Module::Build::API
Module::Build::API(3)User Contributed Perl DocumentationModule::Build::API(3)
NAME
Module::Build::API - API Reference for Module Authors
DESCRIPTION
I list here some of the most important methods in "Module::Build".
Normally you won’t need to deal with these methods unless you want to
subclass "Module::Build". But since one of the reasons I created this
module in the first place was so that subclassing is possible (and
easy), I will certainly write more docs as the interface stabilizes.
CONSTRUCTORS
current()
[version 0.20]
This method returns a reasonable facsimile of the currently-exe-
cuting "Module::Build" object representing the current build. You
can use this object to query its "notes()" method, inquire about
installed modules, and so on. This is a great way to share infor-
mation between different parts of your build process. For
instance, you can ask the user a question during "perl Build.PL",
then use their answer during a regression test:
# In Build.PL:
my $color = $build->prompt("What is your favorite color?");
$build->notes(color => $color);
# In t/colortest.t:
use Module::Build;
my $build = Module::Build->current;
my $color = $build->notes(’color’);
...
The way the "current()" method is currently implemented, there may
be slight differences between the $build object in Build.PL and
the one in "t/colortest.t". It is our goal to minimize these dif-
ferences in future releases of Module::Build, so please report any
anomalies you find.
One important caveat: in its current implementation, "current()"
will NOT work correctly if you have changed out of the directory
that "Module::Build" was invoked from.
new()
[version 0.03]
Creates a new Module::Build object. Arguments to the new() method
are listed below. Most arguments are optional, but you must pro-
vide either the "module_name" argument, or "dist_name" and one of
"dist_version" or "dist_version_from". In other words, you must
provide enough information to determine both a distribution name
and version.
add_to_cleanup
[version 0.19]
An array reference of files to be cleaned up when the "clean"
action is performed. See also the add_to_cleanup() method.
auto_features
[version 0.26]
This parameter supports the setting of features (see "fea-
ture($name)") automatically based on a set of prerequisites.
For instance, for a module that could optionally use either
MySQL or PostgreSQL databases, you might use "auto_features"
like this:
my $build = Module::Build->new
(
...other stuff here...
auto_features => {
pg_support => {
description => "Interface with Postgres databases",
requires => { ’DBD::Pg’ => 23.3,
’DateTime::Format::Pg’ => 0 },
},
mysql_support => {
description => "Interface with MySQL databases",
requires => { ’DBD::mysql’ => 17.9,
’DateTime::Format::MySQL’ => 0 },
},
}
);
For each feature named, the required prerequisites will be
checked, and if there are no failures, the feature will be
enabled (set to 1). Otherwise the failures will be displayed
to the user and the feature will be disabled (set to 0).
See the documentation for "requires" for the details of how
requirements can be specified.
autosplit
[version 0.04]
An optional "autosplit" argument specifies a file which should
be run through the AutoSplit::autosplit() function. If multi-
ple files should be split, the argument may be given as an
array of the files to split.
In general I don’t consider autosplitting a great idea,
because it’s not always clear that autosplitting achieves its
intended performance benefits. It may even harm performance
in environments like mod_perl, where as much as possible of a
module’s code should be loaded during startup.
build_class
[version 0.28]
The Module::Build class or subclass to use in the build
script. Defaults to "Module::Build" or the class name passed
to or created by a call to "subclass()". This property is
useful if you’re writing a custom Module::Build subclass and
have a bootstrapping problem--that is, your subclass requires
modules that may not be installed when "perl Build.PL" is exe-
cuted, but you’ve listed in "build_requires" so that they
should be available when "./Build" is executed.
build_requires
[version 0.07]
Modules listed in this section are necessary to build and
install the given module, but are not necessary for regular
usage of it. This is actually an important distinction - it
allows for tighter control over the body of installed modules,
and facilitates correct dependency checking on binary/packaged
distributions of the module.
See the documentation for "PREREQUISITES" in Mod-
ule::Build::Authoring for the details of how requirements can
be specified.
create_packlist
[version 0.28]
If true, this parameter tells Module::Build to create a .pack-
list file during the "install" action, just like ExtU-
tils::MakeMaker does. The file is created in a subdirectory
of the "arch" installation location. It is used by some other
tools (CPAN, CPANPLUS, etc.) for determining what files are
part of an install.
The default value is true. This parameter was introduced in
Module::Build version 0.2609; previously no packlists were
ever created by Module::Build.
c_source
[version 0.04]
An optional "c_source" argument specifies a directory which
contains C source files that the rest of the build may depend
on. Any ".c" files in the directory will be compiled to
object files. The directory will be added to the search path
during the compilation and linking phases of any C or XS
files.
conflicts
[version 0.07]
Modules listed in this section conflict in some serious way
with the given module. "Module::Build" (or some higher-level
tool) will refuse to install the given module if the given
module/version is also installed.
See the documentation for "PREREQUISITES" in Mod-
ule::Build::Authoring for the details of how requirements can
be specified.
create_makefile_pl
[version 0.19]
This parameter lets you use Module::Build::Compat during the
"distdir" (or "dist") action to automatically create a Make-
file.PL for compatibility with ExtUtils::MakeMaker. The
parameter’s value should be one of the styles named in the
Module::Build::Compat documentation.
create_readme
[version 0.22]
This parameter tells Module::Build to automatically create a
README file at the top level of your distribution. Currently
it will simply use "Pod::Text" (or "Pod::Readme" if it’s
installed) on the file indicated by "dist_version_from" and
put the result in the README file. This is by no means the
only recommended style for writing a README, but it seems to
be one common one used on the CPAN.
If you generate a README in this way, it’s probably a good
idea to create a separate INSTALL file if that information
isn’t in the generated README.
dist_abstract
[version 0.20]
This should be a short description of the distribution. This
is used when generating metadata for META.yml and PPD files.
If it is not given then "Module::Build" looks in the POD of
the module from which it gets the distribution’s version. If
it finds a POD section marked "=head1 NAME", then it looks for
the first line matching "\s+-\s+(.+)", and uses the captured
text as the abstract.
dist_author
[version 0.20]
This should be something like "John Doe <jdoe@example.com>",
or if there are multiple authors, an anonymous array of
strings may be specified. This is used when generating meta-
data for META.yml and PPD files. If this is not specified,
then "Module::Build" looks at the module from which it gets
the distribution’s version. If it finds a POD section marked
"=head1 AUTHOR", then it uses the contents of this section.
dist_name
[version 0.11]
Specifies the name for this distribution. Most authors won’t
need to set this directly, they can use "module_name" to set
"dist_name" to a reasonable default. However, some agglomera-
tive distributions like "libwww-perl" or "bioperl" have names
that don’t correspond directly to a module name, so
"dist_name" can be set independently.
dist_version
[version 0.11]
Specifies a version number for the distribution. See "mod-
ule_name" or "dist_version_from" for ways to have this set
automatically from a $VERSION variable in a module. One way
or another, a version number needs to be set.
dist_version_from
[version 0.11]
Specifies a file to look for the distribution version in.
Most authors won’t need to set this directly, they can use
"module_name" to set it to a reasonable default.
The version is extracted from the specified file according to
the same rules as ExtUtils::MakeMaker and "CPAN.pm". It
involves finding the first line that matches the regular
expression
/([\$*])(([\w\:\’]*)\bVERSION)\b.*\=/
eval()-ing that line, then checking the value of the $VERSION
variable. Quite ugly, really, but all the modules on CPAN
depend on this process, so there’s no real opportunity to
change to something better.
If the target file of "dist_version_from" contains more than
one package declaration, the version returned will be the one
matching the configured "module_name".
dynamic_config
[version 0.07]
A boolean flag indicating whether the Build.PL file must be
executed, or whether this module can be built, tested and
installed solely from consulting its metadata file. The main
reason to set this to a true value is that your module
performs some dynamic configuration as part of its
build/install process. If the flag is omitted, the META.yml
spec says that installation tools should treat it as 1 (true),
because this is a safer way to behave.
Currently "Module::Build" doesn’t actually do anything with
this flag - it’s up to higher-level tools like "CPAN.pm" to do
something useful with it. It can potentially bring lots of
security, packaging, and convenience improvements.
extra_compiler_flags
extra_linker_flags
[version 0.19]
These parameters can contain array references (or strings, in
which case they will be split into arrays) to pass through to
the compiler and linker phases when compiling/linking C code.
For example, to tell the compiler that your code is C++, you
might do:
my $build = Module::Build->new
(
module_name => ’Foo::Bar’,
extra_compiler_flags => [’-x’, ’c++’],
);
To link your XS code against glib you might write something
like:
my $build = Module::Build->new
(
module_name => ’Foo::Bar’,
dynamic_config => 1,
extra_compiler_flags => scalar ‘glib-config --cflags‘,
extra_linker_flags => scalar ‘glib-config --libs‘,
);
get_options
[version 0.26]
You can pass arbitrary command line options to Build.PL or
Build, and they will be stored in the Module::Build object and
can be accessed via the "args()" method. However, sometimes
you want more flexibility out of your argument processing than
this allows. In such cases, use the "get_options" parameter
to pass in a hash reference of argument specifications, and
the list of arguments to Build.PL or Build will be processed
according to those specifications before they’re passed on to
"Module::Build"’s own argument processing.
The supported option specification hash keys are:
type
The type of option. The types are those supported by
Getopt::Long; consult its documentation for a complete
list. Typical types are "=s" for strings, "+" for addi-
tive options, and "!" for negatable options. If the type
is not specified, it will be considered a boolean, i.e. no
argument is taken and a value of 1 will be assigned when
the option is encountered.
store
A reference to a scalar in which to store the value passed
to the option. If not specified, the value will be stored
under the option name in the hash returned by the "args()"
method.
default
A default value for the option. If no default value is
specified and no option is passed, then the option key
will not exist in the hash returned by "args()".
You can combine references to your own variables or subrou-
tines with unreferenced specifications, for which the result
will also be stored in the hash returned by "args()". For
example:
my $loud = 0;
my $build = Module::Build->new
(
module_name => ’Foo::Bar’,
get_options => {
loud => { store => \$loud },
dbd => { type => ’=s’ },
quantity => { type => ’+’ },
}
);
print STDERR "HEY, ARE YOU LISTENING??\n" if $loud;
print "We’ll use the ", $build->args(’dbd’), " DBI driver\n";
print "Are you sure you want that many?\n"
if $build->args(’quantity’) > 2;
The arguments for such a specification can be called like so:
perl Build.PL --loud --dbd=DBD::pg --quantity --quantity --quantity
WARNING: Any option specifications that conflict with Mod-
ule::Build’s own options (defined by its properties) will
throw an exception.
Consult the Getopt::Long documentation for details on its
usage.
include_dirs
[version 0.24]
Specifies any additional directories in which to search for C
header files. May be given as a string indicating a single
directory, or as a list reference indicating multiple directo-
ries.
install_path
[version 0.19]
You can set paths for individual installable elements by using
the "install_path" parameter:
my $build = Module::Build->new
(
...other stuff here...
install_path => {
lib => ’/foo/lib’,
arch => ’/foo/lib/arch’,
}
);
installdirs
[version 0.19]
Determines where files are installed within the normal perl
hierarchy as determined by Config.pm. Valid values are:
"core", "site", "vendor". The default is "site". See
"INSTALL PATHS" in Module::Build
license
[version 0.07]
Specifies the licensing terms of your distribution. Valid
options include:
apache
The distribution is licensed under the Apache Software
License (<http://opensource.org/licenses/apachepl.php>).
artistic
The distribution is licensed under the Artistic License,
as specified by the Artistic file in the standard Perl
distribution.
artistic_2
The distribution is licensed under the Artistic 2.0
License (<http://opensource.org/licenses/artis-
tic-license-2.0.php>.)
bsd The distribution is licensed under the BSD License
(<http://www.opensource.org/licenses/bsd-license.php>).
gpl The distribution is licensed under the terms of the GNU
General Public License (<http://www.open-
source.org/licenses/gpl-license.php>).
lgpl
The distribution is licensed under the terms of the GNU
Lesser General Public License (<http://www.open-
source.org/licenses/lgpl-license.php>).
mit The distribution is licensed under the MIT License
(<http://opensource.org/licenses/mit-license.php>).
mozilla
The distribution is licensed under the Mozilla Public
License. (<http://opensource.org/licenses/mozilla1.0.php>
or <http://opensource.org/licenses/mozilla1.1.php>)
open_source
The distribution is licensed under some other Open Source
Initiative-approved license listed at <http://www.open-
source.org/licenses/>.
perl
The distribution may be copied and redistributed under the
same terms as Perl itself (this is by far the most common
licensing option for modules on CPAN). This is a dual
license, in which the user may choose between either the
GPL or the Artistic license.
restrictive
The distribution may not be redistributed without special
permission from the author and/or copyright holder.
unrestricted
The distribution is licensed under a license that is not
approved by www.opensource.org but that allows distribu-
tion without restrictions.
Note that you must still include the terms of your license in
your documentation - this field only lets automated tools fig-
ure out your licensing restrictions. Humans still need some-
thing to read. If you choose to provide this field, you
should make sure that you keep it in sync with your written
documentation if you ever change your licensing terms.
You may also use a license type of "unknown" if you don’t wish
to specify your terms in the metadata.
It is a fatal error to use a license other than the ones men-
tioned above. This is not because I wish to impose licensing
terms on you - please let me know if you would like another
license option to be added to the list. I just started out
with a small set of licenses to keep things simple, figuring
I’d let people with actual working knowledge in this area tell
me what to do. So if that’s you, drop me a line.
meta_add
[version 0.28]
A hash of key/value pairs that should be added to the META.yml
file during the "distmeta" action. Any existing entries with
the same names will be overridden.
See the "MODULE METADATA" section for details.
meta_merge
[version 0.28]
A hash of key/value pairs that should be merged into the
META.yml file during the "distmeta" action. Any existing
entries with the same names will be overridden.
The only difference between "meta_add" and "meta_merge" is
their behavior on hash-valued and array-valued entries:
"meta_add" will completely blow away the existing hash or
array value, but "meta_merge" will merge the supplied data
into the existing hash or array value.
See the "MODULE METADATA" section for details.
module_name
[version 0.03]
The "module_name" is a shortcut for setting default values of
"dist_name" and "dist_version_from", reflecting the fact that
the majority of CPAN distributions are centered around one
"main" module. For instance, if you set "module_name" to
"Foo::Bar", then "dist_name" will default to "Foo-Bar" and
"dist_version_from" will default to "lib/Foo/Bar.pm".
"dist_version_from" will in turn be used to set "dist_ver-
sion".
Setting "module_name" won’t override a "dist_*" parameter you
specify explicitly.
PL_files
[version 0.06]
An optional parameter specifying a set of ".PL" files in your
distribution. These will be run as Perl scripts prior to pro-
cessing the rest of the files in your distribution. They are
usually used as templates for creating other files dynami-
cally, so that a file like "lib/Foo/Bar.pm.PL" might create
the file "lib/Foo/Bar.pm".
The files are specified with the ".PL" files as hash keys, and
the file(s) they generate as hash values, like so:
my $build = Module::Build->new
(
module_name => ’Foo::Bar’,
...
PL_files => { ’lib/Foo/Bar.pm.PL’ => ’lib/Foo/Bar.pm’ },
);
Note that the path specifications are always given in Unix-
like format, not in the style of the local system.
If your ".PL" scripts don’t create any files, or if they cre-
ate files with unexpected names, or even if they create multi-
ple files, you can indicate that so that Module::Build can
properly handle these created files:
PL_files => {
’lib/Foo/Bar.pm.PL’ => ’lib/Foo/Bar.pm’,
’lib/something.PL’ => [’/lib/something’, ’/lib/else’],
’lib/funny.PL’ => [],
}
pm_files
[version 0.19]
An optional parameter specifying the set of ".pm" files in
this distribution, specified as a hash reference whose keys
are the files’ locations in the distributions, and whose val-
ues are their logical locations based on their package name,
i.e. where they would be found in a "normal" Mod-
ule::Build-style distribution. This parameter is mainly
intended to support alternative layouts of files.
For instance, if you have an old-style MakeMaker distribution
for a module called "Foo::Bar" and a Bar.pm file at the top
level of the distribution, you could specify your layout in
your "Build.PL" like this:
my $build = Module::Build->new
(
module_name => ’Foo::Bar’,
...
pm_files => { ’Bar.pm’ => ’lib/Foo/Bar.pm’ },
);
Note that the values should include "lib/", because this is
where they would be found in a "normal" Module::Build-style
distribution.
Note also that the path specifications are always given in
Unix-like format, not in the style of the local system.
pod_files
[version 0.19]
Just like "pm_files", but used for specifying the set of
".pod" files in your distribution.
recommends
[version 0.08]
This is just like the "requires" argument, except that modules
listed in this section aren’t essential, just a good idea.
We’ll just print a friendly warning if one of these modules
aren’t found, but we’ll continue running.
If a module is recommended but not required, all tests should
still pass if the module isn’t installed. This may mean that
some tests may be skipped if recommended dependencies aren’t
present.
Automated tools like CPAN.pm should inform the user when rec-
ommended modules aren’t installed, and it should offer to
install them if it wants to be helpful.
See the documentation for "PREREQUISITES" in Mod-
ule::Build::Authoring for the details of how requirements can
be specified.
recursive_test_files
[version 0.28]
Normally, "Module::Build" does not search subdirectories when
looking for tests to run. When this options is set it will
search recursively in all subdirectories of the standard ’t’
test directory.
requires
[version 0.07]
An optional "requires" argument specifies any module prerequi-
sites that the current module depends on.
One note: currently "Module::Build" doesn’t actually require
the user to have dependencies installed, it just strongly
urges. In the future we may require it. There’s also a "rec-
ommends" section for things that aren’t absolutely required.
Automated tools like CPAN.pm should refuse to install a module
if one of its dependencies isn’t satisfied, unless a "force"
command is given by the user. If the tools are helpful, they
should also offer to install the dependencies.
A synonym for "requires" is "prereq", to help succour people
transitioning from "ExtUtils::MakeMaker". The "requires" term
is preferred, but the "prereq" term will remain valid in
future distributions.
See the documentation for "PREREQUISITES" in Mod-
ule::Build::Authoring for the details of how requirements can
be specified.
script_files
[version 0.18]
An optional parameter specifying a set of files that should be
installed as executable Perl scripts when the module is
installed. May be given as an array reference of the files,
as a hash reference whose keys are the files (and whose values
will currently be ignored), as a string giving the name of a
directory in which to find scripts, or as a string giving the
name of a single script file.
The default is to install any scripts found in a bin directory
at the top level of the distribution.
For backward compatibility, you may use the parameter
"scripts" instead of "script_files". Please consider this
usage deprecated, though it will continue to exist for several
version releases.
sign
[version 0.16]
If a true value is specified for this parameter, Module::Sig-
nature will be used (via the ’distsign’ action) to create a
SIGNATURE file for your distribution during the ’distdir’
action, and to add the SIGNATURE file to the MANIFEST (there-
fore, don’t add it yourself).
The default value is false. In the future, the default may
change to true if you have "Module::Signature" installed on
your system.
test_files
[version 0.23]
An optional parameter specifying a set of files that should be
used as "Test::Harness"-style regression tests to be run dur-
ing the "test" action. May be given as an array reference of
the files, or as a hash reference whose keys are the files
(and whose values will currently be ignored). If the argument
is given as a single string (not in an array reference), that
string will be treated as a "glob()" pattern specifying the
files to use.
The default is to look for a test.pl script in the top-level
directory of the distribution, and any files matching the glob
pattern "*.t" in the t/ subdirectory. If the "recur-
sive_test_files" property is true, then the "t/" directory
will be scanned recursively for "*.t" files.
use_tap_harness
[version 0.2808_03]
An optional parameter indicating whether or not to use
TAP::Harness for testing rather than Test::Harness. Defaults
to false. If set to true, you must therefore be sure to add
TAP::Harness as a requirement for your module in
"build_requires". Implicitly set to a true value if "tap_har-
ness_args" is specified.
tap_harness_args
[version 0.2808_03]
An optional parameter specifying parameters to be passed to
TAP::Harness when running tests. Must be given as a hash ref-
erence of parameters; see the TAP::Harness documentation for
details. Note that specifying this parameter will implicitly
set "use_tap_harness" to a true value. You must therefore be
sure to add TAP::Harness as a requirement for your module in
"build_requires".
xs_files
[version 0.19]
Just like "pm_files", but used for specifying the set of ".xs"
files in your distribution.
new_from_context(%args)
[version 0.28]
When called from a directory containing a Build.PL script and a
META.yml file (in other words, the base directory of a distribu-
tion), this method will run the Build.PL and return the resulting
"Module::Build" object to the caller. Any key-value arguments
given to "new_from_context()" are essentially like command line
arguments given to the Build.PL script, so for example you could
pass "verbose => 1" to this method to turn on verbosity.
resume()
[version 0.03]
You’ll probably never call this method directly, it’s only called
from the auto-generated "Build" script. The "new()" method is
only called once, when the user runs "perl Build.PL". Thereafter,
when the user runs "Build test" or another action, the "Mod-
ule::Build" object is created using the "resume()" method to re-
instantiate with the settings given earlier to "new()".
subclass()
[version 0.06]
This creates a new "Module::Build" subclass on the fly, as
described in the "SUBCLASSING" in Module::Build::Authoring sec-
tion. The caller must provide either a "class" or "code" parame-
ter, or both. The "class" parameter indicates the name to use for
the new subclass, and defaults to "MyModuleBuilder". The "code"
parameter specifies Perl code to use as the body of the subclass.
add_property
[version 0.31]
package ’My::Build’;
use base ’Module::Build’;
__PACKAGE__->add_property( ’pedantic’ );
__PACKAGE__->add_property( answer => 42 );
__PACKAGE__->add_property(
’epoch’,
default => sub { time },
check => sub {
return 1 if /^\d+$/;
shift->property_error( "’$_’ is not an epoch time" );
return 0;
},
);
Adds a property to a Module::Build class. Properties are those
attributes of a Module::Build object which can be passed to the
constructor and which have accessors to get and set them. All of
the core properties, such as "module_name" and "license", are
defined using this class method.
The first argument to "add_property()" is always the name of the
property. The second argument can be either a default value for
the property, or a list of key/value pairs. The supported keys
are:
"default"
The default value. May optionally be specified as a code ref-
erence, in which case the return value from the execution of
the code reference will be used. If you need the default to
be a code reference, just use a code reference to return it,
e.g.:
default => sub { sub { ... } },
"check"
A code reference that checks that a value specified for the
property is valid. During the execution of the code refer-
ence, the new value will be included in the $_ variable. If
the value is correct, the "check" code reference should return
true. If the value is not correct, it sends an error message
to "property_error()" and returns false.
When this method is called, a new property will be installed in
the Module::Build class, and an accessor will be built to allow
the property to be get or set on the build object.
print $build->pedantic, $/;
$build->pedantic(0);
If the default value is a hash reference, this generetes a spe-
cial-case accessor method, wherein individual key/value pairs may
be set or fetched:
print "stuff{foo} is: ", $build->stuff( ’foo’ ), $/;
$build->stuff( foo => ’bar’ );
print $build->stuff( ’foo’ ), $/; # Outputs "bar"
Of course, you can still set the entire hash reference at once, as
well:
$build->stuff( { foo => ’bar’, baz => ’yo’ } );
In either case, if a "check" has been specified for the property,
it will be applied to the entire hash. So the check code reference
should look something like:
check => sub {
return 1 if defined $_ && exists $_->{foo};
shift->property_error(qq{Property "stuff" needs "foo"});
return 0;
},
property_error
[version 0.31]
METHODS
add_build_element($type)
[version 0.26]
Adds a new type of entry to the build process. Accepts a single
string specifying its type-name. There must also be a method
defined to process things of that type, e.g. if you add a build
element called ’foo’, then you must also define a method called
"process_foo_files()".
See also "Adding new file types to the build process" in Mod-
ule::Build::Cookbook.
add_to_cleanup(@files)
[version 0.03]
You may call "$self->add_to_cleanup(@patterns)" to tell "Mod-
ule::Build" that certain files should be removed when the user
performs the "Build clean" action. The arguments to the method
are patterns suitable for passing to Perl’s "glob()" function,
specified in either Unix format or the current machine’s native
format. It’s usually convenient to use Unix format when you hard-
code the filenames (e.g. in Build.PL) and the native format when
the names are programmatically generated (e.g. in a testing
script).
I decided to provide a dynamic method of the $build object, rather
than just use a static list of files named in the Build.PL,
because these static lists can get difficult to manage. I usually
prefer to keep the responsibility for registering temporary files
close to the code that creates them.
args()
[version 0.26]
my $args_href = $build->args;
my %args = $build->args;
my $arg_value = $build->args($key);
$build->args($key, $value);
This method is the preferred interface for retrieving the argu-
ments passed via command line options to Build.PL or Build, minus
the Module-Build specific options.
When called in in a scalar context with no arguments, this method
returns a reference to the hash storing all of the arguments; in
an array context, it returns the hash itself. When passed a sin-
gle argument, it returns the value stored in the args hash for
that option key. When called with two arguments, the second argu-
ment is assigned to the args hash under the key passed as the
first argument.
autosplit_file($from, $to)
[version 0.28]
Invokes the AutoSplit module on the $from file, sending the output
to the "lib/auto" directory inside $to. $to is typically the
"blib/" directory.
base_dir()
[version 0.14]
Returns a string containing the root-level directory of this
build, i.e. where the "Build.PL" script and the "lib" directory
can be found. This is usually the same as the current working
directory, because the "Build" script will "chdir()" into this
directory as soon as it begins execution.
build_requires()
[version 0.21]
Returns a hash reference indicating the "build_requires" prerequi-
sites that were passed to the "new()" method.
cbuilder()
[version 0.2809]
Returns the internal ExtUtils::CBuilder object that can be used
for compiling & linking C code. If no such object is available
(e.g. if the system has no compiler installed) an exception will
be thrown.
check_installed_status($module, $version)
[version 0.11]
This method returns a hash reference indicating whether a version
dependency on a certain module is satisfied. The $module argument
is given as a string like "Data::Dumper" or "perl", and the $ver-
sion argument can take any of the forms described in "requires"
above. This allows very fine-grained version checking.
The returned hash reference has the following structure:
{
ok => $whether_the_dependency_is_satisfied,
have => $version_already_installed,
need => $version_requested, # Same as incoming $version argument
message => $informative_error_message,
}
If no version of $module is currently installed, the "have" value
will be the string "<none>". Otherwise the "have" value will sim-
ply be the version of the installed module. Note that this means
that if $module is installed but doesn’t define a version number,
the "have" value will be "undef" - this is why we don’t use
"undef" for the case when $module isn’t installed at all.
This method may be called either as an object method
("$build->check_installed_status($module, $version)") or as a
class method ("Module::Build->check_installed_status($module,
$version)").
check_installed_version($module, $version)
[version 0.05]
Like check_installed_status(), but simply returns true or false
depending on whether module $module satisfies the dependency $ver-
sion.
If the check succeeds, the return value is the actual version of
$module installed on the system. This allows you to do the fol-
lowing:
my $installed = $build->check_installed_version(’DBI’, ’1.15’);
if ($installed) {
print "Congratulations, version $installed of DBI is installed.\n";
} else {
die "Sorry, you must install DBI.\n";
}
If the check fails, we return false and set $@ to an informative
error message.
If $version is any non-true value (notably zero) and any version
of $module is installed, we return true. In this case, if $module
doesn’t define a version, or if its version is zero, we return the
special value "0 but true", which is numerically zero, but logi-
cally true.
In general you might prefer to use "check_installed_status" if you
need detailed information, or this method if you just need a
yes/no answer.
compare_versions($v1, $op, $v2)
[version 0.28]
Compares two module versions $v1 and $v2 using the operator $op,
which should be one of Perl’s numeric operators like "!=" or ">="
or the like. We do at least a halfway-decent job of handling ver-
sions that aren’t strictly numeric, like "0.27_02", but exotic
stuff will likely cause problems.
In the future, the guts of this method might be replaced with a
call out to "version.pm".
config($key)
config($key, $value)
config() [deprecated]
[version 0.22]
With a single argument $key, returns the value associated with
that key in the "Config.pm" hash, including any changes the author
or user has specified.
With $key and $value arguments, sets the value for future callers
of "config($key)".
With no arguments, returns a hash reference containing all such
key-value pairs. This usage is deprecated, though, because it’s a
resource hog and violates encapsulation.
config_data($name)
config_data($name => $value)
[version 0.26]
With a single argument, returns the value of the configuration
variable $name. With two arguments, sets the given configuration
variable to the given value. The value may be any Perl scalar
that’s serializable with "Data::Dumper". For instance, if you
write a module that can use a MySQL or PostgreSQL back-end, you
might create configuration variables called "mysql_connect" and
"postgres_connect", and set each to an array of connection parame-
ters for "DBI->connect()".
Configuration values set in this way using the Module::Build
object will be available for querying during the build/test pro-
cess and after installation via the generated "...::ConfigData"
module, as "...::ConfigData->config($name)".
The feature() and "config_data()" methods represent Mod-
ule::Build’s main support for configuration of installed modules.
See also "SAVING CONFIGURATION INFORMATION" in Mod-
ule::Build::Authoring.
conflicts()
[version 0.21]
Returns a hash reference indicating the "conflicts" prerequisites
that were passed to the "new()" method.
contains_pod($file)
[version 0.20]
[Deprecated] Please see Module::Build::ModuleInfo instead.
Returns true if the given file appears to contain POD documenta-
tion. Currently this checks whether the file has a line beginning
with ’=pod’, ’=head’, or ’=item’, but the exact semantics may
change in the future.
copy_if_modified(%parameters)
[version 0.19]
Takes the file in the "from" parameter and copies it to the file
in the "to" parameter, or the directory in the "to_dir" parameter,
if the file has changed since it was last copied (or if it doesn’t
exist in the new location). By default the entire directory
structure of "from" will be copied into "to_dir"; an optional
"flatten" parameter will copy into "to_dir" without doing so.
Returns the path to the destination file, or "undef" if nothing
needed to be copied.
Any directories that need to be created in order to perform the
copying will be automatically created.
The destination file is set to read-only. If the source file has
the executable bit set, then the destination file will be made
executable.
create_build_script()
[version 0.05]
Creates an executable script called "Build" in the current direc-
tory that will be used to execute further user actions. This
script is roughly analogous (in function, not in form) to the
Makefile created by "ExtUtils::MakeMaker". This method also cre-
ates some temporary data in a directory called "_build/". Both of
these will be removed when the "realclean" action is performed.
Among the files created in "_build/" is a _build/prereqs file con-
taining the set of prerequisites for this distribution, as a hash
of hashes. This file may be "eval()"-ed to obtain the authorita-
tive set of prereqs, which might be different from the contents of
META.yml (because Build.PL might have set them dynamically). But
fancy developers take heed: do not put any fancy custom runtime
code in the _build/prereqs file, leave it as a static declaration
containing only strings and numbers. Similarly, do not alter the
structure of the internal "$self->{properties}{requires}" (etc.)
data members, because that’s where this data comes from.
current_action()
[version 0.28]
Returns the name of the currently-running action, such as "build"
or "test". This action is not necessarily the action that was
originally invoked by the user. For example, if the user invoked
the "test" action, current_action() would initially return "test".
However, action "test" depends on action "code", so cur-
rent_action() will return "code" while that dependency is being
executed. Once that action has completed, current_action() will
again return "test".
If you need to know the name of the original action invoked by the
user, see "invoked_action()" below.
depends_on(@actions)
[version 0.28]
Invokes the named action or list of actions in sequence. Using
this method is preferred to calling the action explicitly because
it performs some internal record-keeping, and it ensures that the
same action is not invoked multiple times (note: in future ver-
sions of Module::Build it’s conceivable that this run-only-once
mechanism will be changed to something more intelligent).
Note that the name of this method is something of a misnomer; it
should really be called something like
"invoke_actions_unless_already_invoked()" or something, but for
better or worse (perhaps better!) we were still thinking in
"make"-like dependency terms when we created this method.
See also dispatch(). The main distinction between the two is that
"depends_on()" is meant to call an action from inside another
action, whereas "dispatch()" is meant to set the very top action
in motion.
dir_contains($first_dir, $second_dir)
[version 0.28]
Returns true if the first directory logically contains the second
directory. This is just a convenience function because
"File::Spec" doesn’t really provide an easy way to figure this out
(but "Path::Class" does...).
dispatch($action, %args)
[version 0.03]
Invokes the build action $action. Optionally, a list of options
and their values can be passed in. This is equivalent to invoking
an action at the command line, passing in a list of options.
Custom options that have not been registered must be passed in as
a hash reference in a key named "args":
$build->dispatch(’foo’, verbose => 1, args => { my_option => ’value’ });
This method is intended to be used to programmatically invoke
build actions, e.g. by applications controlling Mod-
ule::Build-based builds rather than by subclasses.
See also depends_on(). The main distinction between the two is
that "depends_on()" is meant to call an action from inside another
action, whereas "dispatch()" is meant to set the very top action
in motion.
dist_dir()
[version 0.28]
Returns the name of the directory that will be created during the
"dist" action. The name is derived from the "dist_name" and
"dist_version" properties.
dist_name()
[version 0.21]
Returns the name of the current distribution, as passed to the
"new()" method in a "dist_name" or modified "module_name" parame-
ter.
dist_version()
[version 0.21]
Returns the version of the current distribution, as determined by
the "new()" method from a "dist_version", "dist_version_from", or
"module_name" parameter.
do_system($cmd, @args)
[version 0.21]
This is a fairly simple wrapper around Perl’s "system()" built-in
command. Given a command and an array of optional arguments, this
method will print the command to "STDOUT", and then execute it
using Perl’s "system()". It returns true or false to indicate
success or failure (the opposite of how "system()" works, but more
intuitive).
Note that if you supply a single argument to "do_system()", it
will/may be processed by the systems’s shell, and any special
characters will do their special things. If you supply multiple
arguments, no shell will get involved and the command will be exe-
cuted directly.
feature($name)
feature($name => $value)
[version 0.26]
With a single argument, returns true if the given feature is set.
With two arguments, sets the given feature to the given boolean
value. In this context, a "feature" is any optional functionality
of an installed module. For instance, if you write a module that
could optionally support a MySQL or PostgreSQL backend, you might
create features called "mysql_support" and "postgres_support", and
set them to true/false depending on whether the user has the
proper databases installed and configured.
Features set in this way using the Module::Build object will be
available for querying during the build/test process and after
installation via the generated "...::ConfigData" module, as
"...::ConfigData->feature($name)".
The "feature()" and "config_data()" methods represent Mod-
ule::Build’s main support for configuration of installed modules.
See also "SAVING CONFIGURATION INFORMATION" in Mod-
ule::Build::Authoring.
fix_shebang_line(@files)
[version 0.??]
Modify any "shebang" line in the specified files to use the path
to the perl executable being used for the current build. Files
are modified in-place. The existing shebang line must have a com-
mand that contains ""perl""; arguments to the command do not
count. In particular, this means that the use of "#!/usr/bin/env
perl" will not be changed.
For an explanation of shebang lines, see
<http://en.wikipedia.org/wiki/Shebang_%28Unix%29>.
have_c_compiler()
[version 0.21]
Returns true if the current system seems to have a working C com-
piler. We currently determine this by attempting to compile a
simple C source file and reporting whether the attempt was suc-
cessful.
install_base_relpaths()
install_base_relpaths($type)
install_base_relpaths($type => $path)
[version 0.28]
Set or retrieve the relative paths that are appended to
"install_base" for any installable element. This is useful if you
want to set the relative install path for custom build elements.
With no argument, it returns a reference to a hash containing all
elements and their respective values. This hash should not be mod-
ified directly; use the multi-argument below form to change val-
ues.
The single argument form returns the value associated with the
element $type.
The multi-argument form allows you to set the paths for element
types. $value must be a relative path using unix-like paths. (A
series of directories seperated by slashes. Eg ’foo/bar’.) The
return value is a localized path based on $value.
Assigning the value "undef" to an element causes it to be removed.
install_destination($type)
[version 0.28]
Returns the directory in which items of type $type (e.g. "lib",
"arch", "bin", or anything else returned by the "install_types()"
method) will be installed during the "install" action. Any set-
tings for "install_path", "install_base", and "prefix" are taken
into account when determining the return value.
install_path()
install_path($type)
install_path($type => $path)
[version 0.28]
Set or retrieve paths for specific installable elements. This is
useful when you want to examine any explicit install paths speci-
fied by the user on the command line, or if you want to set the
install path for a specific installable element based on another
attribute like "install_base()".
With no argument, it returns a reference to a hash containing all
elements and their respective values. This hash should not be mod-
ified directly; use the multi-argument below form to change val-
ues.
The single argument form returns the value associated with the
element $type.
The multi-argument form allows you to set the paths for element
types. The supplied $path should be an absolute path to install
elements of $type. The return value is $path.
Assigning the value "undef" to an element causes it to be removed.
install_types()
[version 0.28]
Returns a list of installable types that this build knows about.
These types each correspond to the name of a directory in blib/,
and the list usually includes items such as "lib", "arch", "bin",
"script", "libdoc", "bindoc", and if HTML documentation is to be
built, "libhtml" and "binhtml". Other user-defined types may also
exist.
invoked_action()
[version 0.28]
This is the name of the original action invoked by the user. This
value is set when the user invokes Build.PL, the Build script, or
programatically through the dispatch() method. It does not change
as sub-actions are executed as dependencies are evaluated.
To get the name of the currently executing dependency, see "cur-
rent_action()" above.
notes()
notes($key)
notes($key => $value)
[version 0.20]
The "notes()" value allows you to store your own persistent infor-
mation about the build, and to share that information among dif-
ferent entities involved in the build. See the example in the
"current()" method.
The "notes()" method is essentally a glorified hash access. With
no arguments, "notes()" returns the entire hash of notes. With
one argument, "notes($key)" returns the value associated with the
given key. With two arguments, "notes($key, $value)" sets the
value associated with the given key to $value and returns the new
value.
The lifetime of the "notes" data is for "a build" - that is, the
"notes" hash is created when "perl Build.PL" is run (or when the
"new()" method is run, if the Module::Build Perl API is being used
instead of called from a shell), and lasts until "perl Build.PL"
is run again or the "clean" action is run.
orig_dir()
[version 0.28]
Returns a string containing the working directory that was in
effect before the Build script chdir()-ed into the "base_dir".
This might be useful for writing wrapper tools that might need to
chdir() back out.
os_type()
[version 0.04]
If you’re subclassing Module::Build and some code needs to alter
its behavior based on the current platform, you may only need to
know whether you’re running on Windows, Unix, MacOS, VMS, etc.,
and not the fine-grained value of Perl’s $^O variable. The
"os_type()" method will return a string like "Windows", "Unix",
"MacOS", "VMS", or whatever is appropriate. If you’re running on
an unknown platform, it will return "undef" - there shouldn’t be
many unknown platforms though.
is_vmsish()
is_windowsish()
is_unixish()
Convenience functions that return a boolean value indicating
whether this platform behaves respectively like VMS, Windows, or
Unix. For arbitrary reasons other platforms don’t get their own
such functions, at least not yet.
prefix_relpaths()
prefix_relpaths($installdirs)
prefix_relpaths($installdirs, $type)
prefix_relpaths($installdirs, $type => $path)
[version 0.28]
Set or retrieve the relative paths that are appended to "prefix"
for any installable element. This is useful if you want to set
the relative install path for custom build elements.
With no argument, it returns a reference to a hash containing all
elements and their respective values as defined by the current
"installdirs" setting.
With a single argument, it returns a reference to a hash contain-
ing all elements and their respective values as defined by
$installdirs.
The hash returned by the above calls should not be modified
directly; use the three-argument below form to change values.
The two argument form returns the value associated with the ele-
ment $type.
The multi-argument form allows you to set the paths for element
types. $value must be a relative path using unix-like paths. (A
series of directories seperated by slashes. Eg ’foo/bar’.) The
return value is a localized path based on $value.
Assigning the value "undef" to an element causes it to be removed.
prepare_metadata()
[version 0.28]
This method is provided for authors to override to customize the
fields of META.yml. It is passed a YAML::Node node object which
can be modified as desired and then returned. E.g.
package My::Builder;
use base ’Module::Build’;
sub prepare_metadata {
my $self = shift;
my $node = $self->SUPER::prepare_metadata( shift );
$node->{custom_field} = ’foo’;
return $node;
}
prereq_failures()
[version 0.11]
Returns a data structure containing information about any failed
prerequisites (of any of the types described above), or "undef" if
all prerequisites are met.
The data structure returned is a hash reference. The top level
keys are the type of prerequisite failed, one of "requires",
"build_requires", "conflicts", or "recommends". The associated
values are hash references whose keys are the names of required
(or conflicting) modules. The associated values of those are hash
references indicating some information about the failure. For
example:
{
have => ’0.42’,
need => ’0.59’,
message => ’Version 0.42 is installed, but we need version 0.59’,
}
or
{
have => ’<none>’,
need => ’0.59’,
message => ’Prerequisite Foo isn’t installed’,
}
This hash has the same structure as the hash returned by the
"check_installed_status()" method, except that in the case of
"conflicts" dependencies we change the "need" key to "conflicts"
and construct a proper message.
Examples:
# Check a required dependency on Foo::Bar
if ( $build->prereq_failures->{requires}{Foo::Bar} ) { ...
# Check whether there were any failures
if ( $build->prereq_failures ) { ...
# Show messages for all failures
my $failures = $build->prereq_failures;
while (my ($type, $list) = each %$failures) {
while (my ($name, $hash) = each %$list) {
print "Failure for $name: $hash->{message}\n";
}
}
prereq_data()
[version 0.32]
Returns a reference to a hash describing all prerequisites. The
keys of the hash will the various prerequisite types (’requires’,
’build_requires’, ’configure_requires’, ’recommends’, or ’con-
flicts’) and the values will references to hashes of module names
and version numbers. Only prerequisites types that are defined
will be included. The "prereq_data" action is just a thin wrapper
around the "prereq_data()" method and dumps the hash as a string
that can be loaded using "eval()".
prereq_report()
[version 0.28]
Returns a human-readable (table-form) string showing all prerequi-
sites, the versions required, and the versions actually installed.
This can be useful for reviewing the configuration of your system
prior to a build, or when compiling data to send for a bug report.
The "prereq_report" action is just a thin wrapper around the "pre-
req_report()" method.
prompt($message, $default)
[version 0.12]
Asks the user a question and returns their response as a string.
The first argument specifies the message to display to the user
(for example, "Where do you keep your money?"). The second argu-
ment, which is optional, specifies a default answer (for example,
"wallet"). The user will be asked the question once.
If "prompt()" detects that it is not running interactively and
there is nothing on STDIN or if the PERL_MM_USE_DEFAULT environ-
ment variable is set to true, the $default will be used without
prompting.
To prevent automated processes from blocking, the user must either
set PERL_MM_USE_DEFAULT or attach something to STDIN (this can be
a pipe/file containing a scripted set of answers or /dev/null.)
If no $default is provided an empty string will be used instead.
In non-interactive mode, the absence of $default is an error
(though explicitly passing "undef()" as the default is valid as of
0.27.)
This method may be called as a class or object method.
recommends()
[version 0.21]
Returns a hash reference indicating the "recommends" prerequisites
that were passed to the "new()" method.
requires()
[version 0.21]
Returns a hash reference indicating the "requires" prerequisites
that were passed to the "new()" method.
rscan_dir($dir, $pattern)
[version 0.28]
Uses "File::Find" to traverse the directory $dir, returning a ref-
erence to an array of entries matching $pattern. $pattern may
either be a regular expression (using "qr//" or just a plain
string), or a reference to a subroutine that will return true for
wanted entries. If $pattern is not given, all entries will be
returned.
Examples:
# All the *.pm files in lib/
$m->rscan_dir(’lib’, qr/\.pm$/)
# All the files in blib/ that aren’t *.html files
$m->rscan_dir(’blib’, sub {-f $_ and not /\.html$/});
# All the files in t/
$m->rscan_dir(’t’);
runtime_params()
runtime_params($key)
[version 0.28]
The "runtime_params()" method stores the values passed on the com-
mand line for valid properties (that is, any command line options
for which "valid_property()" returns a true value). The value on
the command line may override the default value for a property, as
well as any value specified in a call to "new()". This allows you
to programmatically tell if "perl Build.PL" or any execution of
"./Build" had command line options specified that override valid
properties.
The "runtime_params()" method is essentally a glorified read-only
hash. With no arguments, "runtime_params()" returns the entire
hash of properties specified on the command line. With one argu-
ment, "runtime_params($key)" returns the value associated with the
given key.
The lifetime of the "runtime_params" data is for "a build" - that
is, the "runtime_params" hash is created when "perl Build.PL" is
run (or when the "new()" method is called, if the Module::Build
Perl API is being used instead of called from a shell), and lasts
until "perl Build.PL" is run again or the "clean" action is run.
script_files()
[version 0.18]
Returns a hash reference whose keys are the perl script files to
be installed, if any. This corresponds to the "script_files"
parameter to the "new()" method. With an optional argument, this
parameter may be set dynamically.
For backward compatibility, the "scripts()" method does exactly
the same thing as "script_files()". "scripts()" is deprecated,
but it will stay around for several versions to give people time
to transition.
up_to_date($source_file, $derived_file)
up_to_date(\@source_files, \@derived_files)
[version 0.20]
This method can be used to compare a set of source files to a set
of derived files. If any of the source files are newer than any
of the derived files, it returns false. Additionally, if any of
the derived files do not exist, it returns false. Otherwise it
returns true.
The arguments may be either a scalar or an array reference of file
names.
y_n($message, $default)
[version 0.12]
Asks the user a yes/no question using "prompt()" and returns true
or false accordingly. The user will be asked the question repeat-
edly until they give an answer that looks like "yes" or "no".
The first argument specifies the message to display to the user
(for example, "Shall I invest your money for you?"), and the sec-
ond argument specifies the default answer (for example, "y").
Note that the default is specified as a string like "y" or "n",
and the return value is a Perl boolean value like 1 or 0. I
thought about this for a while and this seemed like the most use-
ful way to do it.
This method may be called as a class or object method.
Autogenerated Accessors
In addition to the aforementioned methods, there are also some get/set
accessor methods for the following properties:
PL_files()
allow_mb_mismatch()
autosplit()
base_dir()
bindoc_dirs()
blib()
build_bat()
build_class()
build_elements()
build_requires()
build_script()
c_source()
config_dir()
configure_requires()
conflicts()
create_license()
create_makefile_pl()
create_packlist()
create_readme()
debugger()
destdir()
get_options()
html_css()
include_dirs()
install_base()
install_sets()
installdirs()
libdoc_dirs()
license()
magic_number()
mb_version()
meta_add()
meta_merge()
metafile()
module_name()
orig_dir()
original_prefix()
perl()
pm_files()
pod_files()
pollute()
prefix()
prereq_action_types()
program_name()
quiet()
recommends()
recurse_into()
recursive_test_files()
requires()
scripts()
sign()
tap_harness_args()
test_file_exts()
use_rcfile()
use_tap_harness()
verbose()
xs_files()
MODULE METADATA
If you would like to add other useful metadata, "Module::Build" sup-
ports this with the "meta_add" and "meta_merge" arguments to "new".
The authoritative list of supported metadata can be found at
<http://module-build.sourceforge.net/META-spec-current.html>, but for
convenience - here are a few of the more useful ones:
keywords
For describing the distribution using keyword (or "tags") in order
to make CPAN.org indexing and search more efficient and useful.
See <http://module-build.sourceforge.net/META-spec-cur-
rent.html#keywords>.
resources
A list of additional resources available for users of the distri-
bution. This can include links to a homepage on the web, a bug-
tracker, the repository location, a even subscription page for the
distribution mailing list.
See <http://module-build.sourceforge.net/META-spec-cur-
rent.html#resources>.
AUTHOR
Ken Williams <kwilliams@cpan.org>
COPYRIGHT
Copyright (c) 2001-2006 Ken Williams. All rights reserved.
This library is free software; you can redistribute it and/or modify
it under the same terms as Perl itself.
SEE ALSO
perl(1), Module::Build(3), Module::Build::Authoring(3), Mod-
ule::Build::Cookbook(3), ExtUtils::MakeMaker(3), YAML(3)
META.yml Specification: <http://module-build.source-
forge.net/META-spec-current.html>
perl v5.8.8 2009-05-27 Module::Build::API(3)
