3 Module::Build::API - API Reference for Module Authors
8 I list here some of the most important methods in C<Module::Build>.
9 Normally you won't need to deal with these methods unless you want to
10 subclass C<Module::Build>. But since one of the reasons I created
11 this module in the first place was so that subclassing is possible
12 (and easy), I will certainly write more docs as the interface
24 This method returns a reasonable facsimile of the currently-executing
25 C<Module::Build> object representing the current build. You can use
26 this object to query its C<notes()> method, inquire about installed
27 modules, and so on. This is a great way to share information between
28 different parts of your build process. For instance, you can ask
29 the user a question during C<perl Build.PL>, then use their answer
30 during a regression test:
33 my $color = $build->prompt("What is your favorite color?");
34 $build->notes(color => $color);
38 my $build = Module::Build->current;
39 my $color = $build->notes('color');
42 The way the C<current()> method is currently implemented, there may be
43 slight differences between the C<$build> object in Build.PL and the
44 one in C<t/colortest.t>. It is our goal to minimize these differences
45 in future releases of Module::Build, so please report any anomalies
48 One important caveat: in its current implementation, C<current()> will
49 B<NOT> work correctly if you have changed out of the directory that
50 C<Module::Build> was invoked from.
56 Creates a new Module::Build object. Arguments to the new() method are
57 listed below. Most arguments are optional, but you must provide
58 either the C<module_name> argument, or C<dist_name> and one of
59 C<dist_version> or C<dist_version_from>. In other words, you must
60 provide enough information to determine both a distribution name and
70 An array reference of files to be cleaned up when the C<clean> action
71 is performed. See also the add_to_cleanup() method.
77 This parameter supports the setting of features (see
78 L<feature($name)>) automatically based on a set of prerequisites. For
79 instance, for a module that could optionally use either MySQL or
80 PostgreSQL databases, you might use C<auto_features> like this:
82 my $build = Module::Build->new
84 ...other stuff here...
87 description => "Interface with Postgres databases",
88 requires => { 'DBD::Pg' => 23.3,
89 'DateTime::Format::Pg' => 0 },
92 description => "Interface with MySQL databases",
93 requires => { 'DBD::mysql' => 17.9,
94 'DateTime::Format::MySQL' => 0 },
99 For each feature named, the required prerequisites will be checked, and
100 if there are no failures, the feature will be enabled (set to C<1>).
101 Otherwise the failures will be displayed to the user and the feature
102 will be disabled (set to C<0>).
104 See the documentation for L<requires> for the details of how
105 requirements can be specified.
111 An optional C<autosplit> argument specifies a file which should be run
112 through the C<Autosplit::autosplit()> function. If multiple files
113 should be split, the argument may be given as an array of the files to
116 In general I don't consider autosplitting a great idea, because it's
117 not always clear that autosplitting achieves its intended performance
118 benefits. It may even harm performance in environments like mod_perl,
119 where as much as possible of a module's code should be loaded during
126 The Module::Build class or subclass to use in the build
127 script. Defaults to "Module::Build" or the class name passed to or
128 created by a call to C<subclass()>. This property is useful if you're
129 writing a custom Module::Build subclass and have a bootstrapping
130 problem--that is, your subclass requires modules that may not be
131 installed when C<perl Build.PL> is executed, but you've listed in
132 C<build_requires> so that they should be available when C<./Build> is
139 Modules listed in this section are necessary to build and install the
140 given module, but are not necessary for regular usage of it. This is
141 actually an important distinction - it allows for tighter control over
142 the body of installed modules, and facilitates correct dependency
143 checking on binary/packaged distributions of the module.
145 See the documentation for L<Module::Build::Authoring/"PREREQUISITES">
146 for the details of how requirements can be specified.
148 =item create_packlist
152 If true, this parameter tells Module::Build to create a F<.packlist>
153 file during the C<install> action, just like ExtUtils::MakeMaker does.
154 The file is created in a subdirectory of the C<arch> installation
155 location. It is used by some other tools (CPAN, CPANPLUS, etc.) for
156 determining what files are part of an install.
158 The default value is true. This parameter was introduced in
159 Module::Build version 0.2609; previously no packlists were ever
160 created by Module::Build.
166 An optional C<c_source> argument specifies a directory which contains
167 C source files that the rest of the build may depend on. Any C<.c>
168 files in the directory will be compiled to object files. The
169 directory will be added to the search path during the compilation and
170 linking phases of any C or XS files.
176 Modules listed in this section conflict in some serious way with the
177 given module. C<Module::Build> (or some higher-level tool) will
178 refuse to install the given module if the given module/version is also
181 See the documentation for L<Module::Build::Authoring/"PREREQUISITES">
182 for the details of how requirements can be specified.
184 =item create_makefile_pl
188 This parameter lets you use Module::Build::Compat during the
189 C<distdir> (or C<dist>) action to automatically create a Makefile.PL
190 for compatibility with ExtUtils::MakeMaker. The parameter's value
191 should be one of the styles named in the Module::Build::Compat
198 This parameter tells Module::Build to automatically create a F<README>
199 file at the top level of your distribution. Currently it will simply
200 use C<Pod::Text> (or C<Pod::Readme> if it's installed) on the file
201 indicated by C<dist_version_from> and put the result in the F<README>
202 file. This is by no means the only recommended style for writing a
203 README, but it seems to be one common one used on the CPAN.
205 If you generate a F<README> in this way, it's probably a good idea to
206 create a separate F<INSTALL> file if that information isn't in the
213 This should be a short description of the distribution. This is used
214 when generating metadata for F<META.yml> and PPD files. If it is not
215 given then C<Module::Build> looks in the POD of the module from which
216 it gets the distribution's version. It looks for the first line
217 matching C<$package\s-\s(.+)>, and uses the captured text as the
224 This should be something like "John Doe <jdoe@example.com>", or if
225 there are multiple authors, an anonymous array of strings may be
226 specified. This is used when generating metadata for F<META.yml> and
227 PPD files. If this is not specified, then C<Module::Build> looks at
228 the module from which it gets the distribution's version. If it finds
229 a POD section marked "=head1 AUTHOR", then it uses the contents of
236 Specifies the name for this distribution. Most authors won't need to
237 set this directly, they can use C<module_name> to set C<dist_name> to
238 a reasonable default. However, some agglomerative distributions like
239 C<libwww-perl> or C<bioperl> have names that don't correspond directly
240 to a module name, so C<dist_name> can be set independently.
246 Specifies a version number for the distribution. See C<module_name>
247 or C<dist_version_from> for ways to have this set automatically from a
248 C<$VERSION> variable in a module. One way or another, a version
249 number needs to be set.
251 =item dist_version_from
255 Specifies a file to look for the distribution version in. Most
256 authors won't need to set this directly, they can use C<module_name>
257 to set it to a reasonable default.
259 The version is extracted from the specified file according to the same
260 rules as C<ExtUtils::MakeMaker> and C<CPAN.pm>. It involves finding
261 the first line that matches the regular expression
263 /([\$*])(([\w\:\']*)\bVERSION)\b.*\=/
265 eval()-ing that line, then checking the value of the C<$VERSION>
266 variable. Quite ugly, really, but all the modules on CPAN depend on
267 this process, so there's no real opportunity to change to something
274 A boolean flag indicating whether the F<Build.PL> file must be
275 executed, or whether this module can be built, tested and installed
276 solely from consulting its metadata file. The main reason to set this
277 to a true value is that your module performs some dynamic
278 configuration as part of its build/install process. If the flag is
279 omitted, the F<META.yml> spec says that installation tools should
280 treat it as 1 (true), because this is a safer way to behave.
282 Currently C<Module::Build> doesn't actually do anything with this flag
283 - it's up to higher-level tools like C<CPAN.pm> to do
284 something useful with it. It can potentially bring lots of security,
285 packaging, and convenience improvements.
287 =item extra_compiler_flags
289 =item extra_linker_flags
293 These parameters can contain array references (or strings, in which
294 case they will be split into arrays) to pass through to the compiler
295 and linker phases when compiling/linking C code. For example, to tell
296 the compiler that your code is C++, you might do:
298 my $build = Module::Build->new
300 module_name => 'Foo::Bar',
301 extra_compiler_flags => ['-x', 'c++'],
304 To link your XS code against glib you might write something like:
306 my $build = Module::Build->new
308 module_name => 'Foo::Bar',
310 extra_compiler_flags => scalar `glib-config --cflags`,
311 extra_linker_flags => scalar `glib-config --libs`,
318 You can pass arbitrary command line options to F<Build.PL> or
319 F<Build>, and they will be stored in the Module::Build object and can
320 be accessed via the C<args()> method. However, sometimes you want
321 more flexibility out of your argument processing than this allows. In
322 such cases, use the C<get_options> parameter to pass in a hash
323 reference of argument specifications, and the list of arguments to
324 F<Build.PL> or F<Build> will be processed according to those
325 specifications before they're passed on to C<Module::Build>'s own
328 The supported option specification hash keys are:
335 The type of option. The types are those supported by Getopt::Long; consult
336 its documentation for a complete list. Typical types are C<=s> for strings,
337 C<+> for additive options, and C<!> for negatable options. If the
338 type is not specified, it will be considered a boolean, i.e. no
339 argument is taken and a value of 1 will be assigned when the option is
344 A reference to a scalar in which to store the value passed to the option.
345 If not specified, the value will be stored under the option name in the
346 hash returned by the C<args()> method.
350 A default value for the option. If no default value is specified and no option
351 is passed, then the option key will not exist in the hash returned by
357 You can combine references to your own variables or subroutines with
358 unreferenced specifications, for which the result will also be stored in the
359 hash returned by C<args()>. For example:
362 my $build = Module::Build->new
364 module_name => 'Foo::Bar',
366 loud => { store => \$loud },
367 dbd => { type => '=s' },
368 quantity => { type => '+' },
372 print STDERR "HEY, ARE YOU LISTENING??\n" if $loud;
373 print "We'll use the ", $build->args('dbd'), " DBI driver\n";
374 print "Are you sure you want that many?\n"
375 if $build->args('quantity') > 2;
377 The arguments for such a specification can be called like so:
379 perl Build.PL --loud --dbd=DBD::pg --quantity --quantity --quantity
381 B<WARNING:> Any option specifications that conflict with Module::Build's own
382 options (defined by its properties) will throw an exception.
384 Consult the Getopt::Long documentation for details on its usage.
390 Specifies any additional directories in which to search for C header
391 files. May be given as a string indicating a single directory, or as
392 a list reference indicating multiple directories.
398 You can set paths for individual installable elements by using the
399 C<install_path> parameter:
401 my $build = Module::Build->new
403 ...other stuff here...
406 arch => '/foo/lib/arch',
414 Determines where files are installed within the normal perl hierarchy
415 as determined by F<Config.pm>. Valid values are: C<core>, C<site>,
416 C<vendor>. The default is C<site>. See
417 L<Module::Build/"INSTALL PATHS">
423 Specifies the licensing terms of your distribution. Valid options include:
430 The distribution is licensed under the Apache Software License
431 (http://opensource.org/licenses/apachepl.php).
435 The distribution is licensed under the Artistic License, as specified
436 by the F<Artistic> file in the standard perl distribution.
440 The distribution is licensed under the BSD License
441 (http://www.opensource.org/licenses/bsd-license.php).
445 The distribution is licensed under the terms of the Gnu General
446 Public License (http://www.opensource.org/licenses/gpl-license.php).
450 The distribution is licensed under the terms of the Gnu Lesser
451 General Public License
452 (http://www.opensource.org/licenses/lgpl-license.php).
456 The distribution is licensed under the MIT License
457 (http://opensource.org/licenses/mit-license.php).
461 The distribution is licensed under the Mozilla Public
462 License. (http://opensource.org/licenses/mozilla1.0.php or
463 http://opensource.org/licenses/mozilla1.1.php)
467 The distribution is licensed under some other Open Source
468 Initiative-approved license listed at
469 http://www.opensource.org/licenses/ .
473 The distribution may be copied and redistributed under the same terms
474 as perl itself (this is by far the most common licensing option for
475 modules on CPAN). This is a dual license, in which the user may
476 choose between either the GPL or the Artistic license.
480 The distribution may not be redistributed without special permission
481 from the author and/or copyright holder.
485 The distribution is licensed under a license that is B<not> approved
486 by www.opensource.org but that allows distribution without
492 Note that you must still include the terms of your license in your
493 documentation - this field only lets automated tools figure out your
494 licensing restrictions. Humans still need something to read. If you
495 choose to provide this field, you should make sure that you keep it in
496 sync with your written documentation if you ever change your licensing
499 It is a fatal error to use a license other than the ones mentioned
500 above. This is not because I wish to impose licensing terms on you -
501 please let me know if you would like another license option to be
502 added to the list. You may also use a license type of C<unknown> if
503 you don't wish to specify your terms (but this is usually not a good
504 idea for you to do!).
506 I just started out with a small set of licenses to keep things simple,
507 figuring I'd let people with actual working knowledge in this area
508 tell me what to do. So if that's you, drop me a line.
514 A hash of key/value pairs that should be added to the F<META.yml> file
515 during the C<distmeta> action. Any existing entries with the same
516 names will be overridden.
522 A hash of key/value pairs that should be merged into the F<META.yml>
523 file during the C<distmeta> action. Any existing entries with the
524 same names will be overridden.
526 The only difference between C<meta_add> and C<meta_merge> is their
527 behavior on hash-valued and array-valued entries: C<meta_add> will
528 completely blow away the existing hash or array value, but
529 C<meta_merge> will merge the supplied data into the existing hash or
536 The C<module_name> is a shortcut for setting default values of
537 C<dist_name> and C<dist_version_from>, reflecting the fact that the
538 majority of CPAN distributions are centered around one "main" module.
539 For instance, if you set C<module_name> to C<Foo::Bar>, then
540 C<dist_name> will default to C<Foo-Bar> and C<dist_version_from> will
541 default to C<lib/Foo/Bar.pm>. C<dist_version_from> will in turn be
542 used to set C<dist_version>.
544 Setting C<module_name> won't override a C<dist_*> parameter you
551 An optional parameter specifying a set of C<.PL> files in your
552 distribution. These will be run as Perl scripts prior to processing
553 the rest of the files in your distribution. They are usually used as
554 templates for creating other files dynamically, so that a file like
555 C<lib/Foo/Bar.pm.PL> might create the file C<lib/Foo/Bar.pm>.
557 The files are specified with the C<.PL> files as hash keys, and the
558 file(s) they generate as hash values, like so:
560 my $build = Module::Build->new
562 module_name => 'Foo::Bar',
564 PL_files => { 'lib/Foo/Bar.pm.PL' => 'lib/Foo/Bar.pm' },
567 Note that the path specifications are I<always> given in Unix-like
568 format, not in the style of the local system.
570 If your C<.PL> scripts don't create any files, or if they create files
571 with unexpected names, or even if they create multiple files, you can
572 indicate that so that Module::Build can properly handle these created
576 'lib/Foo/Bar.pm.PL' => 'lib/Foo/Bar.pm',
577 'lib/something.PL' => ['/lib/something', '/lib/else'],
578 'lib/funny.PL' => [],
585 An optional parameter specifying the set of C<.pm> files in this
586 distribution, specified as a hash reference whose keys are the files'
587 locations in the distributions, and whose values are their logical
588 locations based on their package name, i.e. where they would be found
589 in a "normal" Module::Build-style distribution. This parameter is
590 mainly intended to support alternative layouts of files.
592 For instance, if you have an old-style MakeMaker distribution for a
593 module called C<Foo::Bar> and a F<Bar.pm> file at the top level of the
594 distribution, you could specify your layout in your C<Build.PL> like
597 my $build = Module::Build->new
599 module_name => 'Foo::Bar',
601 pm_files => { 'Bar.pm' => 'lib/Foo/Bar.pm' },
604 Note that the values should include C<lib/>, because this is where
605 they would be found in a "normal" Module::Build-style distribution.
607 Note also that the path specifications are I<always> given in
608 Unix-like format, not in the style of the local system.
614 Just like C<pm_files>, but used for specifying the set of C<.pod>
615 files in your distribution.
621 This is just like the C<requires> argument, except that modules listed
622 in this section aren't essential, just a good idea. We'll just print
623 a friendly warning if one of these modules aren't found, but we'll
626 If a module is recommended but not required, all tests should still
627 pass if the module isn't installed. This may mean that some tests
628 may be skipped if recommended dependencies aren't present.
630 Automated tools like CPAN.pm should inform the user when recommended
631 modules aren't installed, and it should offer to install them if it
634 See the documentation for L<Module::Build::Authoring/"PREREQUISITES">
635 for the details of how requirements can be specified.
637 =item recursive_test_files
641 Normally, C<Module::Build> does not search subdirectories when looking
642 for tests to run. When this options is set it will search recursively
643 in all subdirectories of the standard 't' test directory.
649 An optional C<requires> argument specifies any module prerequisites
650 that the current module depends on.
652 One note: currently C<Module::Build> doesn't actually I<require> the
653 user to have dependencies installed, it just strongly urges. In the
654 future we may require it. There's also a C<recommends> section for
655 things that aren't absolutely required.
657 Automated tools like CPAN.pm should refuse to install a module if one
658 of its dependencies isn't satisfied, unless a "force" command is given
659 by the user. If the tools are helpful, they should also offer to
660 install the dependencies.
662 A synonym for C<requires> is C<prereq>, to help succour people
663 transitioning from C<ExtUtils::MakeMaker>. The C<requires> term is
664 preferred, but the C<prereq> term will remain valid in future
667 See the documentation for L<Module::Build::Authoring/"PREREQUISITES">
668 for the details of how requirements can be specified.
674 An optional parameter specifying a set of files that should be
675 installed as executable perl scripts when the module is installed.
676 May be given as an array reference of the files, or as a hash
677 reference whose keys are the files (and whose values will currently be
680 The default is to install no script files - in other words, there is
681 no default location where Module::Build will look for script files to
684 For backward compatibility, you may use the parameter C<scripts>
685 instead of C<script_files>. Please consider this usage deprecated,
686 though it will continue to exist for several version releases.
692 If a true value is specified for this parameter, C<Module::Signature>
693 will be used (via the 'distsign' action) to create a SIGNATURE file
694 for your distribution during the 'distdir' action, and to add the
695 SIGNATURE file to the MANIFEST (therefore, don't add it yourself).
697 The default value is false. In the future, the default may change to
698 true if you have C<Module::Signature> installed on your system.
704 An optional parameter specifying a set of files that should be used as
705 C<Test::Harness>-style regression tests to be run during the C<test>
706 action. May be given as an array reference of the files, or as a hash
707 reference whose keys are the files (and whose values will currently be
708 ignored). If the argument is given as a single string (not in an
709 array reference), that string will be treated as a C<glob()> pattern
710 specifying the files to use.
712 The default is to look for a F<test.pl> script in the top-level
713 directory of the distribution, and any files matching the glob pattern
714 C<*.t> in the F<t/> subdirectory. If the C<recursive_test_files>
715 property is true, then the C<t/> directory will be scanned recursively
723 Just like C<pm_files>, but used for specifying the set of C<.xs>
724 files in your distribution.
729 =item new_from_context(%args)
733 When called from a directory containing a F<Build.PL> script and a
734 F<META.yml> file (in other words, the base directory of a
735 distribution), this method will run the F<Build.PL> and return the
736 resulting C<Module::Build> object to the caller. Any key-value
737 arguments given to C<new_from_context()> are essentially like
738 command line arguments given to the F<Build.PL> script, so for example
739 you could pass C<< verbose => 1 >> to this method to turn on
746 You'll probably never call this method directly, it's only called from
747 the auto-generated C<Build> script. The C<new()> method is only
748 called once, when the user runs C<perl Build.PL>. Thereafter, when
749 the user runs C<Build test> or another action, the C<Module::Build>
750 object is created using the C<resume()> method to re-instantiate with
751 the settings given earlier to C<new()>.
757 This creates a new C<Module::Build> subclass on the fly, as described
758 in the L<Module::Build::Authoring/"SUBCLASSING"> section. The caller
759 must provide either a C<class> or C<code> parameter, or both. The
760 C<class> parameter indicates the name to use for the new subclass, and
761 defaults to C<MyModuleBuilder>. The C<code> parameter specifies Perl
762 code to use as the body of the subclass.
771 =item add_build_element($type)
775 Adds a new type of entry to the build process. Accepts a single
776 string specifying its type-name. There must also be a method defined
777 to process things of that type, e.g. if you add a build element called
778 C<'foo'>, then you must also define a method called
779 C<process_foo_files()>.
782 L<Module::Build::Cookbook/"Adding new file types to the build process">.
784 =item add_to_cleanup(@files)
788 You may call C<< $self->add_to_cleanup(@patterns) >> to tell
789 C<Module::Build> that certain files should be removed when the user
790 performs the C<Build clean> action. The arguments to the method are
791 patterns suitable for passing to Perl's C<glob()> function, specified
792 in either Unix format or the current machine's native format. It's
793 usually convenient to use Unix format when you hard-code the filenames
794 (e.g. in F<Build.PL>) and the native format when the names are
795 programmatically generated (e.g. in a testing script).
797 I decided to provide a dynamic method of the C<$build> object, rather
798 than just use a static list of files named in the F<Build.PL>, because
799 these static lists can get difficult to manage. I usually prefer to
800 keep the responsibility for registering temporary files close to the
801 code that creates them.
807 my $args_href = $build->args;
808 my %args = $build->args;
809 my $arg_value = $build->args($key);
810 $build->args($key, $value);
812 This method is the preferred interface for retrieving the arguments passed via
813 command line options to F<Build.PL> or F<Build>, minus the Module-Build
816 When called in in a scalar context with no arguments, this method returns a
817 reference to the hash storing all of the arguments; in an array context, it
818 returns the hash itself. When passed a single argument, it returns the value
819 stored in the args hash for that option key. When called with two arguments,
820 the second argument is assigned to the args hash under the key passed as the
823 =item autosplit_file($from, $to)
827 Invokes the C<AutoSplit> module on the C<$from> file, sending the
828 output to the C<lib/auto> directory inside C<$to>. C<$to> is
829 typically the C<blib/> directory.
835 Returns a string containing the root-level directory of this build,
836 i.e. where the C<Build.PL> script and the C<lib> directory can be
837 found. This is usually the same as the current working directory,
838 because the C<Build> script will C<chdir()> into this directory as
839 soon as it begins execution.
841 =item build_requires()
845 Returns a hash reference indicating the C<build_requires>
846 prerequisites that were passed to the C<new()> method.
848 =item check_installed_status($module, $version)
852 This method returns a hash reference indicating whether a version
853 dependency on a certain module is satisfied. The C<$module> argument
854 is given as a string like C<"Data::Dumper"> or C<"perl">, and the
855 C<$version> argument can take any of the forms described in L<requires>
856 above. This allows very fine-grained version checking.
858 The returned hash reference has the following structure:
861 ok => $whether_the_dependency_is_satisfied,
862 have => $version_already_installed,
863 need => $version_requested, # Same as incoming $version argument
864 message => $informative_error_message,
867 If no version of C<$module> is currently installed, the C<have> value
868 will be the string C<< "<none>" >>. Otherwise the C<have> value will
869 simply be the version of the installed module. Note that this means
870 that if C<$module> is installed but doesn't define a version number,
871 the C<have> value will be C<undef> - this is why we don't use C<undef>
872 for the case when C<$module> isn't installed at all.
874 This method may be called either as an object method
875 (C<< $build->check_installed_status($module, $version) >>)
877 (C<< Module::Build->check_installed_status($module, $version) >>).
879 =item check_installed_version($module, $version)
883 Like C<check_installed_status()>, but simply returns true or false
884 depending on whether module C<$module> satisfies the dependency
887 If the check succeeds, the return value is the actual version of
888 C<$module> installed on the system. This allows you to do the
891 my $installed = $build->check_installed_version('DBI', '1.15');
893 print "Congratulations, version $installed of DBI is installed.\n";
895 die "Sorry, you must install DBI.\n";
898 If the check fails, we return false and set C<$@> to an informative
901 If C<$version> is any non-true value (notably zero) and any version of
902 C<$module> is installed, we return true. In this case, if C<$module>
903 doesn't define a version, or if its version is zero, we return the
904 special value "0 but true", which is numerically zero, but logically
907 In general you might prefer to use C<check_installed_status> if you
908 need detailed information, or this method if you just need a yes/no
911 =item compare_versions($v1, $op, $v2)
915 Compares two module versions C<$v1> and C<$v2> using the operator
916 C<$op>, which should be one of Perl's numeric operators like C<!=> or
917 C<< >= >> or the like. We do at least a halfway-decent job of
918 handling versions that aren't strictly numeric, like C<0.27_02>, but
919 exotic stuff will likely cause problems.
921 In the future, the guts of this method might be replaced with a call
922 out to C<version.pm>.
926 =item config($key, $value)
928 =item config() [deprecated]
932 With a single argument C<$key>, returns the value associated with that
933 key in the C<Config.pm> hash, including any changes the author or user
936 With C<$key> and C<$value> arguments, sets the value for future
937 callers of C<config($key)>.
939 With no arguments, returns a hash reference containing all such
940 key-value pairs. This usage is deprecated, though, because it's a
941 resource hog and violates encapsulation.
943 =item config_data($name)
945 =item config_data($name => $value)
949 With a single argument, returns the value of the configuration
950 variable C<$name>. With two arguments, sets the given configuration
951 variable to the given value. The value may be any perl scalar that's
952 serializable with C<Data::Dumper>. For instance, if you write a
953 module that can use a MySQL or PostgreSQL back-end, you might create
954 configuration variables called C<mysql_connect> and
955 C<postgres_connect>, and set each to an array of connection parameters
956 for C<< DBI->connect() >>.
958 Configuration values set in this way using the Module::Build object
959 will be available for querying during the build/test process and after
960 installation via the generated C<...::ConfigData> module, as
961 C<< ...::ConfigData->config($name) >>.
963 The C<feature()> and C<config_data()> methods represent
964 Module::Build's main support for configuration of installed modules.
965 See also L<Module::Build::Authoring/"SAVING CONFIGURATION INFORMATION">.
971 Returns a hash reference indicating the C<conflicts> prerequisites
972 that were passed to the C<new()> method.
974 =item contains_pod($file)
978 [Deprecated] Please see L<Module::Build::ModuleInfo> instead.
980 Returns true if the given file appears to contain POD documentation.
981 Currently this checks whether the file has a line beginning with
982 '=pod', '=head', or '=item', but the exact semantics may change in the
985 =item copy_if_modified(%parameters)
989 Takes the file in the C<from> parameter and copies it to the file in
990 the C<to> parameter, or the directory in the C<to_dir> parameter, if
991 the file has changed since it was last copied (or if it doesn't exist
992 in the new location). By default the entire directory structure of
993 C<from> will be copied into C<to_dir>; an optional C<flatten>
994 parameter will copy into C<to_dir> without doing so.
996 Returns the path to the destination file, or C<undef> if nothing
999 Any directories that need to be created in order to perform the
1000 copying will be automatically created.
1002 The destination file is set to read-only. If the source file has the
1003 executable bit set, then the destination file will be made executable.
1005 =item create_build_script()
1009 Creates an executable script called C<Build> in the current directory
1010 that will be used to execute further user actions. This script is
1011 roughly analogous (in function, not in form) to the Makefile created
1012 by C<ExtUtils::MakeMaker>. This method also creates some temporary
1013 data in a directory called C<_build/>. Both of these will be removed
1014 when the C<realclean> action is performed.
1016 =item current_action()
1020 Returns the name of the currently-running action, such as "build" or
1021 "test". This action is not necessarily the action that was originally
1022 invoked by the user. For example, if the user invoked the "test"
1023 action, current_action() would initially return "test". However,
1024 action "test" depends on action "code", so current_action() will
1025 return "code" while that dependency is being executed. Once that
1026 action has completed, current_action() will again return "test".
1028 If you need to know the name of the original action invoked by the
1029 user, see L<invoked_action()> below.
1031 =item depends_on(@actions)
1035 Invokes the named action or list of actions in sequence. Using this
1036 method is preferred to calling the action explicitly because it
1037 performs some internal record-keeping, and it ensures that the same
1038 action is not invoked multiple times (note: in future versions of
1039 Module::Build it's conceivable that this run-only-once mechanism will
1040 be changed to something more intelligent).
1042 Note that the name of this method is something of a misnomer; it
1043 should really be called something like
1044 C<invoke_actions_unless_already_invoked()> or something, but for
1045 better or worse (perhaps better!) we were still thinking in
1046 C<make>-like dependency terms when we created this method.
1048 See also C<dispatch()>. The main distinction between the two is that
1049 C<depends_on()> is meant to call an action from inside another action,
1050 whereas C<dispatch()> is meant to set the very top action in motion.
1052 =item dir_contains($first_dir, $second_dir)
1056 Returns true if the first directory logically contains the second
1057 directory. This is just a convenience function because C<File::Spec>
1058 doesn't really provide an easy way to figure this out (but
1059 C<Path::Class> does...).
1061 =item dispatch($action, %args)
1065 Invokes the build action C<$action>. Optionally, a list of options
1066 and their values can be passed in. This is equivalent to invoking an
1067 action at the command line, passing in a list of options.
1069 Custom options that have not been registered must be passed in as a
1070 hash reference in a key named "args":
1072 $build->dispatch('foo', verbose => 1, args => { my_option => 'value' });
1074 This method is intended to be used to programmatically invoke build
1075 actions, e.g. by applications controlling Module::Build-based builds
1076 rather than by subclasses.
1078 See also C<depends_on()>. The main distinction between the two is that
1079 C<depends_on()> is meant to call an action from inside another action,
1080 whereas C<dispatch()> is meant to set the very top action in motion.
1086 Returns the name of the directory that will be created during the
1087 C<dist> action. The name is derived from the C<dist_name> and
1088 C<dist_version> properties.
1094 Returns the name of the current distribution, as passed to the
1095 C<new()> method in a C<dist_name> or modified C<module_name>
1098 =item dist_version()
1102 Returns the version of the current distribution, as determined by the
1103 C<new()> method from a C<dist_version>, C<dist_version_from>, or
1104 C<module_name> parameter.
1106 =item do_system($cmd, @args)
1110 This is a fairly simple wrapper around Perl's C<system()> built-in
1111 command. Given a command and an array of optional arguments, this
1112 method will print the command to C<STDOUT>, and then execute it using
1113 Perl's C<system()>. It returns true or false to indicate success or
1114 failure (the opposite of how C<system()> works, but more intuitive).
1116 Note that if you supply a single argument to C<do_system()>, it
1117 will/may be processed by the systems's shell, and any special
1118 characters will do their special things. If you supply multiple
1119 arguments, no shell will get involved and the command will be executed
1122 =item feature($name)
1124 =item feature($name => $value)
1128 With a single argument, returns true if the given feature is set.
1129 With two arguments, sets the given feature to the given boolean value.
1130 In this context, a "feature" is any optional functionality of an
1131 installed module. For instance, if you write a module that could
1132 optionally support a MySQL or PostgreSQL backend, you might create
1133 features called C<mysql_support> and C<postgres_support>, and set them
1134 to true/false depending on whether the user has the proper databases
1135 installed and configured.
1137 Features set in this way using the Module::Build object will be
1138 available for querying during the build/test process and after
1139 installation via the generated C<...::ConfigData> module, as
1140 C<< ...::ConfigData->feature($name) >>.
1142 The C<feature()> and C<config_data()> methods represent
1143 Module::Build's main support for configuration of installed modules.
1144 See also L<Module::Build::Authoring/"SAVING CONFIGURATION INFORMATION">.
1146 =item have_c_compiler()
1150 Returns true if the current system seems to have a working C compiler.
1151 We currently determine this by attempting to compile a simple C source
1152 file and reporting whether the attempt was successful.
1154 =item install_base_relpaths()
1156 =item install_base_relpaths($type)
1158 =item install_base_relpaths($type => $path)
1162 Set or retrieve the relative paths that are appended to
1163 C<install_base> for any installable element. This is useful if you
1164 want to set the relative install path for custom build elements.
1166 With no argument, it returns a reference to a hash containing all
1167 elements and their respective values. This hash should not be modified
1168 directly; use the multi-argument below form to change values.
1170 The single argument form returns the value associated with the
1173 The multi-argument form allows you to set the paths for element types.
1174 C<$value> must be a relative path using unix-like paths. (A series of
1175 directories seperated by slashes. Eg 'foo/bar'.) The return value is a
1176 localized path based on C<$value>.
1178 Assigning the value C<undef> to an element causes it to be removed.
1180 =item install_destination($type)
1184 Returns the directory in which items of type C<$type> (e.g. C<lib>,
1185 C<arch>, C<bin>, or anything else returned by the C<install_types()>
1186 method) will be installed during the C<install> action. Any settings
1187 for C<install_path>, C<install_base>, and C<prefix> are taken into
1188 account when determining the return value.
1190 =item install_path()
1192 =item install_path($type)
1194 =item install_path($type => $path)
1198 Set or retrieve paths for specific installable elements. This is
1199 useful when you want to examine any explicit install paths specified
1200 by the user on the command line, or if you want to set the install
1201 path for a specific installable element based on another attribute
1202 like C<install_base()>.
1204 With no argument, it returns a reference to a hash containing all
1205 elements and their respective values. This hash should not be modified
1206 directly; use the multi-argument below form to change values.
1208 The single argument form returns the value associated with the
1211 The multi-argument form allows you to set the paths for element types.
1212 The supplied C<$path> should be an absolute path to install elements
1213 of C<$type>. The return value is C<$path>.
1215 Assigning the value C<undef> to an element causes it to be removed.
1217 =item install_types()
1221 Returns a list of installable types that this build knows about.
1222 These types each correspond to the name of a directory in F<blib/>,
1223 and the list usually includes items such as C<lib>, C<arch>, C<bin>,
1224 C<script>, C<libdoc>, C<bindoc>, and if HTML documentation is to be
1225 built, C<libhtml> and C<binhtml>. Other user-defined types may also
1228 =item invoked_action()
1232 This is the name of the original action invoked by the user. This
1233 value is set when the user invokes F<Build.PL>, the F<Build> script,
1234 or programatically through the L<dispatch()> method. It does not
1235 change as sub-actions are executed as dependencies are evaluated.
1237 To get the name of the currently executing dependency, see
1238 L<current_action()> above.
1244 =item notes($key => $value)
1248 The C<notes()> value allows you to store your own persistent
1249 information about the build, and to share that information among
1250 different entities involved in the build. See the example in the
1251 C<current()> method.
1253 The C<notes()> method is essentally a glorified hash access. With no
1254 arguments, C<notes()> returns the entire hash of notes. With one argument,
1255 C<notes($key)> returns the value associated with the given key. With two
1256 arguments, C<notes($key, $value)> sets the value associated with the given key
1257 to C<$value> and returns the new value.
1259 The lifetime of the C<notes> data is for "a build" - that is, the
1260 C<notes> hash is created when C<perl Build.PL> is run (or when the
1261 C<new()> method is run, if the Module::Build Perl API is being used
1262 instead of called from a shell), and lasts until C<perl Build.PL> is
1263 run again or the C<clean> action is run.
1269 Returns a string containing the working directory that was in effect
1270 before the F<Build> script chdir()-ed into the C<base_dir>. This
1271 might be useful for writing wrapper tools that might need to chdir()
1278 If you're subclassing Module::Build and some code needs to alter its
1279 behavior based on the current platform, you may only need to know
1280 whether you're running on Windows, Unix, MacOS, VMS, etc., and not the
1281 fine-grained value of Perl's C<$^O> variable. The C<os_type()> method
1282 will return a string like C<Windows>, C<Unix>, C<MacOS>, C<VMS>, or
1283 whatever is appropriate. If you're running on an unknown platform, it
1284 will return C<undef> - there shouldn't be many unknown platforms
1287 =item prefix_relpaths()
1289 =item prefix_relpaths($installdirs)
1291 =item prefix_relpaths($installdirs, $type)
1293 =item prefix_relpaths($installdirs, $type => $path)
1297 Set or retrieve the relative paths that are appended to C<prefix> for
1298 any installable element. This is useful if you want to set the
1299 relative install path for custom build elements.
1301 With no argument, it returns a reference to a hash containing all
1302 elements and their respective values as defined by the current
1303 C<installdirs> setting.
1305 With a single argument, it returns a reference to a hash containing
1306 all elements and their respective values as defined by
1309 The hash returned by the above calls should not be modified directly;
1310 use the three-argument below form to change values.
1312 The two argument form returns the value associated with the
1315 The multi-argument form allows you to set the paths for element types.
1316 C<$value> must be a relative path using unix-like paths. (A series of
1317 directories seperated by slashes. Eg 'foo/bar'.) The return value is a
1318 localized path based on C<$value>.
1320 Assigning the value C<undef> to an element causes it to be removed.
1322 =item prepare_metadata()
1326 This method is provided for authors to override to customize the
1327 fields of F<META.yml>. It is passed a YAML::Node node object which can
1328 be modified as desired and then returned. E.g.
1330 package My::Builder;
1331 use base 'Module::Build';
1333 sub prepare_metadata {
1335 my $node = $self->SUPER::prepare_metadata( shift );
1336 $node->{custom_field} = 'foo';
1340 =item prereq_failures()
1344 Returns a data structure containing information about any failed
1345 prerequisites (of any of the types described above), or C<undef> if
1346 all prerequisites are met.
1348 The data structure returned is a hash reference. The top level keys
1349 are the type of prerequisite failed, one of "requires",
1350 "build_requires", "conflicts", or "recommends". The associated values
1351 are hash references whose keys are the names of required (or
1352 conflicting) modules. The associated values of those are hash
1353 references indicating some information about the failure. For example:
1358 message => 'Version 0.42 is installed, but we need version 0.59',
1366 message => 'Prerequisite Foo isn't installed',
1369 This hash has the same structure as the hash returned by the
1370 C<check_installed_status()> method, except that in the case of
1371 "conflicts" dependencies we change the "need" key to "conflicts" and
1372 construct a proper message.
1376 # Check a required dependency on Foo::Bar
1377 if ( $build->prereq_failures->{requires}{Foo::Bar} ) { ...
1379 # Check whether there were any failures
1380 if ( $build->prereq_failures ) { ...
1382 # Show messages for all failures
1383 my $failures = $build->prereq_failures;
1384 while (my ($type, $list) = each %$failures) {
1385 while (my ($name, $hash) = each %$list) {
1386 print "Failure for $name: $hash->{message}\n";
1390 =item prereq_report()
1394 Returns a human-readable (table-form) string showing all
1395 prerequisites, the versions required, and the versions actually
1396 installed. This can be useful for reviewing the configuration of your
1397 system prior to a build, or when compiling data to send for a bug
1398 report. The C<prereq_report> action is just a thin wrapper around the
1399 C<prereq_report()> method.
1401 =item prompt($message, $default)
1405 Asks the user a question and returns their response as a string. The
1406 first argument specifies the message to display to the user (for
1407 example, C<"Where do you keep your money?">). The second argument,
1408 which is optional, specifies a default answer (for example,
1409 C<"wallet">). The user will be asked the question once.
1411 If C<prompt()> detects that it is not running interactively and there
1412 is nothing on STDIN or if the PERL_MM_USE_DEFAULT environment variable
1413 is set to true, the $default will be used without prompting. This
1414 prevents automated processes from blocking on user input.
1416 If no $default is provided an empty string will be used instead.
1418 This method may be called as a class or object method.
1424 Returns a hash reference indicating the C<recommends> prerequisites
1425 that were passed to the C<new()> method.
1431 Returns a hash reference indicating the C<requires> prerequisites that
1432 were passed to the C<new()> method.
1434 =item rscan_dir($dir, $pattern)
1438 Uses C<File::Find> to traverse the directory C<$dir>, returning a
1439 reference to an array of entries matching C<$pattern>. C<$pattern>
1440 may either be a regular expression (using C<qr//> or just a plain
1441 string), or a reference to a subroutine that will return true for
1442 wanted entries. If C<$pattern> is not given, all entries will be
1447 # All the *.pm files in lib/
1448 $m->rscan_dir('lib', qr/\.pm$/)
1450 # All the files in blib/ that aren't *.html files
1451 $m->rscan_dir('blib', sub {-f $_ and not /\.html$/});
1453 # All the files in t/
1456 =item runtime_params()
1458 =item runtime_params($key)
1462 The C<runtime_params()> method stores the values passed on the command line
1463 for valid properties (that is, any command line options for which
1464 C<valid_property()> returns a true value). The value on the command line may
1465 override the default value for a property, as well as any value specified in a
1466 call to C<new()>. This allows you to programmatically tell if C<perl Build.PL>
1467 or any execution of C<./Build> had command line options specified that
1468 override valid properties.
1470 The C<runtime_params()> method is essentally a glorified read-only hash. With
1471 no arguments, C<runtime_params()> returns the entire hash of properties
1472 specified on the command line. With one argument, C<runtime_params($key)>
1473 returns the value associated with the given key.
1475 The lifetime of the C<runtime_params> data is for "a build" - that is, the
1476 C<runtime_params> hash is created when C<perl Build.PL> is run (or when the
1477 C<new()> method is called, if the Module::Build Perl API is being used instead
1478 of called from a shell), and lasts until C<perl Build.PL> is run again or the
1479 C<clean> action is run.
1481 =item script_files()
1485 Returns a hash reference whose keys are the perl script files to be
1486 installed, if any. This corresponds to the C<script_files> parameter to the
1487 C<new()> method. With an optional argument, this parameter may be set
1490 For backward compatibility, the C<scripts()> method does exactly the
1491 same thing as C<script_files()>. C<scripts()> is deprecated, but it
1492 will stay around for several versions to give people time to
1495 =item up_to_date($source_file, $derived_file)
1497 =item up_to_date(\@source_files, \@derived_files)
1501 This method can be used to compare a set of source files to a set of
1502 derived files. If any of the source files are newer than any of the
1503 derived files, it returns false. Additionally, if any of the derived
1504 files do not exist, it returns false. Otherwise it returns true.
1506 The arguments may be either a scalar or an array reference of file
1509 =item y_n($message, $default)
1513 Asks the user a yes/no question using C<prompt()> and returns true or
1514 false accordingly. The user will be asked the question repeatedly
1515 until they give an answer that looks like "yes" or "no".
1517 The first argument specifies the message to display to the user (for
1518 example, C<"Shall I invest your money for you?">), and the second
1519 argument specifies the default answer (for example, C<"y">).
1521 Note that the default is specified as a string like C<"y"> or C<"n">,
1522 and the return value is a Perl boolean value like 1 or 0. I thought
1523 about this for a while and this seemed like the most useful way to do
1526 This method may be called as a class or object method.
1531 =head2 Autogenerated Accessors
1533 In addition to the aforementioned methods, there are also some get/set
1534 accessor methods for the following properties:
1540 =item allow_mb_mismatch()
1554 =item build_elements()
1556 =item build_requires()
1558 =item build_script()
1566 =item create_makefile_pl()
1568 =item create_packlist()
1570 =item create_readme()
1580 =item include_dirs()
1582 =item install_base()
1584 =item install_sets()
1592 =item magic_number()
1606 =item original_prefix()
1618 =item prereq_action_types()
1624 =item recurse_into()
1626 =item recursive_test_files()
1643 Ken Williams <kwilliams@cpan.org>
1648 Copyright (c) 2001-2006 Ken Williams. All rights reserved.
1650 This library is free software; you can redistribute it and/or
1651 modify it under the same terms as Perl itself.
1656 perl(1), L<Module::Build>(3), L<Module::Build::Authoring>(3),
1657 L<Module::Build::Cookbook>(3), L<ExtUtils::MakeMaker>(3), L<YAML>(3)
1659 F<META.yml> Specification:
1660 L<http://module-build.sourceforge.net/META-spec-current.html>