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
722 Just like C<pm_files>, but used for specifying the set of C<.xs>
723 files in your distribution.
728 =item new_from_context(%args)
732 When called from a directory containing a F<Build.PL> script and a
733 F<META.yml> file (in other words, the base directory of a
734 distribution), this method will run the F<Build.PL> and return the
735 resulting C<Module::Build> object to the caller. Any key-value
736 arguments given to C<new_from_context()> are essentially like
737 command line arguments given to the F<Build.PL> script, so for example
738 you could pass C<< verbose => 1 >> to this method to turn on
745 You'll probably never call this method directly, it's only called from
746 the auto-generated C<Build> script. The C<new()> method is only
747 called once, when the user runs C<perl Build.PL>. Thereafter, when
748 the user runs C<Build test> or another action, the C<Module::Build>
749 object is created using the C<resume()> method to re-instantiate with
750 the settings given earlier to C<new()>.
756 This creates a new C<Module::Build> subclass on the fly, as described
757 in the L<Module::Build::Authoring/"SUBCLASSING"> section. The caller
758 must provide either a C<class> or C<code> parameter, or both. The
759 C<class> parameter indicates the name to use for the new subclass, and
760 defaults to C<MyModuleBuilder>. The C<code> parameter specifies Perl
761 code to use as the body of the subclass.
770 =item add_build_element($type)
774 Adds a new type of entry to the build process. Accepts a single
775 string specifying its type-name. There must also be a method defined
776 to process things of that type, e.g. if you add a build element called
777 C<'foo'>, then you must also define a method called
778 C<process_foo_files()>.
781 L<Module::Build::Cookbook/"Adding new file types to the build process">.
783 =item add_to_cleanup(@files)
787 You may call C<< $self->add_to_cleanup(@patterns) >> to tell
788 C<Module::Build> that certain files should be removed when the user
789 performs the C<Build clean> action. The arguments to the method are
790 patterns suitable for passing to Perl's C<glob()> function, specified
791 in either Unix format or the current machine's native format. It's
792 usually convenient to use Unix format when you hard-code the filenames
793 (e.g. in F<Build.PL>) and the native format when the names are
794 programmatically generated (e.g. in a testing script).
796 I decided to provide a dynamic method of the C<$build> object, rather
797 than just use a static list of files named in the F<Build.PL>, because
798 these static lists can get difficult to manage. I usually prefer to
799 keep the responsibility for registering temporary files close to the
800 code that creates them.
806 my $args_href = $build->args;
807 my %args = $build->args;
808 my $arg_value = $build->args($key);
809 $build->args($key, $value);
811 This method is the preferred interface for retrieving the arguments passed via
812 command line options to F<Build.PL> or F<Build>, minus the Module-Build
815 When called in in a scalar context with no arguments, this method returns a
816 reference to the hash storing all of the arguments; in an array context, it
817 returns the hash itself. When passed a single argument, it returns the value
818 stored in the args hash for that option key. When called with two arguments,
819 the second argument is assigned to the args hash under the key passed as the
822 =item autosplit_file($from, $to)
826 Invokes the C<AutoSplit> module on the C<$from> file, sending the
827 output to the C<lib/auto> directory inside C<$to>. C<$to> is
828 typically the C<blib/> directory.
834 Returns a string containing the root-level directory of this build,
835 i.e. where the C<Build.PL> script and the C<lib> directory can be
836 found. This is usually the same as the current working directory,
837 because the C<Build> script will C<chdir()> into this directory as
838 soon as it begins execution.
840 =item build_requires()
844 Returns a hash reference indicating the C<build_requires>
845 prerequisites that were passed to the C<new()> method.
847 =item check_installed_status($module, $version)
851 This method returns a hash reference indicating whether a version
852 dependency on a certain module is satisfied. The C<$module> argument
853 is given as a string like C<"Data::Dumper"> or C<"perl">, and the
854 C<$version> argument can take any of the forms described in L<requires>
855 above. This allows very fine-grained version checking.
857 The returned hash reference has the following structure:
860 ok => $whether_the_dependency_is_satisfied,
861 have => $version_already_installed,
862 need => $version_requested, # Same as incoming $version argument
863 message => $informative_error_message,
866 If no version of C<$module> is currently installed, the C<have> value
867 will be the string C<< "<none>" >>. Otherwise the C<have> value will
868 simply be the version of the installed module. Note that this means
869 that if C<$module> is installed but doesn't define a version number,
870 the C<have> value will be C<undef> - this is why we don't use C<undef>
871 for the case when C<$module> isn't installed at all.
873 This method may be called either as an object method
874 (C<< $build->check_installed_status($module, $version) >>)
876 (C<< Module::Build->check_installed_status($module, $version) >>).
878 =item check_installed_version($module, $version)
882 Like C<check_installed_status()>, but simply returns true or false
883 depending on whether module C<$module> satisfies the dependency
886 If the check succeeds, the return value is the actual version of
887 C<$module> installed on the system. This allows you to do the
890 my $installed = $build->check_installed_version('DBI', '1.15');
892 print "Congratulations, version $installed of DBI is installed.\n";
894 die "Sorry, you must install DBI.\n";
897 If the check fails, we return false and set C<$@> to an informative
900 If C<$version> is any non-true value (notably zero) and any version of
901 C<$module> is installed, we return true. In this case, if C<$module>
902 doesn't define a version, or if its version is zero, we return the
903 special value "0 but true", which is numerically zero, but logically
906 In general you might prefer to use C<check_installed_status> if you
907 need detailed information, or this method if you just need a yes/no
910 =item compare_versions($v1, $op, $v2)
914 Compares two module versions C<$v1> and C<$v2> using the operator
915 C<$op>, which should be one of Perl's numeric operators like C<!=> or
916 C<< >= >> or the like. We do at least a halfway-decent job of
917 handling versions that aren't strictly numeric, like C<0.27_02>, but
918 exotic stuff will likely cause problems.
920 In the future, the guts of this method might be replaced with a call
921 out to C<version.pm>.
927 Returns a hash reference containing the C<Config.pm> hash, including
928 any changes the author or user has specified. This is a reference to
929 the actual internal hash we use, so you probably shouldn't modify
932 =item config_data($name)
934 =item config_data($name => $value)
938 With a single argument, returns the value of the configuration
939 variable C<$name>. With two arguments, sets the given configuration
940 variable to the given value. The value may be any perl scalar that's
941 serializable with C<Data::Dumper>. For instance, if you write a
942 module that can use a MySQL or PostgreSQL back-end, you might create
943 configuration variables called C<mysql_connect> and
944 C<postgres_connect>, and set each to an array of connection parameters
945 for C<< DBI->connect() >>.
947 Configuration values set in this way using the Module::Build object
948 will be available for querying during the build/test process and after
949 installation via the generated C<...::ConfigData> module, as
950 C<< ...::ConfigData->config($name) >>.
952 The C<feature()> and C<config_data()> methods represent
953 Module::Build's main support for configuration of installed modules.
954 See also L<Module::Build::Authoring/"SAVING CONFIGURATION INFORMATION">.
960 Returns a hash reference indicating the C<conflicts> prerequisites
961 that were passed to the C<new()> method.
963 =item contains_pod($file)
967 [Deprecated] Please see L<Module::Build::ModuleInfo> instead.
969 Returns true if the given file appears to contain POD documentation.
970 Currently this checks whether the file has a line beginning with
971 '=pod', '=head', or '=item', but the exact semantics may change in the
974 =item copy_if_modified(%parameters)
978 Takes the file in the C<from> parameter and copies it to the file in
979 the C<to> parameter, or the directory in the C<to_dir> parameter, if
980 the file has changed since it was last copied (or if it doesn't exist
981 in the new location). By default the entire directory structure of
982 C<from> will be copied into C<to_dir>; an optional C<flatten>
983 parameter will copy into C<to_dir> without doing so.
985 Returns the path to the destination file, or C<undef> if nothing
988 Any directories that need to be created in order to perform the
989 copying will be automatically created.
991 The destination file is set to read-only. If the source file has the
992 executable bit set, then the destination file will be made executable.
994 =item create_build_script()
998 Creates an executable script called C<Build> in the current directory
999 that will be used to execute further user actions. This script is
1000 roughly analogous (in function, not in form) to the Makefile created
1001 by C<ExtUtils::MakeMaker>. This method also creates some temporary
1002 data in a directory called C<_build/>. Both of these will be removed
1003 when the C<realclean> action is performed.
1005 =item current_action()
1009 Returns the name of the currently-running action, such as "build" or
1010 "test". This action is not necessarily the action that was originally
1011 invoked by the user. For example, if the user invoked the "test"
1012 action, current_action() would initially return "test". However,
1013 action "test" depends on action "code", so current_action() will
1014 return "code" while that dependency is being executed. Once that
1015 action has completed, current_action() will again return "test".
1017 If you need to know the name of the original action invoked by the
1018 user, see L<invoked_action()> below.
1020 =item depends_on(@actions)
1024 Invokes the named action or list of actions in sequence. Using this
1025 method is preferred to calling the action explicitly because it
1026 performs some internal record-keeping, and it ensures that the same
1027 action is not invoked multiple times (note: in future versions of
1028 Module::Build it's conceivable that this run-only-once mechanism will
1029 be changed to something more intelligent).
1031 Note that the name of this method is something of a misnomer; it
1032 should really be called something like
1033 C<invoke_actions_unless_already_invoked()> or something, but for
1034 better or worse (perhaps better!) we were still thinking in
1035 C<make>-like dependency terms when we created this method.
1037 See also C<dispatch()>. The main distinction between the two is that
1038 C<depends_on()> is meant to call an action from inside another action,
1039 whereas C<dispatch()> is meant to set the very top action in motion.
1041 =item dir_contains($first_dir, $second_dir)
1045 Returns true if the first directory logically contains the second
1046 directory. This is just a convenience function because C<File::Spec>
1047 doesn't really provide an easy way to figure this out (but
1048 C<Path::Class> does...).
1050 =item dispatch($action, %args)
1054 Invokes the build action C<$action>. Optionally, a list of options
1055 and their values can be passed in. This is equivalent to invoking an
1056 action at the command line, passing in a list of options.
1058 Custom options that have not been registered must be passed in as a
1059 hash reference in a key named "args":
1061 $build->dispatch('foo', verbose => 1, args => { my_option => 'value' });
1063 This method is intended to be used to programmatically invoke build
1064 actions, e.g. by applications controlling Module::Build-based builds
1065 rather than by subclasses.
1067 See also C<depends_on()>. The main distinction between the two is that
1068 C<depends_on()> is meant to call an action from inside another action,
1069 whereas C<dispatch()> is meant to set the very top action in motion.
1075 Returns the name of the directory that will be created during the
1076 C<dist> action. The name is derived from the C<dist_name> and
1077 C<dist_version> properties.
1083 Returns the name of the current distribution, as passed to the
1084 C<new()> method in a C<dist_name> or modified C<module_name>
1087 =item dist_version()
1091 Returns the version of the current distribution, as determined by the
1092 C<new()> method from a C<dist_version>, C<dist_version_from>, or
1093 C<module_name> parameter.
1095 =item do_system($cmd, @args)
1099 This is a fairly simple wrapper around Perl's C<system()> built-in
1100 command. Given a command and an array of optional arguments, this
1101 method will print the command to C<STDOUT>, and then execute it using
1102 Perl's C<system()>. It returns true or false to indicate success or
1103 failure (the opposite of how C<system()> works, but more intuitive).
1105 Note that if you supply a single argument to C<do_system()>, it
1106 will/may be processed by the systems's shell, and any special
1107 characters will do their special things. If you supply multiple
1108 arguments, no shell will get involved and the command will be executed
1111 =item feature($name)
1113 =item feature($name => $value)
1117 With a single argument, returns true if the given feature is set.
1118 With two arguments, sets the given feature to the given boolean value.
1119 In this context, a "feature" is any optional functionality of an
1120 installed module. For instance, if you write a module that could
1121 optionally support a MySQL or PostgreSQL backend, you might create
1122 features called C<mysql_support> and C<postgres_support>, and set them
1123 to true/false depending on whether the user has the proper databases
1124 installed and configured.
1126 Features set in this way using the Module::Build object will be
1127 available for querying during the build/test process and after
1128 installation via the generated C<...::ConfigData> module, as
1129 C<< ...::ConfigData->feature($name) >>.
1131 The C<feature()> and C<config_data()> methods represent
1132 Module::Build's main support for configuration of installed modules.
1133 See also L<Module::Build::Authoring/"SAVING CONFIGURATION INFORMATION">.
1135 =item have_c_compiler()
1139 Returns true if the current system seems to have a working C compiler.
1140 We currently determine this by attempting to compile a simple C source
1141 file and reporting whether the attempt was successful.
1143 =item install_base_relpaths()
1145 =item install_base_relpaths($type)
1147 =item install_base_relpaths($type => $path)
1151 Set or retrieve the relative paths that are appended to
1152 C<install_base> for any installable element. This is useful if you
1153 want to set the relative install path for custom build elements.
1155 With no argument, it returns a reference to a hash containing all
1156 elements and their respective values. This hash should not be modified
1157 directly; use the multi-argument below form to change values.
1159 The single argument form returns the value associated with the
1162 The multi-argument form allows you to set the paths for element types.
1163 C<$value> must be a relative path using unix-like paths. (A series of
1164 directories seperated by slashes. Eg 'foo/bar'.) The return value is a
1165 localized path based on C<$value>.
1167 Assigning the value C<undef> to an element causes it to be removed.
1169 =item install_destination($type)
1173 Returns the directory in which items of type C<$type> (e.g. C<lib>,
1174 C<arch>, C<bin>, or anything else returned by the C<install_types()>
1175 method) will be installed during the C<install> action. Any settings
1176 for C<install_path>, C<install_base>, and C<prefix> are taken into
1177 account when determining the return value.
1179 =item install_path()
1181 =item install_path($type)
1183 =item install_path($type => $path)
1187 Set or retrieve paths for specific installable elements. This is
1188 useful when you want to examine any explicit install paths specified
1189 by the user on the command line, or if you want to set the install
1190 path for a specific installable element based on another attribute
1191 like C<install_base()>.
1193 With no argument, it returns a reference to a hash containing all
1194 elements and their respective values. This hash should not be modified
1195 directly; use the multi-argument below form to change values.
1197 The single argument form returns the value associated with the
1200 The multi-argument form allows you to set the paths for element types.
1201 The supplied C<$path> should be an absolute path to install elements
1202 of C<$type>. The return value is C<$path>.
1204 Assigning the value C<undef> to an element causes it to be removed.
1206 =item install_types()
1210 Returns a list of installable types that this build knows about.
1211 These types each correspond to the name of a directory in F<blib/>,
1212 and the list usually includes items such as C<lib>, C<arch>, C<bin>,
1213 C<script>, C<libdoc>, C<bindoc>, and if HTML documentation is to be
1214 built, C<libhtml> and C<binhtml>. Other user-defined types may also
1217 =item invoked_action()
1221 This is the name of the original action invoked by the user. This
1222 value is set when the user invokes F<Build.PL>, the F<Build> script,
1223 or programatically through the L<dispatch()> method. It does not
1224 change as sub-actions are executed as dependencies are evaluated.
1226 To get the name of the currently executing dependency, see
1227 L<current_action()> above.
1233 =item notes($key => $value)
1237 The C<notes()> value allows you to store your own persistent
1238 information about the build, and to share that information among
1239 different entities involved in the build. See the example in the
1240 C<current()> method.
1242 The C<notes()> method is essentally a glorified hash access. With no
1243 arguments, C<notes()> returns the entire hash of notes. With one argument,
1244 C<notes($key)> returns the value associated with the given key. With two
1245 arguments, C<notes($key, $value)> sets the value associated with the given key
1246 to C<$value> and returns the new value.
1248 The lifetime of the C<notes> data is for "a build" - that is, the
1249 C<notes> hash is created when C<perl Build.PL> is run (or when the
1250 C<new()> method is run, if the Module::Build Perl API is being used
1251 instead of called from a shell), and lasts until C<perl Build.PL> is
1252 run again or the C<clean> action is run.
1258 Returns a string containing the working directory that was in effect
1259 before the F<Build> script chdir()-ed into the C<base_dir>. This
1260 might be useful for writing wrapper tools that might need to chdir()
1267 If you're subclassing Module::Build and some code needs to alter its
1268 behavior based on the current platform, you may only need to know
1269 whether you're running on Windows, Unix, MacOS, VMS, etc., and not the
1270 fine-grained value of Perl's C<$^O> variable. The C<os_type()> method
1271 will return a string like C<Windows>, C<Unix>, C<MacOS>, C<VMS>, or
1272 whatever is appropriate. If you're running on an unknown platform, it
1273 will return C<undef> - there shouldn't be many unknown platforms
1276 =item prefix_relpaths()
1278 =item prefix_relpaths($installdirs)
1280 =item prefix_relpaths($installdirs, $type)
1282 =item prefix_relpaths($installdirs, $type => $path)
1286 Set or retrieve the relative paths that are appended to C<prefix> for
1287 any installable element. This is useful if you want to set the
1288 relative install path for custom build elements.
1290 With no argument, it returns a reference to a hash containing all
1291 elements and their respective values as defined by the current
1292 C<installdirs> setting.
1294 With a single argument, it returns a reference to a hash containing
1295 all elements and their respective values as defined by
1298 The hash returned by the above calls should not be modified directly;
1299 use the three-argument below form to change values.
1301 The two argument form returns the value associated with the
1304 The multi-argument form allows you to set the paths for element types.
1305 C<$value> must be a relative path using unix-like paths. (A series of
1306 directories seperated by slashes. Eg 'foo/bar'.) The return value is a
1307 localized path based on C<$value>.
1309 Assigning the value C<undef> to an element causes it to be removed.
1311 =item prepare_metadata()
1315 This method is provided for authors to override to customize the
1316 fields of F<META.yml>. It is passed a YAML::Node node object which can
1317 be modified as desired and then returned. E.g.
1319 package My::Builder;
1320 use base 'Module::Build';
1322 sub prepare_metadata {
1324 my $node = $self->SUPER::prepare_metadata( shift );
1325 $node->{custom_field} = 'foo';
1329 =item prereq_failures()
1333 Returns a data structure containing information about any failed
1334 prerequisites (of any of the types described above), or C<undef> if
1335 all prerequisites are met.
1337 The data structure returned is a hash reference. The top level keys
1338 are the type of prerequisite failed, one of "requires",
1339 "build_requires", "conflicts", or "recommends". The associated values
1340 are hash references whose keys are the names of required (or
1341 conflicting) modules. The associated values of those are hash
1342 references indicating some information about the failure. For example:
1347 message => 'Version 0.42 is installed, but we need version 0.59',
1355 message => 'Prerequisite Foo isn't installed',
1358 This hash has the same structure as the hash returned by the
1359 C<check_installed_status()> method, except that in the case of
1360 "conflicts" dependencies we change the "need" key to "conflicts" and
1361 construct a proper message.
1365 # Check a required dependency on Foo::Bar
1366 if ( $build->prereq_failures->{requires}{Foo::Bar} ) { ...
1368 # Check whether there were any failures
1369 if ( $build->prereq_failures ) { ...
1371 # Show messages for all failures
1372 my $failures = $build->prereq_failures;
1373 while (my ($type, $list) = each %$failures) {
1374 while (my ($name, $hash) = each %$list) {
1375 print "Failure for $name: $hash->{message}\n";
1379 =item prereq_report()
1383 Returns a human-readable (table-form) string showing all
1384 prerequisites, the versions required, and the versions actually
1385 installed. This can be useful for reviewing the configuration of your
1386 system prior to a build, or when compiling data to send for a bug
1387 report. The C<prereq_report> action is just a thin wrapper around the
1388 C<prereq_report()> method.
1390 =item prompt($message, $default)
1394 Asks the user a question and returns their response as a string. The
1395 first argument specifies the message to display to the user (for
1396 example, C<"Where do you keep your money?">). The second argument,
1397 which is optional, specifies a default answer (for example,
1398 C<"wallet">). The user will be asked the question once.
1400 If C<prompt()> detects that it is not running interactively and there
1401 is nothing on STDIN or if the PERL_MM_USE_DEFAULT environment variable
1402 is set to true, the $default will be used without prompting. This
1403 prevents automated processes from blocking on user input.
1405 If no $default is provided an empty string will be used instead.
1407 This method may be called as a class or object method.
1413 Returns a hash reference indicating the C<recommends> prerequisites
1414 that were passed to the C<new()> method.
1420 Returns a hash reference indicating the C<requires> prerequisites that
1421 were passed to the C<new()> method.
1423 =item rscan_dir($dir, $pattern)
1427 Uses C<File::Find> to traverse the directory C<$dir>, returning a
1428 reference to an array of entries matching C<$pattern>. C<$pattern>
1429 may either be a regular expression (using C<qr//> or just a plain
1430 string), or a reference to a subroutine that will return true for
1431 wanted entries. If C<$pattern> is not given, all entries will be
1436 # All the *.pm files in lib/
1437 $m->rscan_dir('lib', qr/\.pm$/)
1439 # All the files in blib/ that aren't *.html files
1440 $m->rscan_dir('blib', sub {-f $_ and not /\.html$/});
1442 # All the files in t/
1445 =item runtime_params()
1447 =item runtime_params($key)
1451 The C<runtime_params()> method stores the values passed on the command line
1452 for valid properties (that is, any command line options for which
1453 C<valid_property()> returns a true value). The value on the command line may
1454 override the default value for a property, as well as any value specified in a
1455 call to C<new()>. This allows you to programmatically tell if C<perl Build.PL>
1456 or any execution of C<./Build> had command line options specified that
1457 override valid properties.
1459 The C<runtime_params()> method is essentally a glorified read-only hash. With
1460 no arguments, C<runtime_params()> returns the entire hash of properties
1461 specified on the command line. With one argument, C<runtime_params($key)>
1462 returns the value associated with the given key.
1464 The lifetime of the C<runtime_params> data is for "a build" - that is, the
1465 C<runtime_params> hash is created when C<perl Build.PL> is run (or when the
1466 C<new()> method is called, if the Module::Build Perl API is being used instead
1467 of called from a shell), and lasts until C<perl Build.PL> is run again or the
1468 C<clean> action is run.
1470 =item script_files()
1474 Returns a hash reference whose keys are the perl script files to be
1475 installed, if any. This corresponds to the C<script_files> parameter to the
1476 C<new()> method. With an optional argument, this parameter may be set
1479 For backward compatibility, the C<scripts()> method does exactly the
1480 same thing as C<script_files()>. C<scripts()> is deprecated, but it
1481 will stay around for several versions to give people time to
1484 =item up_to_date($source_file, $derived_file)
1486 =item up_to_date(\@source_files, \@derived_files)
1490 This method can be used to compare a set of source files to a set of
1491 derived files. If any of the source files are newer than any of the
1492 derived files, it returns false. Additionally, if any of the derived
1493 files do not exist, it returns false. Otherwise it returns true.
1495 The arguments may be either a scalar or an array reference of file
1498 =item y_n($message, $default)
1502 Asks the user a yes/no question using C<prompt()> and returns true or
1503 false accordingly. The user will be asked the question repeatedly
1504 until they give an answer that looks like "yes" or "no".
1506 The first argument specifies the message to display to the user (for
1507 example, C<"Shall I invest your money for you?">), and the second
1508 argument specifies the default answer (for example, C<"y">).
1510 Note that the default is specified as a string like C<"y"> or C<"n">,
1511 and the return value is a Perl boolean value like 1 or 0. I thought
1512 about this for a while and this seemed like the most useful way to do
1515 This method may be called as a class or object method.
1520 =head2 Autogenerated Accessors
1522 In addition to the aforementioned methods, there are also some get/set
1523 accessor methods for the following properties:
1529 =item allow_mb_mismatch()
1543 =item build_elements()
1545 =item build_requires()
1547 =item build_script()
1557 =item create_makefile_pl()
1559 =item create_packlist()
1561 =item create_readme()
1571 =item include_dirs()
1573 =item install_base()
1575 =item install_sets()
1583 =item magic_number()
1597 =item original_prefix()
1609 =item prereq_action_types()
1615 =item recurse_into()
1617 =item recursive_test_files()
1634 Ken Williams <kwilliams@cpan.org>
1639 Copyright (c) 2001-2006 Ken Williams. All rights reserved.
1641 This library is free software; you can redistribute it and/or
1642 modify it under the same terms as Perl itself.
1647 perl(1), L<Module::Build>(3), L<Module::Build::Authoring>(3),
1648 L<Module::Build::Cookbook>(3), L<ExtUtils::MakeMaker>(3), L<YAML>(3)
1650 F<META.yml> Specification:
1651 L<http://module-build.sourceforge.net/META-spec-v1.2.html>