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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

# User Rev Content
1 root 1.1 =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 root 1.2 our $VERSION = 0.03;
70 root 1.1
71 root 1.2 use Exporter 'import';
72 root 1.1
73     our @EXPORT = qw(extutils_cxx);
74    
75 root 1.2 use ExtUtils::MakeMaker::Config ();
76    
77 root 1.1 =item extutils_cxx BLOCK;
78    
79     This function temporarily does hideous things so you can call
80     C<WriteMakefile> or similar functions in the BLOCK normally. See the
81     description, above, for more details.
82    
83     =cut
84    
85     use Config;
86    
87     our %cc = (
88     gcc => "g++",
89     clang => "clang++",
90     xlc => "xlC",
91     cc => "g++",
92     c89 => "g++",
93     );
94    
95     sub _ccrepl {
96     my ($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 root 1.2 local $ExtUtils::MakeMaker::Config::Config{cc} = $tie->{cc};
135     local $ExtUtils::MakeMaker::Config::Config{ld} = $tie->{ld};
136    
137 root 1.1 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