1 package ExtUtils::MakeMaker::FAQ;
3 (our $VERSION) = sprintf "%03d", q$Revision: 1.7 $ =~ /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$ =~ /(\d+)/g;
80 On your next check in, $Z<>Revision$ will magically be expanded to contain
81 the current revision #.
83 $VERSION = sprintf "%d.%03d", q$Revision: 1.7 $ =~ /(\d+)/g;
85 Every time the file is checked in the $Z<>Revision$ will be updated,
86 updating your $VERSION.
88 In CVS version 1.9 is followed by 1.10. Since CPAN compares version
89 numbers numerically we use a sprintf() to convert 1.9 to 1.009 and
90 1.10 to 1.010 which compare properly.
92 If branches are involved (ie. $Z<>Revision: 1.5.3.4) its a little more
95 # must be all on one line or MakeMaker will get confused.
96 $VERSION = do { my @r = (q$Revision$ =~ /\d+/g); sprintf "%d."."%03d" x $#r, @r };
98 =item What's this F<META.yml> thing and how did it get in my F<MANIFEST>?!
100 F<META.yml> is a module meta-data file pioneered by Module::Build and
101 automatically generated as part of the 'distdir' target (and thus
102 'dist'). See L<ExtUtils::MakeMaker/"Module Meta-Data">.
104 To shut off its generation, pass the C<NO_META> flag to C<WriteMakefile()>.
112 =item How to I prevent "object version X.XX does not match bootstrap parameter Y.YY" errors?
114 XS code is very sensitive to the module version number and will
115 complain if the version number in your Perl module doesn't match. If
116 you change your module's version # without reruning Makefile.PL the old
117 version number will remain in the Makefile causing the XS code to be built
118 with the wrong number.
120 To avoid this, you can force the Makefile to be rebuilt whenever you
121 change the module containing the version number by adding this to your
122 WriteMakefile() arguments.
124 depend => { '$(FIRST_MAKEFILE)' => '$(VERSION_FROM)' }
127 =item How do I make two or more XS files coexist in the same directory?
129 Sometimes you need to have two and more XS files in the same package.
130 One way to go is to put them into separate directories, but sometimes
131 this is not the most suitable solution. The following technique allows
132 you to put two (and more) XS files in the same directory.
134 Let's assume that we have a package C<Cool::Foo>, which includes
135 C<Cool::Foo> and C<Cool::Bar> modules each having a separate XS
136 file. First we use the following I<Makefile.PL>:
138 use ExtUtils::MakeMaker;
142 VERSION_FROM => 'Foo.pm',
143 OBJECT => q/$(O_FILES)/,
144 # ... other attrs ...
147 Notice the C<OBJECT> attribute. MakeMaker generates the following
148 variables in I<Makefile>:
150 # Handy lists of source code files:
158 Therefore we can use the C<O_FILES> variable to tell MakeMaker to use
159 these objects into the shared library.
161 That's pretty much it. Now write I<Foo.pm> and I<Foo.xs>, I<Bar.pm>
162 and I<Bar.xs>, where I<Foo.pm> bootstraps the shared library and
163 I<Bar.pm> simply loading I<Foo.pm>.
165 The only issue left is to how to bootstrap I<Bar.xs>. This is done
168 MODULE = Cool::Foo PACKAGE = Cool::Foo
171 # boot the second XS file
172 boot_Cool__Bar(aTHX_ cv);
174 If you have more than two files, this is the place where you should
175 boot extra XS files from.
177 The following four files sum up all the details discussed so far.
185 our @ISA = qw(DynaLoader);
186 our $VERSION = '0.01';
187 bootstrap Cool::Foo $VERSION;
195 use Cool::Foo; # bootstraps Bar.xs
205 MODULE = Cool::Foo PACKAGE = Cool::Foo
208 # boot the second XS file
209 boot_Cool__Bar(aTHX_ cv);
211 MODULE = Cool::Foo PACKAGE = Cool::Foo PREFIX = cool_foo_
214 cool_foo_perl_rules()
217 fprintf(stderr, "Cool::Foo says: Perl Rules\n");
225 MODULE = Cool::Bar PACKAGE = Cool::Bar PREFIX = cool_bar_
228 cool_bar_perl_rules()
231 fprintf(stderr, "Cool::Bar says: Perl Rules\n");
233 And of course a very basic test:
238 BEGIN { plan tests => 1 };
241 Cool::Foo::perl_rules();
242 Cool::Bar::perl_rules();
245 This tip has been brought to you by Nick Ing-Simmons and Stas Bekman.
251 If you have a question you'd like to see added to the FAQ (whether or
252 not you have the answer) please send it to makemaker@perl.org.
256 The denizens of makemaker@perl.org.
260 L<ExtUtils::MakeMaker>