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1 | package ExtUtils::Liblist; |
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2 | |
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3 | use vars qw($VERSION); |
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4 | $VERSION = '1.00'; |
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5 | |
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6 | use File::Spec; |
7 | require ExtUtils::Liblist::Kid; |
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8 | @ISA = qw(ExtUtils::Liblist::Kid File::Spec); |
9 | |
10 | sub lsdir { |
11 | shift; |
12 | my $rex = qr/$_[1]/; |
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13 | opendir DIR, $_[0]; |
14 | grep /$rex/, readdir DIR; |
15 | closedir DIR; |
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16 | } |
17 | |
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18 | __END__ |
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19 | |
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20 | =head1 NAME |
21 | |
22 | ExtUtils::Liblist - determine libraries to use and how to use them |
23 | |
24 | =head1 SYNOPSIS |
25 | |
26 | C<require ExtUtils::Liblist;> |
27 | |
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28 | C<ExtUtils::Liblist::ext($self, $potential_libs, $verbose, $need_names);> |
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29 | |
30 | =head1 DESCRIPTION |
31 | |
32 | This utility takes a list of libraries in the form C<-llib1 -llib2 |
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33 | -llib3> and returns lines suitable for inclusion in an extension |
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34 | Makefile. Extra library paths may be included with the form |
35 | C<-L/another/path> this will affect the searches for all subsequent |
36 | libraries. |
37 | |
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38 | It returns an array of four or five scalar values: EXTRALIBS, |
39 | BSLOADLIBS, LDLOADLIBS, LD_RUN_PATH, and, optionally, a reference to |
40 | the array of the filenames of actual libraries. Some of these don't |
41 | mean anything unless on Unix. See the details about those platform |
42 | specifics below. The list of the filenames is returned only if |
43 | $need_names argument is true. |
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44 | |
45 | Dependent libraries can be linked in one of three ways: |
46 | |
47 | =over 2 |
48 | |
49 | =item * For static extensions |
50 | |
51 | by the ld command when the perl binary is linked with the extension |
52 | library. See EXTRALIBS below. |
53 | |
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54 | =item * For dynamic extensions at build/link time |
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55 | |
56 | by the ld command when the shared object is built/linked. See |
57 | LDLOADLIBS below. |
58 | |
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59 | =item * For dynamic extensions at load time |
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60 | |
61 | by the DynaLoader when the shared object is loaded. See BSLOADLIBS |
62 | below. |
63 | |
64 | =back |
65 | |
66 | =head2 EXTRALIBS |
67 | |
68 | List of libraries that need to be linked with when linking a perl |
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69 | binary which includes this extension. Only those libraries that |
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70 | actually exist are included. These are written to a file and used |
71 | when linking perl. |
72 | |
73 | =head2 LDLOADLIBS and LD_RUN_PATH |
74 | |
75 | List of those libraries which can or must be linked into the shared |
76 | library when created using ld. These may be static or dynamic |
77 | libraries. LD_RUN_PATH is a colon separated list of the directories |
78 | in LDLOADLIBS. It is passed as an environment variable to the process |
79 | that links the shared library. |
80 | |
81 | =head2 BSLOADLIBS |
82 | |
83 | List of those libraries that are needed but can be linked in |
84 | dynamically at run time on this platform. SunOS/Solaris does not need |
85 | this because ld records the information (from LDLOADLIBS) into the |
86 | object file. This list is used to create a .bs (bootstrap) file. |
87 | |
88 | =head1 PORTABILITY |
89 | |
90 | This module deals with a lot of system dependencies and has quite a |
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91 | few architecture specific C<if>s in the code. |
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92 | |
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93 | =head2 VMS implementation |
94 | |
95 | The version of ext() which is executed under VMS differs from the |
96 | Unix-OS/2 version in several respects: |
97 | |
98 | =over 2 |
99 | |
100 | =item * |
101 | |
102 | Input library and path specifications are accepted with or without the |
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103 | C<-l> and C<-L> prefixes used by Unix linkers. If neither prefix is |
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104 | present, a token is considered a directory to search if it is in fact |
105 | a directory, and a library to search for otherwise. Authors who wish |
106 | their extensions to be portable to Unix or OS/2 should use the Unix |
107 | prefixes, since the Unix-OS/2 version of ext() requires them. |
108 | |
109 | =item * |
110 | |
111 | Wherever possible, shareable images are preferred to object libraries, |
112 | and object libraries to plain object files. In accordance with VMS |
113 | naming conventions, ext() looks for files named I<lib>shr and I<lib>rtl; |
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114 | it also looks for I<lib>lib and libI<lib> to accommodate Unix conventions |
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115 | used in some ported software. |
116 | |
117 | =item * |
118 | |
119 | For each library that is found, an appropriate directive for a linker options |
120 | file is generated. The return values are space-separated strings of |
121 | these directives, rather than elements used on the linker command line. |
122 | |
123 | =item * |
124 | |
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125 | LDLOADLIBS contains both the libraries found based on C<$potential_libs> and |
126 | the CRTLs, if any, specified in Config.pm. EXTRALIBS contains just those |
127 | libraries found based on C<$potential_libs>. BSLOADLIBS and LD_RUN_PATH |
128 | are always empty. |
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129 | |
130 | =back |
131 | |
132 | In addition, an attempt is made to recognize several common Unix library |
133 | names, and filter them out or convert them to their VMS equivalents, as |
134 | appropriate. |
135 | |
136 | In general, the VMS version of ext() should properly handle input from |
137 | extensions originally designed for a Unix or VMS environment. If you |
138 | encounter problems, or discover cases where the search could be improved, |
139 | please let us know. |
140 | |
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141 | =head2 Win32 implementation |
142 | |
143 | The version of ext() which is executed under Win32 differs from the |
144 | Unix-OS/2 version in several respects: |
145 | |
146 | =over 2 |
147 | |
148 | =item * |
149 | |
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150 | If C<$potential_libs> is empty, the return value will be empty. |
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151 | Otherwise, the libraries specified by C<$Config{perllibs}> (see Config.pm) |
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152 | will be appended to the list of C<$potential_libs>. The libraries |
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153 | will be searched for in the directories specified in C<$potential_libs>, |
154 | C<$Config{libpth}>, and in C<$Config{installarchlib}/CORE>. |
155 | For each library that is found, a space-separated list of fully qualified |
156 | library pathnames is generated. |
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157 | |
158 | =item * |
159 | |
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160 | Input library and path specifications are accepted with or without the |
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161 | C<-l> and C<-L> prefixes used by Unix linkers. |
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162 | |
163 | An entry of the form C<-La:\foo> specifies the C<a:\foo> directory to look |
164 | for the libraries that follow. |
165 | |
166 | An entry of the form C<-lfoo> specifies the library C<foo>, which may be |
167 | spelled differently depending on what kind of compiler you are using. If |
168 | you are using GCC, it gets translated to C<libfoo.a>, but for other win32 |
169 | compilers, it becomes C<foo.lib>. If no files are found by those translated |
170 | names, one more attempt is made to find them using either C<foo.a> or |
171 | C<libfoo.lib>, depending on whether GCC or some other win32 compiler is |
172 | being used, respectively. |
173 | |
174 | If neither the C<-L> or C<-l> prefix is present in an entry, the entry is |
175 | considered a directory to search if it is in fact a directory, and a |
176 | library to search for otherwise. The C<$Config{lib_ext}> suffix will |
177 | be appended to any entries that are not directories and don't already have |
178 | the suffix. |
179 | |
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180 | Note that the C<-L> and C<-l> prefixes are B<not required>, but authors |
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181 | who wish their extensions to be portable to Unix or OS/2 should use the |
182 | prefixes, since the Unix-OS/2 version of ext() requires them. |
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183 | |
184 | =item * |
185 | |
186 | Entries cannot be plain object files, as many Win32 compilers will |
187 | not handle object files in the place of libraries. |
188 | |
189 | =item * |
190 | |
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191 | Entries in C<$potential_libs> beginning with a colon and followed by |
192 | alphanumeric characters are treated as flags. Unknown flags will be ignored. |
193 | |
194 | An entry that matches C</:nodefault/i> disables the appending of default |
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195 | libraries found in C<$Config{perllibs}> (this should be only needed very rarely). |
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196 | |
197 | An entry that matches C</:nosearch/i> disables all searching for |
198 | the libraries specified after it. Translation of C<-Lfoo> and |
199 | C<-lfoo> still happens as appropriate (depending on compiler being used, |
200 | as reflected by C<$Config{cc}>), but the entries are not verified to be |
201 | valid files or directories. |
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202 | |
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203 | An entry that matches C</:search/i> reenables searching for |
204 | the libraries specified after it. You can put it at the end to |
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205 | enable searching for default libraries specified by C<$Config{perllibs}>. |
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206 | |
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207 | =item * |
208 | |
209 | The libraries specified may be a mixture of static libraries and |
210 | import libraries (to link with DLLs). Since both kinds are used |
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211 | pretty transparently on the Win32 platform, we do not attempt to |
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212 | distinguish between them. |
213 | |
214 | =item * |
215 | |
216 | LDLOADLIBS and EXTRALIBS are always identical under Win32, and BSLOADLIBS |
217 | and LD_RUN_PATH are always empty (this may change in future). |
218 | |
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219 | =item * |
220 | |
221 | You must make sure that any paths and path components are properly |
222 | surrounded with double-quotes if they contain spaces. For example, |
223 | C<$potential_libs> could be (literally): |
224 | |
225 | "-Lc:\Program Files\vc\lib" msvcrt.lib "la test\foo bar.lib" |
226 | |
227 | Note how the first and last entries are protected by quotes in order |
228 | to protect the spaces. |
229 | |
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230 | =item * |
231 | |
232 | Since this module is most often used only indirectly from extension |
233 | C<Makefile.PL> files, here is an example C<Makefile.PL> entry to add |
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234 | a library to the build process for an extension: |
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235 | |
236 | LIBS => ['-lgl'] |
237 | |
238 | When using GCC, that entry specifies that MakeMaker should first look |
239 | for C<libgl.a> (followed by C<gl.a>) in all the locations specified by |
240 | C<$Config{libpth}>. |
241 | |
242 | When using a compiler other than GCC, the above entry will search for |
243 | C<gl.lib> (followed by C<libgl.lib>). |
244 | |
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245 | If the library happens to be in a location not in C<$Config{libpth}>, |
246 | you need: |
247 | |
248 | LIBS => ['-Lc:\gllibs -lgl'] |
249 | |
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250 | Here is a less often used example: |
251 | |
252 | LIBS => ['-lgl', ':nosearch -Ld:\mesalibs -lmesa -luser32'] |
253 | |
254 | This specifies a search for library C<gl> as before. If that search |
255 | fails to find the library, it looks at the next item in the list. The |
256 | C<:nosearch> flag will prevent searching for the libraries that follow, |
257 | so it simply returns the value as C<-Ld:\mesalibs -lmesa -luser32>, |
258 | since GCC can use that value as is with its linker. |
259 | |
260 | When using the Visual C compiler, the second item is returned as |
261 | C<-libpath:d:\mesalibs mesa.lib user32.lib>. |
262 | |
263 | When using the Borland compiler, the second item is returned as |
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264 | C<-Ld:\mesalibs mesa.lib user32.lib>, and MakeMaker takes care of |
265 | moving the C<-Ld:\mesalibs> to the correct place in the linker |
266 | command line. |
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267 | |
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268 | =back |
269 | |
270 | |
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271 | =head1 SEE ALSO |
272 | |
273 | L<ExtUtils::MakeMaker> |
274 | |
275 | =cut |
276 | |