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1 | package ExtUtils::Liblist; |
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2 | |
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3 | use File::Spec; |
4 | require ExtUtils::Liblist::Kid; |
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5 | @ISA = qw(ExtUtils::Liblist::Kid File::Spec); |
6 | |
7 | sub lsdir { |
8 | shift; |
9 | my $rex = qr/$_[1]/; |
10 | opendir my $dir, $_[0]; |
11 | grep /$rex/, readdir $dir; |
12 | } |
13 | |
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14 | __END__ |
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15 | |
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16 | =head1 NAME |
17 | |
18 | ExtUtils::Liblist - determine libraries to use and how to use them |
19 | |
20 | =head1 SYNOPSIS |
21 | |
22 | C<require ExtUtils::Liblist;> |
23 | |
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24 | C<ExtUtils::Liblist::ext($self, $potential_libs, $verbose, $need_names);> |
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25 | |
26 | =head1 DESCRIPTION |
27 | |
28 | This utility takes a list of libraries in the form C<-llib1 -llib2 |
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29 | -llib3> and returns lines suitable for inclusion in an extension |
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30 | Makefile. Extra library paths may be included with the form |
31 | C<-L/another/path> this will affect the searches for all subsequent |
32 | libraries. |
33 | |
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34 | It returns an array of four or five scalar values: EXTRALIBS, |
35 | BSLOADLIBS, LDLOADLIBS, LD_RUN_PATH, and, optionally, a reference to |
36 | the array of the filenames of actual libraries. Some of these don't |
37 | mean anything unless on Unix. See the details about those platform |
38 | specifics below. The list of the filenames is returned only if |
39 | $need_names argument is true. |
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40 | |
41 | Dependent libraries can be linked in one of three ways: |
42 | |
43 | =over 2 |
44 | |
45 | =item * For static extensions |
46 | |
47 | by the ld command when the perl binary is linked with the extension |
48 | library. See EXTRALIBS below. |
49 | |
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50 | =item * For dynamic extensions at build/link time |
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51 | |
52 | by the ld command when the shared object is built/linked. See |
53 | LDLOADLIBS below. |
54 | |
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55 | =item * For dynamic extensions at load time |
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56 | |
57 | by the DynaLoader when the shared object is loaded. See BSLOADLIBS |
58 | below. |
59 | |
60 | =back |
61 | |
62 | =head2 EXTRALIBS |
63 | |
64 | List of libraries that need to be linked with when linking a perl |
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65 | binary which includes this extension. Only those libraries that |
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66 | actually exist are included. These are written to a file and used |
67 | when linking perl. |
68 | |
69 | =head2 LDLOADLIBS and LD_RUN_PATH |
70 | |
71 | List of those libraries which can or must be linked into the shared |
72 | library when created using ld. These may be static or dynamic |
73 | libraries. LD_RUN_PATH is a colon separated list of the directories |
74 | in LDLOADLIBS. It is passed as an environment variable to the process |
75 | that links the shared library. |
76 | |
77 | =head2 BSLOADLIBS |
78 | |
79 | List of those libraries that are needed but can be linked in |
80 | dynamically at run time on this platform. SunOS/Solaris does not need |
81 | this because ld records the information (from LDLOADLIBS) into the |
82 | object file. This list is used to create a .bs (bootstrap) file. |
83 | |
84 | =head1 PORTABILITY |
85 | |
86 | This module deals with a lot of system dependencies and has quite a |
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87 | few architecture specific C<if>s in the code. |
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88 | |
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89 | =head2 VMS implementation |
90 | |
91 | The version of ext() which is executed under VMS differs from the |
92 | Unix-OS/2 version in several respects: |
93 | |
94 | =over 2 |
95 | |
96 | =item * |
97 | |
98 | Input library and path specifications are accepted with or without the |
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99 | C<-l> and C<-L> prefixes used by Unix linkers. If neither prefix is |
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100 | present, a token is considered a directory to search if it is in fact |
101 | a directory, and a library to search for otherwise. Authors who wish |
102 | their extensions to be portable to Unix or OS/2 should use the Unix |
103 | prefixes, since the Unix-OS/2 version of ext() requires them. |
104 | |
105 | =item * |
106 | |
107 | Wherever possible, shareable images are preferred to object libraries, |
108 | and object libraries to plain object files. In accordance with VMS |
109 | naming conventions, ext() looks for files named I<lib>shr and I<lib>rtl; |
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110 | it also looks for I<lib>lib and libI<lib> to accommodate Unix conventions |
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111 | used in some ported software. |
112 | |
113 | =item * |
114 | |
115 | For each library that is found, an appropriate directive for a linker options |
116 | file is generated. The return values are space-separated strings of |
117 | these directives, rather than elements used on the linker command line. |
118 | |
119 | =item * |
120 | |
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121 | LDLOADLIBS contains both the libraries found based on C<$potential_libs> and |
122 | the CRTLs, if any, specified in Config.pm. EXTRALIBS contains just those |
123 | libraries found based on C<$potential_libs>. BSLOADLIBS and LD_RUN_PATH |
124 | are always empty. |
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125 | |
126 | =back |
127 | |
128 | In addition, an attempt is made to recognize several common Unix library |
129 | names, and filter them out or convert them to their VMS equivalents, as |
130 | appropriate. |
131 | |
132 | In general, the VMS version of ext() should properly handle input from |
133 | extensions originally designed for a Unix or VMS environment. If you |
134 | encounter problems, or discover cases where the search could be improved, |
135 | please let us know. |
136 | |
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137 | =head2 Win32 implementation |
138 | |
139 | The version of ext() which is executed under Win32 differs from the |
140 | Unix-OS/2 version in several respects: |
141 | |
142 | =over 2 |
143 | |
144 | =item * |
145 | |
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146 | If C<$potential_libs> is empty, the return value will be empty. |
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147 | Otherwise, the libraries specified by C<$Config{perllibs}> (see Config.pm) |
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148 | will be appended to the list of C<$potential_libs>. The libraries |
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149 | will be searched for in the directories specified in C<$potential_libs>, |
150 | C<$Config{libpth}>, and in C<$Config{installarchlib}/CORE>. |
151 | For each library that is found, a space-separated list of fully qualified |
152 | library pathnames is generated. |
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153 | |
154 | =item * |
155 | |
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156 | Input library and path specifications are accepted with or without the |
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157 | C<-l> and C<-L> prefixes used by Unix linkers. |
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158 | |
159 | An entry of the form C<-La:\foo> specifies the C<a:\foo> directory to look |
160 | for the libraries that follow. |
161 | |
162 | An entry of the form C<-lfoo> specifies the library C<foo>, which may be |
163 | spelled differently depending on what kind of compiler you are using. If |
164 | you are using GCC, it gets translated to C<libfoo.a>, but for other win32 |
165 | compilers, it becomes C<foo.lib>. If no files are found by those translated |
166 | names, one more attempt is made to find them using either C<foo.a> or |
167 | C<libfoo.lib>, depending on whether GCC or some other win32 compiler is |
168 | being used, respectively. |
169 | |
170 | If neither the C<-L> or C<-l> prefix is present in an entry, the entry is |
171 | considered a directory to search if it is in fact a directory, and a |
172 | library to search for otherwise. The C<$Config{lib_ext}> suffix will |
173 | be appended to any entries that are not directories and don't already have |
174 | the suffix. |
175 | |
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176 | Note that the C<-L> and C<-l> prefixes are B<not required>, but authors |
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177 | who wish their extensions to be portable to Unix or OS/2 should use the |
178 | prefixes, since the Unix-OS/2 version of ext() requires them. |
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179 | |
180 | =item * |
181 | |
182 | Entries cannot be plain object files, as many Win32 compilers will |
183 | not handle object files in the place of libraries. |
184 | |
185 | =item * |
186 | |
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187 | Entries in C<$potential_libs> beginning with a colon and followed by |
188 | alphanumeric characters are treated as flags. Unknown flags will be ignored. |
189 | |
190 | An entry that matches C</:nodefault/i> disables the appending of default |
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191 | libraries found in C<$Config{perllibs}> (this should be only needed very rarely). |
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192 | |
193 | An entry that matches C</:nosearch/i> disables all searching for |
194 | the libraries specified after it. Translation of C<-Lfoo> and |
195 | C<-lfoo> still happens as appropriate (depending on compiler being used, |
196 | as reflected by C<$Config{cc}>), but the entries are not verified to be |
197 | valid files or directories. |
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198 | |
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199 | An entry that matches C</:search/i> reenables searching for |
200 | the libraries specified after it. You can put it at the end to |
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201 | enable searching for default libraries specified by C<$Config{perllibs}>. |
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202 | |
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203 | =item * |
204 | |
205 | The libraries specified may be a mixture of static libraries and |
206 | import libraries (to link with DLLs). Since both kinds are used |
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207 | pretty transparently on the Win32 platform, we do not attempt to |
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208 | distinguish between them. |
209 | |
210 | =item * |
211 | |
212 | LDLOADLIBS and EXTRALIBS are always identical under Win32, and BSLOADLIBS |
213 | and LD_RUN_PATH are always empty (this may change in future). |
214 | |
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215 | =item * |
216 | |
217 | You must make sure that any paths and path components are properly |
218 | surrounded with double-quotes if they contain spaces. For example, |
219 | C<$potential_libs> could be (literally): |
220 | |
221 | "-Lc:\Program Files\vc\lib" msvcrt.lib "la test\foo bar.lib" |
222 | |
223 | Note how the first and last entries are protected by quotes in order |
224 | to protect the spaces. |
225 | |
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226 | =item * |
227 | |
228 | Since this module is most often used only indirectly from extension |
229 | C<Makefile.PL> files, here is an example C<Makefile.PL> entry to add |
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230 | a library to the build process for an extension: |
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231 | |
232 | LIBS => ['-lgl'] |
233 | |
234 | When using GCC, that entry specifies that MakeMaker should first look |
235 | for C<libgl.a> (followed by C<gl.a>) in all the locations specified by |
236 | C<$Config{libpth}>. |
237 | |
238 | When using a compiler other than GCC, the above entry will search for |
239 | C<gl.lib> (followed by C<libgl.lib>). |
240 | |
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241 | If the library happens to be in a location not in C<$Config{libpth}>, |
242 | you need: |
243 | |
244 | LIBS => ['-Lc:\gllibs -lgl'] |
245 | |
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246 | Here is a less often used example: |
247 | |
248 | LIBS => ['-lgl', ':nosearch -Ld:\mesalibs -lmesa -luser32'] |
249 | |
250 | This specifies a search for library C<gl> as before. If that search |
251 | fails to find the library, it looks at the next item in the list. The |
252 | C<:nosearch> flag will prevent searching for the libraries that follow, |
253 | so it simply returns the value as C<-Ld:\mesalibs -lmesa -luser32>, |
254 | since GCC can use that value as is with its linker. |
255 | |
256 | When using the Visual C compiler, the second item is returned as |
257 | C<-libpath:d:\mesalibs mesa.lib user32.lib>. |
258 | |
259 | When using the Borland compiler, the second item is returned as |
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260 | C<-Ld:\mesalibs mesa.lib user32.lib>, and MakeMaker takes care of |
261 | moving the C<-Ld:\mesalibs> to the correct place in the linker |
262 | command line. |
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263 | |
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264 | =back |
265 | |
266 | |
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267 | =head1 SEE ALSO |
268 | |
269 | L<ExtUtils::MakeMaker> |
270 | |
271 | =cut |
272 | |