1 package ExtUtils::MakeMaker::FAQ;
3 (our $VERSION) = sprintf "%03d", q$Revision: 1.9 $ =~ /Revision:\s+(\S+)/;
10 ExtUtils::MakeMaker::FAQ - Frequently Asked Questions About MakeMaker
14 FAQs, tricks and tips for C<ExtUtils::MakeMaker>.
16 =head2 Philosophy and History
20 =item Why not just use <insert other build config tool here>?
22 Why did MakeMaker reinvent the build configuration wheel? Why not
23 just use autoconf or automake or ppm or Ant or ...
25 There are many reasons, but the major one is cross-platform
28 Perl is one of the most ported pieces of software ever. It works on
29 operating systems I've never even heard of (see perlport for details).
30 It needs a build tool that can work on all those platforms and with
31 any wacky C compilers they might have.
33 No such build tool existed at the time and I only know of one now
37 =item What's Module::Build and how does it relate to MakeMaker?
39 Module::Build is a project by Ken Williams to supplant MakeMaker.
40 Its primary advantages are:
44 =item * pure perl. no make, no shell commands
46 =item * easier to customize
48 =item * cleaner internals
54 Module::Build is the official heir apparent to MakeMaker and we
55 encourage people to work on M::B rather than spending time improving
64 =item How do I keep my $VERSION up to date without resetting it manually?
66 Often you want to manually set the $VERSION in the main module
67 distribution because this is the version that everybody sees on CPAN
68 and maybe you want to customize it a bit. But for all the other
69 modules in your dist, $VERSION is really just bookkeeping and all that's
70 important is it goes up every time the module is changed. Doing this
71 by hand is a pain and you often forget.
73 Simplest way to do it automatically is to use your version control
74 system's revision number (you are using version control, right?).
76 In CVS and RCS you use $Z<>Revision$ writing it like so:
78 $VERSION = sprintf "%d.%03d", q$Revision: 1.9 $ =~ /(\d+)/g;
80 Every time the file is checked in the $Z<>Revision$ will be updated,
81 updating your $VERSION.
83 In CVS version 1.9 is followed by 1.10. Since CPAN compares version
84 numbers numerically we use a sprintf() to convert 1.9 to 1.009 and
85 1.10 to 1.010 which compare properly.
87 If branches are involved (ie. $Z<>Revision: 1.5.3.4) its a little more
90 # must be all on one line or MakeMaker will get confused.
91 $VERSION = do { my @r = (q$Revision: 1.9 $ =~ /\d+/g); sprintf "%d."."%03d" x $#r, @r };
93 =item What's this F<META.yml> thing and how did it get in my F<MANIFEST>?!
95 F<META.yml> is a module meta-data file pioneered by Module::Build and
96 automatically generated as part of the 'distdir' target (and thus
97 'dist'). See L<ExtUtils::MakeMaker/"Module Meta-Data">.
99 To shut off its generation, pass the C<NO_META> flag to C<WriteMakefile()>.
107 =item How to I prevent "object version X.XX does not match bootstrap parameter Y.YY" errors?
109 XS code is very sensitive to the module version number and will
110 complain if the version number in your Perl module doesn't match. If
111 you change your module's version # without reruning Makefile.PL the old
112 version number will remain in the Makefile causing the XS code to be built
113 with the wrong number.
115 To avoid this, you can force the Makefile to be rebuilt whenever you
116 change the module containing the version number by adding this to your
117 WriteMakefile() arguments.
119 depend => { '$(FIRST_MAKEFILE)' => '$(VERSION_FROM)' }
122 =item How do I make two or more XS files coexist in the same directory?
124 Sometimes you need to have two and more XS files in the same package.
125 One way to go is to put them into separate directories, but sometimes
126 this is not the most suitable solution. The following technique allows
127 you to put two (and more) XS files in the same directory.
129 Let's assume that we have a package C<Cool::Foo>, which includes
130 C<Cool::Foo> and C<Cool::Bar> modules each having a separate XS
131 file. First we use the following I<Makefile.PL>:
133 use ExtUtils::MakeMaker;
137 VERSION_FROM => 'Foo.pm',
138 OBJECT => q/$(O_FILES)/,
139 # ... other attrs ...
142 Notice the C<OBJECT> attribute. MakeMaker generates the following
143 variables in I<Makefile>:
145 # Handy lists of source code files:
153 Therefore we can use the C<O_FILES> variable to tell MakeMaker to use
154 these objects into the shared library.
156 That's pretty much it. Now write I<Foo.pm> and I<Foo.xs>, I<Bar.pm>
157 and I<Bar.xs>, where I<Foo.pm> bootstraps the shared library and
158 I<Bar.pm> simply loading I<Foo.pm>.
160 The only issue left is to how to bootstrap I<Bar.xs>. This is done
163 MODULE = Cool::Foo PACKAGE = Cool::Foo
166 # boot the second XS file
167 boot_Cool__Bar(aTHX_ cv);
169 If you have more than two files, this is the place where you should
170 boot extra XS files from.
172 The following four files sum up all the details discussed so far.
180 our @ISA = qw(DynaLoader);
181 our $VERSION = '0.01';
182 bootstrap Cool::Foo $VERSION;
190 use Cool::Foo; # bootstraps Bar.xs
200 MODULE = Cool::Foo PACKAGE = Cool::Foo
203 # boot the second XS file
204 boot_Cool__Bar(aTHX_ cv);
206 MODULE = Cool::Foo PACKAGE = Cool::Foo PREFIX = cool_foo_
209 cool_foo_perl_rules()
212 fprintf(stderr, "Cool::Foo says: Perl Rules\n");
220 MODULE = Cool::Bar PACKAGE = Cool::Bar PREFIX = cool_bar_
223 cool_bar_perl_rules()
226 fprintf(stderr, "Cool::Bar says: Perl Rules\n");
228 And of course a very basic test:
233 BEGIN { plan tests => 1 };
236 Cool::Foo::perl_rules();
237 Cool::Bar::perl_rules();
240 This tip has been brought to you by Nick Ing-Simmons and Stas Bekman.
246 If you have a question you'd like to see added to the FAQ (whether or
247 not you have the answer) please send it to makemaker@perl.org.
251 The denizens of makemaker@perl.org.
255 L<ExtUtils::MakeMaker>