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