Provided by: libextutils-autoinstall-perl_0.64-1_all bug


       ExtUtils::AutoInstall - Automatic install of dependencies via CPAN


       This document describes version 0.63 of ExtUtils::AutoInstall, released September 12,


       In Makefile.PL, with Module::Install available on the author's system:

           use inc::Module::Install;

           name        ('Joe-Hacker');
           abstract    ('Perl Interface to Joe Hacker');
           author      ('Joe Hacker <>');
           include     ('ExtUtils::AutoInstall');

           requires    ('Module0');            # mandatory modules
           features    (
               -config         => {
                   make_args   => '--hello',   # option(s) for CPAN::Config
                   force       => 1,           # pseudo-option to force install
                   do_once     => 1,           # skip previously failed modules
               'Feature1' => [
                   'Module2'   => '0.1',
               'Feature2' => [
                   'Module3'   => '1.0',

       Invoking the resulting Makefile.PL:

           % perl Makefile.PL                  # interactive behaviour
           % perl Makefile.PL --defaultdeps    # accept default value on prompts
           % perl Makefile.PL --checkdeps      # check only, no Makefile produced
           % perl Makefile.PL --skipdeps       # ignores all dependencies
           % perl Makefile.PL --testonly       # don't write installation targets

       Note that the trailing 'deps' of arguments may be omitted, too.

       Using "--defaultdeps" will make Makefile.PL behave similarly to a regular Makefile.PL file
       with "PREREQ_PM" dependencies.

       One can use environment variables (see "ENVIRONMENT") below to set a default behavior
       instead of specifying it in the command line for every invocation of Makefile.PL.

       Using make (or nmake):

           % make [all|test|install]           # install dependencies first
           % make checkdeps                    # same as the --checkdeps above
           % make installdeps                  # install dependencies only


       ExtUtils::AutoInstall lets module writers to specify a more sophisticated form of
       dependency information than the "PREREQ_PM" option offered by ExtUtils::MakeMaker.

       This module works best with the Module::Install framework, a drop-in replacement for
       MakeMaker.  However, this module also supports Makefile.PL files based on MakeMaker; see
       "EXAMPLES" for instructions.

   Prerequisites and Features
       Prerequisites are grouped into features, and the user could choose yes/no on each one's
       dependencies; the module writer may also supply a boolean value via "-default" to specify
       the default choice.

       The Core Features marked by the name "-core" will double-check with the user, if the user
       chooses not to install the mandatory modules.  This differs from the pre-0.26 'silent
       install' behaviour.

       Starting from version 0.27, if "-core" is set to the string "all" (case-insensitive),
       every feature will be considered mandatory.

       The dependencies are expressed as pairs of "Module" => "version" inside an array
       reference.  If the order does not matter, and there are no "-default", "-tests" or
       "-skiptests" directives for that feature, you may also use a hash reference.

   The Installation Process
       Once ExtUtils::AutoInstall has determined which module(s) are needed, it checks whether
       it's running under the CPAN shell and should therefore let CPAN handle the dependency.

       Finally, the "WriteMakefile()" is overridden to perform some additional checks, as well as
       skips tests associated with disabled features by the "-tests" option.

       The actual installation happens at the end of the "make config" target; both "make test"
       and "make install" will trigger the installation of required modules.

       If it's not running under CPAN, the installer will probe for an active connection by
       trying to resolve the domain "", and check for the user's permission to use CPAN.
       If all went well, a separate
           CPAN instance is created to install the required modules.

       If you have the CPANPLUS package installed in your system, it is preferred by default over
       CPAN; it also accepts some extra options (e.g. "-target => 'skiptest', -skiptest => 1" to
       skip testing).

       All modules scheduled to be installed will be deleted from %INC first, so
       ExtUtils::MakeMaker will check the newly installed modules.

       Additionally, you could use the "make installdeps" target to install the modules, and the
       "make checkdeps" target to check dependencies without actually installing them; the "perl
       Makefile.PL --checkdeps" command has an equivalent effect.

       If the Makefile.PL itself needs to use an independent module (e.g.  Acme::KillarApp, v1.21
       or greater), then use something like below:

           BEGIN {
               require ExtUtils::AutoInstall;
               # the first argument is an arrayref of the -config flags
               ExtUtils::AutoInstall->install([], 'Acme::KillerApp' => 1.21);
           use Acme::KillerApp 1.21;

               # ... arguments as usual ...

       Note the version test in the use clause; if you are so close to the cutting edge that
       Acme::KillerApp 1.20 is the latest version on CPAN, this will prevent your module from
       going awry.

   User-Defined Hooks
       User-defined pre-installation and post-installation hooks are available via
       "MY::preinstall" and "MY::postinstall" subroutines, as shown below:

           # pre-install handler; takes $module_name and $version
           sub MY::preinstall  { return 1; } # return false to skip install

           # post-install handler; takes $module_name, $version, $success
           sub MY::postinstall { return; }   # the return value doesn't matter

       Note that since ExtUtils::AutoInstall performs installation at the time of "use" (i.e.
       before perl parses the remainder of Makefile.PL), you have to declare those two handlers
       before the "use" statement for them to take effect.

       If the user did not choose to install a module or it already exists on the system, neither
       of the handlers is invoked.  Both handlers are invoked exactly once for each module when
       installation is attempted.

       "MY::preinstall" takes two arguments, $module_name and $version; if it returns a false
       value, installation for that module will be skipped, and "MY::postinstall" won't be called
       at all.

       "MY::postinstall" takes three arguments, $module_name, $version and $success.  The last
       one denotes whether the installation succeeded or not: 1 means installation completed
       successfully, 0 means failure during install, and "undef" means that the installation was
       not attempted at all, possibly due to connection problems, or that module does not exist
       on CPAN at all.

   Customized "MY::postamble"
       Starting from version 0.43, ExtUtils::AutoInstall supports modules that require a
       "MY::postamble" subroutine in their Makefile.PL.  The user-defined "MY::postamble", if
       present, is responsible for calling "ExtUtils::AutoInstall::postamble" and include the
       output in its return value.

       For example, the DBD::* (database driver) modules for the Perl DBI are required to include
       the postamble generated by the function "dbd_postamble", so their Makefile.PL may contain
       lines like this:

           sub MY::postamble {
               return &ExtUtils::AutoInstall::postamble . &dbd_postamble;

       Note that the ExtUtils::AutoInstall module does not export the "postamble" function, so
       the name should always be fully qualified.


       ExtUtils::AutoInstall will add "UNINST=1" to your make install flags if your effective uid
       is 0 (root), unless you explicitly disable it by setting CPAN's "make_install_arg"
       configuration option (or the "makeflags" option of CPANPLUS) to include "UNINST=0".  This
       may cause dependency problems if you are using a fine-tuned directory structure for your
       site.  Please consult "FAQ" in CPAN for an explanation in detail.

       If either version or Sort::Versions is available, they will be used to compare the
       required version with the existing module's version and the CPAN module's.  Otherwise it
       silently falls back to use cmp.  This may cause inconsistent behaviours in pathetic


       Since this module is needed before writing Makefile, it makes little use as a CPAN module;
       hence each distribution must include it in full.  The only alternative I'm aware of,
       namely prompting in Makefile.PL to force user install it (cf. the Template Toolkit's
       dependency on AppConfig) is not very desirable either.

       The current compromise is to add the bootstrap code listed in the "SYNOPSIS" before every
       script, but that does not look pretty, and will not work without an Internet connection.

       Since we do not want all future options of ExtUtils::AutoInstall to be painfully detected
       manually like above, this module provides a bootstrapping mechanism via the "-version"
       flag.  If a newer version is needed by the Makefile.PL, it will go ahead to fetch a new
       version, reload it into memory, and pass the arguments forward.

       If you have any suggestions, please let me know.  Thanks.


       ExtUtils::AutoInstall uses a single environment variable, "PERL_EXTUTILS_AUTOINSTALL".  It
       is taken as the command line argument passed to Makefile.PL; you could set it to either
       "--defaultdeps" or "--skipdeps" to avoid interactive behaviour.


   Using MakeMaker with AutoInstall
       To use this module with ExtUtils::MakeMaker, first make a inc/ExtUtils/ subdirectory in
       the directory containing your Makefile.PL, and put a copy this module under it as
       inc/ExtUtils/  You can find out where this module has been installed by
       typing "perldoc -l ExtUtils::AutoInstall" in the command line.

       Your Makefile.PL should look like this:

           # pull in ExtUtils/ from 'inc'
           use lib 'inc';
           use ExtUtils::AutoInstall (
               -core           => [            # mandatory modules
                   'Module0'   => '',          # any version would suffice
               'Feature1'      => [
                   # do we want to install this feature by default?
                   -default    => ( system('feature1 --version') == 0 ),
                   Module1     => '0.01',
               'Feature2'      => [
                   # associate tests to be disabled if this feature is missing
                   -tests      => [ <t/feature2*.t> ],
                   # associate tests to be disabled if this feature is present
                   -skiptests  => [ <t/nofeature2*.t> ],
                   Module2     => '0.02',
               'Feature3'      => {            # hash reference works, too
                   # force installation even if tests fail
                   Module2     => '0.03',

               AUTHOR          => 'Joe Hacker <>',
               ABSTRACT        => 'Perl Interface to Joe Hacker',
               NAME            => 'Joe::Hacker',
               VERSION_FROM    => '',
               DISTNAME        => 'Joe-Hacker',

   Self-Download Code
       If you do not wish to put a copy of ExtUtils::AutoInstall under inc/, and are confident
       that users will have internet access, you may replace the "use lib 'inc';" line with this
       block of code:

           # ExtUtils::AutoInstall Bootstrap Code, version 7.
           or+eval"use $p $v;1"or+do{my$e=$ENV{PERL_EXTUTILS_AUTOINSTALL};
           (!defined($e)||$e!~m/--(?:default|skip|testonly)/and-t STDIN or
           eval"use ExtUtils::MakeMaker;WriteMakefile(PREREQ_PM=>{'$p',$v}
           );1"and exit)and print"==> $p $v required. Install it from CP".
           "AN? [Y/n] "and<STDIN>!~/^n/i and print"*** Installing $p\n"and
           do{if (eval '$>' and lc(`sudo -V`) =~ /version/){system('sudo',
           $^X,"-MCPANPLUS","-e","CPANPLUS::install $p");eval"use $p $v;1"
           ||system('sudo', $^X, "-MCPAN", "-e", "CPAN::install $p")}eval{
           require CPANPLUS;CPANPLUS::install$p};eval"use $p $v;1"or eval{
           require CPAN;CPAN::install$p};eval"use $p $v;1"||die"*** Please
           manually install $p $v from first...\n"}}}

       If the user did not have ExtUtils::AutoInstall installed, the block of code above will
       automatically download and install it.

       However, due to its space-compressed (and obfuscated) nature, you should think twice
       before employing this block of code; it is usually much more desirable to just use
       Module::Install instead.


       perlmodlib, ExtUtils::MakeMaker, Sort::Versions, CPAN, CPANPLUS, Module::Install


       The test script included in the ExtUtils::AutoInstall distribution contains code adapted
       from Michael Schwern's Test::More under the Perl License.  Please consult to
       t/AutoInstall.t for details.

       See the AUTHORS file in this module's source distribution for the list of contributors.


       Autrijus Tang <>


       Copyright 2001, 2002, 2003, 2004, 2005, 2016 by Autrijus Tang <>.

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

       See <>