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Revision: 1.2
Committed: Mon Aug 14 05:26:35 2017 UTC (7 years, 3 months ago) by root
Branch: MAIN
CVS Tags: rel-0_03
Changes since 1.1: +7 -3 lines
Log Message:
0.03

File Contents

# Content
1 =head1 NAME
2
3 ExtUtils::CXX - support C++ XS files
4
5 =head1 SYNOPSIS
6
7 use ExtUtils::CXX;
8 use ExtUtils::MakeMaker;
9
10 # wrap calls to WriteMakefile or MakeMaker that are supposed to use
11 # C++ XS files into extutils_cxx blocks:
12
13 extutils_cxx {
14 WriteMakefile (
15 ... put your normal args here
16 );
17 };
18
19 =head1 DESCRIPTION
20
21 This module enables XS extensions written in C++. It is meant to be useful
22 for the users and installers of c++ modules, rather than the authors, by
23 having a single central place where to patch things, rather than to have
24 to patch every single module that overrides CC manually. That is, in the
25 worst case, you need to patch this module for your environment before
26 being able to CPAN-install further C++ modules; commonly, only setting a
27 few ENV variables is enough; and in the best case, it just works out of
28 the box.
29
30 (Comments on what to do and suggestions on how to achieve these things
31 better are welcome).
32
33 At the moment, it works by changing the values in C<%Config::Config>
34 temporarily. It does the following things:
35
36 =over 4
37
38 =item 1. It tries to change C<$Config{cc}> and C<$Config{ld}> into a C++ compiler.
39
40 If the environment variable C<$CXX> is set, then it's value will be used
41 to replace both (except if C<$PERL_CXXLD> is set, then that will be used for
42 C<$Config{ld}>.
43
44 (There is also a C<$PERL_CXX> which takes precedence over C<$CXX>).
45
46 The important thing is that the chosen C++ compiler compiles files with
47 a F<.c> ending as C++ - a generic compiler wrapper such as F<gcc> that
48 detects the lafguage by the file extension will I<not> work.
49
50 In the absence of these variables, it will do the following
51 transformations on what it guesses will be the compiler name:
52
53 gcc => g++
54 clang => clang++
55 xlc => xlC
56 cc => g++
57 c89 => g++
58
59 =back
60
61 =over 4
62
63 =cut
64
65 package ExtUtils::CXX;
66
67 use common::sense;
68
69 our $VERSION = 0.03;
70
71 use Exporter 'import';
72
73 our @EXPORT = qw(extutils_cxx);
74
75 use ExtUtils::MakeMaker::Config ();
76
77 =item extutils_cxx BLOCK;
78
79 This function temporarily does hideous things so you can call
80 C<WriteMakefile> or similar functions in the BLOCK normally. See the
81 description, above, for more details.
82
83 =cut
84
85 use Config;
86
87 our %cc = (
88 gcc => "g++",
89 clang => "clang++",
90 xlc => "xlC",
91 cc => "g++",
92 c89 => "g++",
93 );
94
95 sub _ccrepl {
96 my ($cfgvar, $env) = @_;
97
98 my $tie = tied %Config;
99
100 my $env = $ENV{"PERL_$env"} || $ENV{$env};
101
102 my $val = $tie->{$cfgvar};
103
104 if ($env) {
105 $val =~ s/^\S+/$env/;
106 } else {
107 keys %cc;
108 while (my ($k, $v) = each %cc) {
109 $val =~ s/^ (\S*[\/\\])? $k (-|\s|\d|$) /$1$v$2/x
110 and goto done;
111 }
112
113 $val =~ s/^\S+/g++/;
114
115 done: ;
116 }
117
118 $tie->{$cfgvar} = $val;
119 }
120
121 sub extutils_cxx(&) {
122 my ($cb) = @_;
123
124 # make sure these exist
125 @Config{qw(cc ld)};
126
127 my $tie = tied %Config;
128
129 # now dive into internals of Config and temporarily patch those values
130
131 local $tie->{cc} = $Config{cc}; _ccrepl cc => "CXX";
132 local $tie->{ld} = $Config{ld}; _ccrepl ld => ($ENV{PERL_CXXLD} ? "CXXLD" : "CXX");
133
134 local $ExtUtils::MakeMaker::Config::Config{cc} = $tie->{cc};
135 local $ExtUtils::MakeMaker::Config::Config{ld} = $tie->{ld};
136
137 eval {
138 $cb->();
139 };
140 die if $@;
141 }
142
143 =back
144
145 =head2 WHAT YOU HAVE TO DO
146
147 This module only makes your F<.xs> files compile as C++. It does not
148 provide magic C++ support for objects and typemaps, and does not help with
149 portability or writing your F<.xs> file. All of these you have to do -
150 google is your friend.
151
152 =head2 LIMITATIONS
153
154 Combining C++ and C is an art form in itself, and there is simply no
155 portable way to make it work - the platform might have a C compiler, but
156 no C++ compiler. The C++ compiler might be binary incompatible to the C
157 compiler, or might not run for other reasons, and in the end, C++ is more
158 of a moving target than C.
159
160 =head2 SEE ALSO
161
162 There is a module called C<ExtUtils::XSpp> that says it gives you C++ in
163 XS, by changing XS in some ways. I don't know what exactly it's purpose
164 is, but it might be a useful addition for C++ Xs development for you,
165 so you might want to look at it. It doesn't have C<ExtUtils::MakeMaker>
166 support, and there is a companion module that only supports the obsolete
167 (and very broken) C<Module::Build>, sour YMMV.
168
169 =head1 AUTHOR/CONTACT
170
171 Marc Lehmann <schmorp@schmorp.de>
172 http://software.schmorp.de/pkg/extutils-cxx.html
173
174 =cut
175
176 1
177