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1 | package ExtUtils::Liblist; |
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2 | |
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3 | use strict; |
4 | |
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5 | our $VERSION = '6.49_01'; |
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6 | |
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7 | use File::Spec; |
8 | require ExtUtils::Liblist::Kid; |
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9 | our @ISA = qw(ExtUtils::Liblist::Kid File::Spec); |
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10 | |
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11 | # Backwards compatibility with old interface. |
12 | sub ext { |
13 | goto &ExtUtils::Liblist::Kid::ext; |
14 | } |
15 | |
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16 | sub lsdir { |
17 | shift; |
18 | my $rex = qr/$_[1]/; |
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19 | opendir DIR, $_[0]; |
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20 | my @out = grep /$rex/, readdir DIR; |
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21 | closedir DIR; |
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22 | return @out; |
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23 | } |
24 | |
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25 | __END__ |
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26 | |
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27 | =head1 NAME |
28 | |
29 | ExtUtils::Liblist - determine libraries to use and how to use them |
30 | |
31 | =head1 SYNOPSIS |
32 | |
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33 | require ExtUtils::Liblist; |
34 | |
35 | $MM->ext($potential_libs, $verbose, $need_names); |
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36 | |
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37 | # Usually you can get away with: |
38 | ExtUtils::Liblist->ext($potential_libs, $verbose, $need_names) |
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39 | |
40 | =head1 DESCRIPTION |
41 | |
42 | This utility takes a list of libraries in the form C<-llib1 -llib2 |
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43 | -llib3> and returns lines suitable for inclusion in an extension |
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44 | Makefile. Extra library paths may be included with the form |
45 | C<-L/another/path> this will affect the searches for all subsequent |
46 | libraries. |
47 | |
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48 | It returns an array of four or five scalar values: EXTRALIBS, |
49 | BSLOADLIBS, LDLOADLIBS, LD_RUN_PATH, and, optionally, a reference to |
50 | the array of the filenames of actual libraries. Some of these don't |
51 | mean anything unless on Unix. See the details about those platform |
52 | specifics below. The list of the filenames is returned only if |
53 | $need_names argument is true. |
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54 | |
55 | Dependent libraries can be linked in one of three ways: |
56 | |
57 | =over 2 |
58 | |
59 | =item * For static extensions |
60 | |
61 | by the ld command when the perl binary is linked with the extension |
62 | library. See EXTRALIBS below. |
63 | |
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64 | =item * For dynamic extensions at build/link time |
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65 | |
66 | by the ld command when the shared object is built/linked. See |
67 | LDLOADLIBS below. |
68 | |
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69 | =item * For dynamic extensions at load time |
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70 | |
71 | by the DynaLoader when the shared object is loaded. See BSLOADLIBS |
72 | below. |
73 | |
74 | =back |
75 | |
76 | =head2 EXTRALIBS |
77 | |
78 | List of libraries that need to be linked with when linking a perl |
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79 | binary which includes this extension. Only those libraries that |
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80 | actually exist are included. These are written to a file and used |
81 | when linking perl. |
82 | |
83 | =head2 LDLOADLIBS and LD_RUN_PATH |
84 | |
85 | List of those libraries which can or must be linked into the shared |
86 | library when created using ld. These may be static or dynamic |
87 | libraries. LD_RUN_PATH is a colon separated list of the directories |
88 | in LDLOADLIBS. It is passed as an environment variable to the process |
89 | that links the shared library. |
90 | |
91 | =head2 BSLOADLIBS |
92 | |
93 | List of those libraries that are needed but can be linked in |
94 | dynamically at run time on this platform. SunOS/Solaris does not need |
95 | this because ld records the information (from LDLOADLIBS) into the |
96 | object file. This list is used to create a .bs (bootstrap) file. |
97 | |
98 | =head1 PORTABILITY |
99 | |
100 | This module deals with a lot of system dependencies and has quite a |
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101 | few architecture specific C<if>s in the code. |
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102 | |
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103 | =head2 VMS implementation |
104 | |
105 | The version of ext() which is executed under VMS differs from the |
106 | Unix-OS/2 version in several respects: |
107 | |
108 | =over 2 |
109 | |
110 | =item * |
111 | |
112 | Input library and path specifications are accepted with or without the |
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113 | C<-l> and C<-L> prefixes used by Unix linkers. If neither prefix is |
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114 | present, a token is considered a directory to search if it is in fact |
115 | a directory, and a library to search for otherwise. Authors who wish |
116 | their extensions to be portable to Unix or OS/2 should use the Unix |
117 | prefixes, since the Unix-OS/2 version of ext() requires them. |
118 | |
119 | =item * |
120 | |
121 | Wherever possible, shareable images are preferred to object libraries, |
122 | and object libraries to plain object files. In accordance with VMS |
123 | naming conventions, ext() looks for files named I<lib>shr and I<lib>rtl; |
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124 | it also looks for I<lib>lib and libI<lib> to accommodate Unix conventions |
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125 | used in some ported software. |
126 | |
127 | =item * |
128 | |
129 | For each library that is found, an appropriate directive for a linker options |
130 | file is generated. The return values are space-separated strings of |
131 | these directives, rather than elements used on the linker command line. |
132 | |
133 | =item * |
134 | |
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135 | LDLOADLIBS contains both the libraries found based on C<$potential_libs> and |
136 | the CRTLs, if any, specified in Config.pm. EXTRALIBS contains just those |
137 | libraries found based on C<$potential_libs>. BSLOADLIBS and LD_RUN_PATH |
138 | are always empty. |
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139 | |
140 | =back |
141 | |
142 | In addition, an attempt is made to recognize several common Unix library |
143 | names, and filter them out or convert them to their VMS equivalents, as |
144 | appropriate. |
145 | |
146 | In general, the VMS version of ext() should properly handle input from |
147 | extensions originally designed for a Unix or VMS environment. If you |
148 | encounter problems, or discover cases where the search could be improved, |
149 | please let us know. |
150 | |
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151 | =head2 Win32 implementation |
152 | |
153 | The version of ext() which is executed under Win32 differs from the |
154 | Unix-OS/2 version in several respects: |
155 | |
156 | =over 2 |
157 | |
158 | =item * |
159 | |
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160 | If C<$potential_libs> is empty, the return value will be empty. |
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161 | Otherwise, the libraries specified by C<$Config{perllibs}> (see Config.pm) |
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162 | will be appended to the list of C<$potential_libs>. The libraries |
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163 | will be searched for in the directories specified in C<$potential_libs>, |
164 | C<$Config{libpth}>, and in C<$Config{installarchlib}/CORE>. |
165 | For each library that is found, a space-separated list of fully qualified |
166 | library pathnames is generated. |
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167 | |
168 | =item * |
169 | |
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170 | Input library and path specifications are accepted with or without the |
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171 | C<-l> and C<-L> prefixes used by Unix linkers. |
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172 | |
173 | An entry of the form C<-La:\foo> specifies the C<a:\foo> directory to look |
174 | for the libraries that follow. |
175 | |
176 | An entry of the form C<-lfoo> specifies the library C<foo>, which may be |
177 | spelled differently depending on what kind of compiler you are using. If |
178 | you are using GCC, it gets translated to C<libfoo.a>, but for other win32 |
179 | compilers, it becomes C<foo.lib>. If no files are found by those translated |
180 | names, one more attempt is made to find them using either C<foo.a> or |
181 | C<libfoo.lib>, depending on whether GCC or some other win32 compiler is |
182 | being used, respectively. |
183 | |
184 | If neither the C<-L> or C<-l> prefix is present in an entry, the entry is |
185 | considered a directory to search if it is in fact a directory, and a |
186 | library to search for otherwise. The C<$Config{lib_ext}> suffix will |
187 | be appended to any entries that are not directories and don't already have |
188 | the suffix. |
189 | |
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190 | Note that the C<-L> and C<-l> prefixes are B<not required>, but authors |
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191 | who wish their extensions to be portable to Unix or OS/2 should use the |
192 | prefixes, since the Unix-OS/2 version of ext() requires them. |
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193 | |
194 | =item * |
195 | |
196 | Entries cannot be plain object files, as many Win32 compilers will |
197 | not handle object files in the place of libraries. |
198 | |
199 | =item * |
200 | |
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201 | Entries in C<$potential_libs> beginning with a colon and followed by |
202 | alphanumeric characters are treated as flags. Unknown flags will be ignored. |
203 | |
204 | An entry that matches C</:nodefault/i> disables the appending of default |
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205 | libraries found in C<$Config{perllibs}> (this should be only needed very rarely). |
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206 | |
207 | An entry that matches C</:nosearch/i> disables all searching for |
208 | the libraries specified after it. Translation of C<-Lfoo> and |
209 | C<-lfoo> still happens as appropriate (depending on compiler being used, |
210 | as reflected by C<$Config{cc}>), but the entries are not verified to be |
211 | valid files or directories. |
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212 | |
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213 | An entry that matches C</:search/i> reenables searching for |
214 | the libraries specified after it. You can put it at the end to |
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215 | enable searching for default libraries specified by C<$Config{perllibs}>. |
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216 | |
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217 | =item * |
218 | |
219 | The libraries specified may be a mixture of static libraries and |
220 | import libraries (to link with DLLs). Since both kinds are used |
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221 | pretty transparently on the Win32 platform, we do not attempt to |
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222 | distinguish between them. |
223 | |
224 | =item * |
225 | |
226 | LDLOADLIBS and EXTRALIBS are always identical under Win32, and BSLOADLIBS |
227 | and LD_RUN_PATH are always empty (this may change in future). |
228 | |
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229 | =item * |
230 | |
231 | You must make sure that any paths and path components are properly |
232 | surrounded with double-quotes if they contain spaces. For example, |
233 | C<$potential_libs> could be (literally): |
234 | |
235 | "-Lc:\Program Files\vc\lib" msvcrt.lib "la test\foo bar.lib" |
236 | |
237 | Note how the first and last entries are protected by quotes in order |
238 | to protect the spaces. |
239 | |
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240 | =item * |
241 | |
242 | Since this module is most often used only indirectly from extension |
243 | C<Makefile.PL> files, here is an example C<Makefile.PL> entry to add |
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244 | a library to the build process for an extension: |
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245 | |
246 | LIBS => ['-lgl'] |
247 | |
248 | When using GCC, that entry specifies that MakeMaker should first look |
249 | for C<libgl.a> (followed by C<gl.a>) in all the locations specified by |
250 | C<$Config{libpth}>. |
251 | |
252 | When using a compiler other than GCC, the above entry will search for |
253 | C<gl.lib> (followed by C<libgl.lib>). |
254 | |
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255 | If the library happens to be in a location not in C<$Config{libpth}>, |
256 | you need: |
257 | |
258 | LIBS => ['-Lc:\gllibs -lgl'] |
259 | |
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260 | Here is a less often used example: |
261 | |
262 | LIBS => ['-lgl', ':nosearch -Ld:\mesalibs -lmesa -luser32'] |
263 | |
264 | This specifies a search for library C<gl> as before. If that search |
265 | fails to find the library, it looks at the next item in the list. The |
266 | C<:nosearch> flag will prevent searching for the libraries that follow, |
267 | so it simply returns the value as C<-Ld:\mesalibs -lmesa -luser32>, |
268 | since GCC can use that value as is with its linker. |
269 | |
270 | When using the Visual C compiler, the second item is returned as |
271 | C<-libpath:d:\mesalibs mesa.lib user32.lib>. |
272 | |
273 | When using the Borland compiler, the second item is returned as |
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274 | C<-Ld:\mesalibs mesa.lib user32.lib>, and MakeMaker takes care of |
275 | moving the C<-Ld:\mesalibs> to the correct place in the linker |
276 | command line. |
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277 | |
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278 | =back |
279 | |
280 | |
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281 | =head1 SEE ALSO |
282 | |
283 | L<ExtUtils::MakeMaker> |
284 | |
285 | =cut |
286 | |