listed above, and didn't pull in what seemed like too many dependencies to me.

The distribution for "Module::Path" includes the "mpath" script, which lets you get the path for a module from the command-line:

 % mpath Module::Path

The "module_path()" function will also cope if the module name includes ".pm"; this means you can pass a partial path, such as used as the keys in %INC:

  module_path('Test/More.pm') eq $INC{'Test/More.pm'}

The above is the basis for one of the tests.

Obviously this only works where the module you're after has its own ".pm" file. If a file defines multiple packages, this won't work.

This also won't find any modules that are being loaded in some special way, for example using a code reference in @INC, as described in "require" in "perlfunc".

There are a number of other modules on CPAN which provide the same or similar functionality: App::whichpm, Class::Inspector, Module::Data, Module::Filename, Module::Finder, Module::Info, Module::Locate, Module::Mapper, Module::Metadata, Module::Runtime, Module::Util, and Path::ScanINC.

I've written a review of all such modules that I'm aware of:

<http://neilb.org/reviews/module-path.html>

Module::Path was written to be fast, portable, and have a low number of core-only runtime dependencies. It you only want to look up the path to a module, it's a good choice.

If you want more information, such as the module's version, what functions are provided, etc, then start by looking at Module::Info, Module::Metadata, and Class::Inspector.

The following scripts can also give you the path: perldoc, whichpm <https://www.metacpan.org/module/whichpm>.

<https://github.com/neilbowers/Module-Path>

Neil Bowers <neilb@cpan.org>

This software is copyright (c) 2012 by Neil Bowers <neilb@cpan.org>.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.

2015-03-16 perl v5.32.1
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