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Alien::Base::ModuleBuild - A Module::Build subclass for building Alien:: modules and their libraries


version 1.17


In your Build.PL:

 use Alien::Base::ModuleBuild;
 my $builder = Alien::Base::ModuleBuild->new(
   module_name => 'Alien::MyLibrary',
   configure_requires => {
     'Alien::Base::ModuleBuild' => '0.005',
     'Module::Build' => '0.28'
   requires => {
     'Alien::Base' => '0.005',
   alien_name => 'mylibrary', # the pkg-config name if you want
                              # to use pkg-config to discover
                              # system version of the mylibrary
   alien_repository => {
     protocol => 'https',
     host     => '',
     location => '/path/to/tarballs',
     pattern  => qr{^mylibrary-([0-9\.]+)\.tar\.gz$},
   # this is the default:
   alien_build_commands => [
     "%c --prefix=%s", # %c is a platform independent version of ./configure
   # this is the default for install:
   alien_install_commands => [
     "make install",
   alien_isolate_dynamic => 1,


NOTE: Please consider for new development of Aliens that you use Alien::Build and alienfile instead. Like this module they work with Alien::Base. Unlike this module they are more easily customized and handle a number of corner cases better. For a good place to start, please see Alien::Build::Manual::AlienAuthor. Although the Alien-Base / Alien-Build team will continue to maintain this module, (we will continue to fix bugs where appropriate), we aren't adding any new features to this module.

This is a subclass of Module::Build, that with Alien::Base allows for easy creation of Alien distributions. This module is used during the build step of your distribution. When properly configured it will

use pkg-config to find and use the system version of the library
download, build and install the library if the system does not provide it



[version 0.001]

 my $version = $abmb->alien_check_installed_version;

This function determines if the library is already installed as part of the operating system, and returns the version as a string. If it can't be detected then it should return empty list.

The default implementation relies on pkg-config, but you will probably want to override this with your own implementation if the package you are building does not use pkg-config.


[version 0.006]

 my $version = $amb->alien_check_built_version;

This function determines the version of the library after it has been built from source. This function only gets called if the operating system version can not be found and the package is successfully built. The version is returned on success. If the version can't be detected then it should return empty list. Note that failing to detect a version is considered a failure and the corresponding ./Build action will fail!

Any string is valid as a version as far as Alien::Base is concerned. The most useful value would be a number or dotted decimal that most software developers recognize and that software tools can differentiate. In some cases packages will not have a clear version number, in which case the string unknown would be a reasonable choice.

The default implementation relies on pkg-config, and other heuristics, but you will probably want to override this with your own implementation if the package you are building does not use pkg-config.

When this method is called, the current working directory will be the build root.

If you see an error message like this:

 Library looks like it installed, but no version was determined

After the package is built from source code then you probably need to provide an implementation for this method.


[version 0.024]

  my $dir = $amb->alien_extract_archive($filename);

This function unpacks the given archive and returns the directory containing the unpacked files.

The default implementation relies on Archive::Extract that is able to handle most common formats. In order to handle other formats or archives requiring some special treatment you may want to override this method.


[version 0.024]

  my %result = $amb->alien_do_system($cmd)

Similar to Module::Build's do_system, also sets the path and several environment variables in accordance to the object configuration (i.e. alien_bin_requires) and performs the interpolation of the patterns described in "COMMAND INTERPOLATION" in Alien::Base::ModuleBuild::API.

Returns a set of key value pairs including stdout, stderr, success and command.



Executes the commands for the given phase.


 my $string = $amb->alien_interpolate($string);

Takes the input string and interpolates the results.


[version 1.16]

 my $bool = $amb->alien_install_network;

Returns true if downloading source from the internet is allowed. This is true unless ALIEN_INSTALL_NETWORK is defined and false.


[version 1.16]

 my $rule = $amb->alien_download_rule;

This will return one of warn, digest, encrypt, digest_or_encrypt or digest_and_encrypt. This is based on the ALIEN_DOWNLOAD_RULE environment variable.


The documentation for Module::Build is broken up into sections:

General Usage (Module::Build)

This is the landing document for Alien::Base::ModuleBuild's parent class. It describes basic usage and background information. Its main purpose is to assist the user who wants to learn how to invoke and control Module::Build scripts at the command line.

It also lists the extra documentation for its use. Users and authors of Alien:: modules should familiarize themselves with these documents. Module::Build::API is of particular importance to authors.

Alien-Specific Usage (Alien::Base::ModuleBuild)

This is the document you are currently reading.

Authoring Reference (Alien::Base::Authoring)

This document describes the structure and organization of Alien::Base based projects, beyond that contained in Module::Build::Authoring, and the relevant concepts needed by authors who are writing Build.PL scripts for a distribution or controlling Alien::Base::ModuleBuild processes programmatically.

Note that as it contains information both for the build and use phases of Alien::Base projects, it is located in the upper namespace.

API Reference (Alien::Base::ModuleBuild::API)

This is a reference to the Alien::Base::ModuleBuild API beyond that contained in Module::Build::API.

Using the resulting Alien (Alien::Build::Manual::AlienUser)

Once you have an Alien you or your users can review this manual for how to use it. Generally speaking you should have some useful usage information in your Alien's POD, but some authors choose to direct their users to this manual instead.

Using Alien::Build instead (Alien::Build::Manual)

As mentioned at the top, you are encouraged to use the Alien::Build and alienfile system instead. This manual is a starting point for the other Alien::Build documentation.



Set to a true value to install to an arch-specific directory.


This controls security options for fetching alienized packages over the internet. The legal values are:


Warn if the package is either unencrypted or lacks a digest. This is currently the default, but will change in the near future.


Fetch will not happen unless there is a digest for the alienized package.


Fetch will not happen unless via an encrypted protocol like https, or if the package is bundled with the Alien.


Fetch will only happen if the alienized package has a cryptographic signature digest, or if an encrypted protocol like https is used, or if the package is bundled with the Alien. This will be the default in the near future.


Fetch will only happen if the alienized package has a cryptographic signature digest, and is fetched via a secure protocol (like https). Bundled packages are also considered fetch via a secure protocol, but will still require a digest.


Skips checking for an installed version and forces reinstalling the Alien target.


If true (the default if not defined), then network installs will be allowed. Set to 0 or another false value to turn off network installs.


Set to share or system to override the install type. Set to default or unset to restore the default.


Enables verbose output from M::B::do_system.


Overrides $KEY in the given module's repository configuration matching $PROTOCOL. For example,




Thanks also to

Christian Walde (Mithaldu)

For productive conversations about component interoperability.


For writing Alien::Tidyp from which I drew many of my initial ideas.

David Mertens (run4flat)

For productive conversations about implementation.

Mark Nunberg (mordy, mnunberg)

For graciously teaching me about rpath and dynamic loading,


Original author: Joel A Berger <>

Current maintainer: Graham Ollis <>


David Mertens (run4flat)

Mark Nunberg (mordy, mnunberg)

Christian Walde (Mithaldu)

Brian Wightman (MidLifeXis)

Graham Ollis (plicease)

Zaki Mughal (zmughal)


Vikas N Kumar (vikasnkumar)

Flavio Poletti (polettix)

Salvador Fandiño (salva)

Gianni Ceccarelli (dakkar)

Pavel Shaydo (zwon, trinitum)

Kang-min Liu (劉康民, gugod)

Nicholas Shipp (nshp)

Petr Písař (ppisar)

Alberto Simões (ambs)


This software is copyright (c) 2012-2022 by Joel A Berger.

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