1 package ExtUtils::Liblist;
4 # Broken out of MakeMaker from version 4.11
6 our $VERSION = substr q$Revision: 1.25 $, 10;
13 if ($^O eq 'VMS') { return &_vms_ext; }
14 elsif($^O eq 'MSWin32') { return &_win32_ext; }
15 else { return &_unix_os2_ext; }
19 my($self,$potential_libs, $verbose) = @_;
20 if ($^O =~ 'os2' and $Config{libs}) {
21 # Dynamic libraries are not transitive, so we may need including
22 # the libraries linked against perl.dll again.
24 $potential_libs .= " " if $potential_libs;
25 $potential_libs .= $Config{libs};
27 return ("", "", "", "") unless $potential_libs;
28 warn "Potential libraries are '$potential_libs':\n" if $verbose;
30 my($so) = $Config{'so'};
31 my($libs) = $Config{'libs'};
32 my $Config_libext = $Config{lib_ext} || ".a";
35 # compute $extralibs, $bsloadlibs and $ldloadlibs from
37 # this is a rewrite of Andy Dougherty's extliblist in perl
39 my(@searchpath); # from "-L/path" entries in $potential_libs
40 my(@libpath) = split " ", $Config{'libpth'};
41 my(@ldloadlibs, @bsloadlibs, @extralibs, @ld_run_path, %ld_run_path_seen);
42 my($fullname, $thislib, $thispth, @fullname);
43 my($pwd) = cwd(); # from Cwd.pm
46 foreach $thislib (split ' ', $potential_libs){
48 # Handle possible linker path arguments.
49 if ($thislib =~ s/^(-[LR])//){ # save path flag type
52 warn "$ptype$thislib ignored, directory does not exist\n"
56 unless ($self->file_name_is_absolute($thislib)) {
57 warn "Warning: $ptype$thislib changed to $ptype$pwd/$thislib\n";
58 $thislib = $self->catdir($pwd,$thislib);
60 push(@searchpath, $thislib);
61 push(@extralibs, "$ptype$thislib");
62 push(@ldloadlibs, "$ptype$thislib");
66 # Handle possible library arguments.
67 unless ($thislib =~ s/^-l//){
68 warn "Unrecognized argument in LIBS ignored: '$thislib'\n";
73 foreach $thispth (@searchpath, @libpath){
75 # Try to find the full name of the library. We need this to
76 # determine whether it's a dynamically-loadable library or not.
77 # This tends to be subject to various os-specific quirks.
78 # For gcc-2.6.2 on linux (March 1995), DLD can not load
79 # .sa libraries, with the exception of libm.sa, so we
80 # deliberately skip them.
82 $self->lsdir($thispth,"^\Qlib$thislib.$so.\E[0-9]+")){
83 # Take care that libfoo.so.10 wins against libfoo.so.9.
84 # Compare two libraries to find the most recent version
85 # number. E.g. if you have libfoo.so.9.0.7 and
86 # libfoo.so.10.1, first convert all digits into two
87 # decimal places. Then we'll add ".00" to the shorter
88 # strings so that we're comparing strings of equal length
89 # Thus we'll compare libfoo.so.09.07.00 with
90 # libfoo.so.10.01.00. Some libraries might have letters
91 # in the version. We don't know what they mean, but will
92 # try to skip them gracefully -- we'll set any letter to
93 # '0'. Finally, sort in reverse so we can take the
96 #TODO: iterate through the directory instead of sorting
98 $fullname = "$thispth/" .
101 $ma =~ tr/A-Za-z/0/s;
102 $ma =~ s/\b(\d)\b/0$1/g;
103 $mb =~ tr/A-Za-z/0/s;
104 $mb =~ s/\b(\d)\b/0$1/g;
105 while (length($ma) < length($mb)) { $ma .= ".00"; }
106 while (length($mb) < length($ma)) { $mb .= ".00"; }
107 # Comparison deliberately backwards
108 $mb cmp $ma;} @fullname)[0];
109 } elsif (-f ($fullname="$thispth/lib$thislib.$so")
110 && (($Config{'dlsrc'} ne "dl_dld.xs") || ($thislib eq "m"))){
111 } elsif (-f ($fullname="$thispth/lib${thislib}_s$Config_libext")
112 && ($thislib .= "_s") ){ # we must explicitly use _s version
113 } elsif (-f ($fullname="$thispth/lib$thislib$Config_libext")){
114 } elsif (-f ($fullname="$thispth/$thislib$Config_libext")){
115 } elsif (-f ($fullname="$thispth/Slib$thislib$Config_libext")){
116 } elsif ($^O eq 'dgux'
117 && -l ($fullname="$thispth/lib$thislib$Config_libext")
118 && readlink($fullname) =~ /^elink:/) {
119 # Some of DG's libraries look like misconnected symbolic
120 # links, but development tools can follow them. (They
123 # libm.a -> elink:${SDE_PATH:-/usr}/sde/\
124 # ${TARGET_BINARY_INTERFACE:-m88kdgux}/usr/lib/libm.a
126 # , the compilation tools expand the environment variables.)
128 warn "$thislib not found in $thispth\n" if $verbose;
131 warn "'-l$thislib' found at $fullname\n" if $verbose;
132 my($fullnamedir) = dirname($fullname);
133 push @ld_run_path, $fullnamedir unless $ld_run_path_seen{$fullnamedir}++;
137 # Now update library lists
139 # what do we know about this library...
140 my $is_dyna = ($fullname !~ /\Q$Config_libext\E$/);
141 my $in_perl = ($libs =~ /\B-l\Q$ {thislib}\E\b/s);
143 # Do not add it into the list if it is already linked in
144 # with the main perl executable.
145 # We have to special-case the NeXT, because math and ndbm
146 # are both in libsys_s
148 ($Config{'osname'} eq 'next' &&
149 ($thislib eq 'm' || $thislib eq 'ndbm')) ){
150 push(@extralibs, "-l$thislib");
153 # We might be able to load this archive file dynamically
154 if ( ($Config{'dlsrc'} =~ /dl_next/ && $Config{'osvers'} lt '4_0')
155 || ($Config{'dlsrc'} =~ /dl_dld/) )
157 # We push -l$thislib instead of $fullname because
158 # it avoids hardwiring a fixed path into the .bs file.
159 # Mkbootstrap will automatically add dl_findfile() to
160 # the .bs file if it sees a name in the -l format.
161 # USE THIS, when dl_findfile() is fixed:
162 # push(@bsloadlibs, "-l$thislib");
163 # OLD USE WAS while checking results against old_extliblist
164 push(@bsloadlibs, "$fullname");
167 # For SunOS4, do not add in this shared library if
168 # it is already linked in the main perl executable
169 push(@ldloadlibs, "-l$thislib")
170 unless ($in_perl and $^O eq 'sunos');
172 push(@ldloadlibs, "-l$thislib");
175 last; # found one here so don't bother looking further
177 warn "Note (probably harmless): "
178 ."No library found for -l$thislib\n"
181 return ('','','','') unless $found;
182 ("@extralibs", "@bsloadlibs", "@ldloadlibs",join(":",@ld_run_path));
187 require Text::ParseWords;
189 my($self, $potential_libs, $verbose) = @_;
191 # If user did not supply a list, we punt.
192 # (caller should probably use the list in $Config{libs})
193 return ("", "", "", "") unless $potential_libs;
195 my $cc = $Config{cc};
196 my $VC = 1 if $cc =~ /^cl/i;
197 my $BC = 1 if $cc =~ /^bcc/i;
198 my $GC = 1 if $cc =~ /^gcc/i;
199 my $so = $Config{'so'};
200 my $libs = $Config{'libs'};
201 my $libpth = $Config{'libpth'};
202 my $libext = $Config{'lib_ext'} || ".lib";
204 if ($libs and $potential_libs !~ /:nodefault/i) {
205 # If Config.pm defines a set of default libs, we always
206 # tack them on to the user-supplied list, unless the user
207 # specified :nodefault
209 $potential_libs .= " " if $potential_libs;
210 $potential_libs .= $libs;
212 warn "Potential libraries are '$potential_libs':\n" if $verbose;
214 # normalize to forward slashes
216 $potential_libs =~ s,\\,/,g;
218 # compute $extralibs from $potential_libs
220 my @searchpath; # from "-L/path" in $potential_libs
221 my @libpath = Text::ParseWords::quotewords('\s+', 0, $libpth);
223 my $pwd = cwd(); # from Cwd.pm
227 my($fullname, $thislib, $thispth);
229 # add "$Config{installarchlib}/CORE" to default search path
230 push @libpath, "$Config{installarchlib}/CORE";
232 foreach (Text::ParseWords::quotewords('\s+', 0, $potential_libs)){
236 # see if entry is a flag
238 $search = 0 if lc eq ':nosearch';
239 $search = 1 if lc eq ':search';
240 warn "Ignoring unknown flag '$thislib'\n"
241 if $verbose and !/^:(no)?(search|default)$/i;
245 # if searching is disabled, do compiler-specific translations
247 s/^-l(.+)$/$1.lib/ unless $GC;
248 s/^-L/-libpath:/ if $VC;
249 push(@extralibs, $_);
254 # handle possible linker path arguments
255 if (s/^-L// and not -d) {
256 warn "$thislib ignored, directory does not exist\n"
261 unless ($self->file_name_is_absolute($_)) {
262 warn "Warning: '$thislib' changed to '-L$pwd/$_'\n";
263 $_ = $self->catdir($pwd,$_);
265 push(@searchpath, $_);
269 # handle possible library arguments
270 if (s/^-l// and $GC and !/^lib/i) {
273 $_ .= $libext if !/\Q$libext\E$/i;
278 # look for the file itself
280 warn "'$thislib' found as '$_'\n" if $verbose;
282 push(@extralibs, $_);
287 foreach $thispth (@searchpath, @libpath){
288 unless (-f ($fullname="$thispth\\$_")) {
289 warn "'$thislib' not found as '$fullname'\n" if $verbose;
292 warn "'$thislib' found as '$fullname'\n" if $verbose;
295 push(@extralibs, $fullname);
299 # do another pass with (or without) leading 'lib' if they used -l
300 if (!$found_lib and $thislib =~ /^-l/ and !$secondpass++) {
302 goto LOOKAGAIN if s/^lib//i;
311 warn "Note (probably harmless): "
312 ."No library found for '$thislib'\n"
317 return ('','','','') unless $found;
319 # make sure paths with spaces are properly quoted
320 @extralibs = map { (/\s/ && !/^".*"$/) ? qq["$_"] : $_ } @extralibs;
321 $lib = join(' ',@extralibs);
323 # normalize back to backward slashes (to help braindead tools)
324 # XXX this may break equally braindead GNU tools that don't understand
325 # backslashes, either. Seems like one can't win here. Cursed be CP/M.
328 warn "Result: $lib\n" if $verbose;
329 wantarray ? ($lib, '', $lib, '') : $lib;
334 my($self, $potential_libs,$verbose) = @_;
336 my($dbgqual) = $self->{OPTIMIZE} || $Config{'optimize'} ||
337 $self->{CCFLAS} || $Config{'ccflags'};
338 @crtls = ( ($dbgqual =~ m-/Debug-i ? $Config{'dbgprefix'} : '')
340 push(@crtls, grep { not /\(/ } split /\s+/, $Config{'libs'});
341 push(@crtls, grep { not /\(/ } split /\s+/, $Config{'libc'});
342 # In general, we pass through the basic libraries from %Config unchanged.
343 # The one exception is that if we're building in the Perl source tree, and
344 # a library spec could be resolved via a logical name, we go to some trouble
345 # to insure that the copy in the local tree is used, rather than one to
346 # which a system-wide logical may point.
347 if ($self->{PERL_SRC}) {
348 my($lib,$locspec,$type);
349 foreach $lib (@crtls) {
350 if (($locspec,$type) = $lib =~ m-^([\w$\-]+)(/\w+)?- and $locspec =~ /perl/i) {
351 if (lc $type eq '/share') { $locspec .= $Config{'exe_ext'}; }
352 elsif (lc $type eq '/library') { $locspec .= $Config{'lib_ext'}; }
353 else { $locspec .= $Config{'obj_ext'}; }
354 $locspec = $self->catfile($self->{PERL_SRC},$locspec);
355 $lib = "$locspec$type" if -e $locspec;
359 $crtlstr = @crtls ? join(' ',@crtls) : '';
361 unless ($potential_libs) {
362 warn "Result:\n\tEXTRALIBS: \n\tLDLOADLIBS: $crtlstr\n" if $verbose;
363 return ('', '', $crtlstr, '');
366 my(@dirs,@libs,$dir,$lib,%found,@fndlibs,$ldlib);
368 my($so,$lib_ext,$obj_ext) = @Config{'so','lib_ext','obj_ext'};
369 # List of common Unix library names and there VMS equivalents
370 # (VMS equivalent of '' indicates that the library is automatially
371 # searched by the linker, and should be skipped here.)
372 my %libmap = ( 'm' => '', 'f77' => '', 'F77' => '', 'V77' => '', 'c' => '',
373 'malloc' => '', 'crypt' => '', 'resolv' => '', 'c_s' => '',
374 'socket' => '', 'X11' => 'DECW$XLIBSHR',
375 'Xt' => 'DECW$XTSHR', 'Xm' => 'DECW$XMLIBSHR',
376 'Xmu' => 'DECW$XMULIBSHR');
377 if ($Config{'vms_cc_type'} ne 'decc') { $libmap{'curses'} = 'VAXCCURSE'; }
379 warn "Potential libraries are '$potential_libs'\n" if $verbose;
381 # First, sort out directories and library names in the input
382 foreach $lib (split ' ',$potential_libs) {
383 push(@dirs,$1), next if $lib =~ /^-L(.*)/;
384 push(@dirs,$lib), next if $lib =~ /[:>\]]$/;
385 push(@dirs,$lib), next if -d $lib;
386 push(@libs,$1), next if $lib =~ /^-l(.*)/;
389 push(@dirs,split(' ',$Config{'libpth'}));
391 # Now make sure we've got VMS-syntax absolute directory specs
392 # (We don't, however, check whether someone's hidden a relative
393 # path in a logical name.)
394 foreach $dir (@dirs) {
396 warn "Skipping nonexistent Directory $dir\n" if $verbose > 1;
400 warn "Resolving directory $dir\n" if $verbose;
401 if ($self->file_name_is_absolute($dir)) { $dir = $self->fixpath($dir,1); }
402 else { $dir = $self->catdir($cwd,$dir); }
404 @dirs = grep { length($_) } @dirs;
405 unshift(@dirs,''); # Check each $lib without additions first
407 LIB: foreach $lib (@libs) {
408 if (exists $libmap{$lib}) {
409 next unless length $libmap{$lib};
410 $lib = $libmap{$lib};
413 my(@variants,$variant,$name,$test,$cand);
416 # If we don't have a file type, consider it a possibly abbreviated name and
417 # check for common variants. We try these first to grab libraries before
418 # a like-named executable image (e.g. -lperl resolves to perlshr.exe
420 if ($lib !~ /\.[^:>\]]*$/) {
421 push(@variants,"${lib}shr","${lib}rtl","${lib}lib");
422 push(@variants,"lib$lib") if $lib !~ /[:>\]]/;
424 push(@variants,$lib);
425 warn "Looking for $lib\n" if $verbose;
426 foreach $variant (@variants) {
427 foreach $dir (@dirs) {
430 $name = "$dir$variant";
431 warn "\tChecking $name\n" if $verbose > 2;
432 if (-f ($test = VMS::Filespec::rmsexpand($name))) {
433 # It's got its own suffix, so we'll have to figure out the type
434 if ($test =~ /(?:$so|exe)$/i) { $type = 'SHR'; }
435 elsif ($test =~ /(?:$lib_ext|olb)$/i) { $type = 'OLB'; }
436 elsif ($test =~ /(?:$obj_ext|obj)$/i) {
437 warn "Note (probably harmless): "
438 ."Plain object file $test found in library list\n";
442 warn "Note (probably harmless): "
443 ."Unknown library type for $test; assuming shared\n";
447 elsif (-f ($test = VMS::Filespec::rmsexpand($name,$so)) or
448 -f ($test = VMS::Filespec::rmsexpand($name,'.exe'))) {
450 $name = $test unless $test =~ /exe;?\d*$/i;
452 elsif (not length($ctype) and # If we've got a lib already, don't bother
453 ( -f ($test = VMS::Filespec::rmsexpand($name,$lib_ext)) or
454 -f ($test = VMS::Filespec::rmsexpand($name,'.olb')))) {
456 $name = $test unless $test =~ /olb;?\d*$/i;
458 elsif (not length($ctype) and # If we've got a lib already, don't bother
459 ( -f ($test = VMS::Filespec::rmsexpand($name,$obj_ext)) or
460 -f ($test = VMS::Filespec::rmsexpand($name,'.obj')))) {
461 warn "Note (probably harmless): "
462 ."Plain object file $test found in library list\n";
464 $name = $test unless $test =~ /obj;?\d*$/i;
467 $ctype = $type; $cand = $name;
468 last if $ctype eq 'SHR';
472 # This has to precede any other CRTLs, so just make it first
473 if ($cand eq 'VAXCCURSE') { unshift @{$found{$ctype}}, $cand; }
474 else { push @{$found{$ctype}}, $cand; }
475 warn "\tFound as $cand (really $test), type $ctype\n" if $verbose > 1;
479 warn "Note (probably harmless): "
480 ."No library found for $lib\n";
483 push @fndlibs, @{$found{OBJ}} if exists $found{OBJ};
484 push @fndlibs, map { "$_/Library" } @{$found{OLB}} if exists $found{OLB};
485 push @fndlibs, map { "$_/Share" } @{$found{SHR}} if exists $found{SHR};
486 $lib = join(' ',@fndlibs);
488 $ldlib = $crtlstr ? "$lib $crtlstr" : $lib;
489 warn "Result:\n\tEXTRALIBS: $lib\n\tLDLOADLIBS: $ldlib\n" if $verbose;
490 wantarray ? ($lib, '', $ldlib, '') : $lib;
499 ExtUtils::Liblist - determine libraries to use and how to use them
503 C<require ExtUtils::Liblist;>
505 C<ExtUtils::Liblist::ext($self, $potential_libs, $verbose);>
509 This utility takes a list of libraries in the form C<-llib1 -llib2
510 -llib3> and prints out lines suitable for inclusion in an extension
511 Makefile. Extra library paths may be included with the form
512 C<-L/another/path> this will affect the searches for all subsequent
515 It returns an array of four scalar values: EXTRALIBS, BSLOADLIBS,
516 LDLOADLIBS, and LD_RUN_PATH. Some of these don't mean anything
517 on VMS and Win32. See the details about those platform specifics
520 Dependent libraries can be linked in one of three ways:
524 =item * For static extensions
526 by the ld command when the perl binary is linked with the extension
527 library. See EXTRALIBS below.
529 =item * For dynamic extensions
531 by the ld command when the shared object is built/linked. See
534 =item * For dynamic extensions
536 by the DynaLoader when the shared object is loaded. See BSLOADLIBS
543 List of libraries that need to be linked with when linking a perl
544 binary which includes this extension. Only those libraries that
545 actually exist are included. These are written to a file and used
548 =head2 LDLOADLIBS and LD_RUN_PATH
550 List of those libraries which can or must be linked into the shared
551 library when created using ld. These may be static or dynamic
552 libraries. LD_RUN_PATH is a colon separated list of the directories
553 in LDLOADLIBS. It is passed as an environment variable to the process
554 that links the shared library.
558 List of those libraries that are needed but can be linked in
559 dynamically at run time on this platform. SunOS/Solaris does not need
560 this because ld records the information (from LDLOADLIBS) into the
561 object file. This list is used to create a .bs (bootstrap) file.
565 This module deals with a lot of system dependencies and has quite a
566 few architecture specific C<if>s in the code.
568 =head2 VMS implementation
570 The version of ext() which is executed under VMS differs from the
571 Unix-OS/2 version in several respects:
577 Input library and path specifications are accepted with or without the
578 C<-l> and C<-L> prefixes used by Unix linkers. If neither prefix is
579 present, a token is considered a directory to search if it is in fact
580 a directory, and a library to search for otherwise. Authors who wish
581 their extensions to be portable to Unix or OS/2 should use the Unix
582 prefixes, since the Unix-OS/2 version of ext() requires them.
586 Wherever possible, shareable images are preferred to object libraries,
587 and object libraries to plain object files. In accordance with VMS
588 naming conventions, ext() looks for files named I<lib>shr and I<lib>rtl;
589 it also looks for I<lib>lib and libI<lib> to accommodate Unix conventions
590 used in some ported software.
594 For each library that is found, an appropriate directive for a linker options
595 file is generated. The return values are space-separated strings of
596 these directives, rather than elements used on the linker command line.
600 LDLOADLIBS contains both the libraries found based on C<$potential_libs> and
601 the CRTLs, if any, specified in Config.pm. EXTRALIBS contains just those
602 libraries found based on C<$potential_libs>. BSLOADLIBS and LD_RUN_PATH
607 In addition, an attempt is made to recognize several common Unix library
608 names, and filter them out or convert them to their VMS equivalents, as
611 In general, the VMS version of ext() should properly handle input from
612 extensions originally designed for a Unix or VMS environment. If you
613 encounter problems, or discover cases where the search could be improved,
616 =head2 Win32 implementation
618 The version of ext() which is executed under Win32 differs from the
619 Unix-OS/2 version in several respects:
625 If C<$potential_libs> is empty, the return value will be empty.
626 Otherwise, the libraries specified by C<$Config{libs}> (see Config.pm)
627 will be appended to the list of C<$potential_libs>. The libraries
628 will be searched for in the directories specified in C<$potential_libs>,
629 C<$Config{libpth}>, and in C<$Config{installarchlib}/CORE>.
630 For each library that is found, a space-separated list of fully qualified
631 library pathnames is generated.
635 Input library and path specifications are accepted with or without the
636 C<-l> and C<-L> prefixes used by Unix linkers.
638 An entry of the form C<-La:\foo> specifies the C<a:\foo> directory to look
639 for the libraries that follow.
641 An entry of the form C<-lfoo> specifies the library C<foo>, which may be
642 spelled differently depending on what kind of compiler you are using. If
643 you are using GCC, it gets translated to C<libfoo.a>, but for other win32
644 compilers, it becomes C<foo.lib>. If no files are found by those translated
645 names, one more attempt is made to find them using either C<foo.a> or
646 C<libfoo.lib>, depending on whether GCC or some other win32 compiler is
647 being used, respectively.
649 If neither the C<-L> or C<-l> prefix is present in an entry, the entry is
650 considered a directory to search if it is in fact a directory, and a
651 library to search for otherwise. The C<$Config{lib_ext}> suffix will
652 be appended to any entries that are not directories and don't already have
655 Note that the C<-L> and C<-l> prefixes are B<not required>, but authors
656 who wish their extensions to be portable to Unix or OS/2 should use the
657 prefixes, since the Unix-OS/2 version of ext() requires them.
661 Entries cannot be plain object files, as many Win32 compilers will
662 not handle object files in the place of libraries.
666 Entries in C<$potential_libs> beginning with a colon and followed by
667 alphanumeric characters are treated as flags. Unknown flags will be ignored.
669 An entry that matches C</:nodefault/i> disables the appending of default
670 libraries found in C<$Config{libs}> (this should be only needed very rarely).
672 An entry that matches C</:nosearch/i> disables all searching for
673 the libraries specified after it. Translation of C<-Lfoo> and
674 C<-lfoo> still happens as appropriate (depending on compiler being used,
675 as reflected by C<$Config{cc}>), but the entries are not verified to be
676 valid files or directories.
678 An entry that matches C</:search/i> reenables searching for
679 the libraries specified after it. You can put it at the end to
680 enable searching for default libraries specified by C<$Config{libs}>.
684 The libraries specified may be a mixture of static libraries and
685 import libraries (to link with DLLs). Since both kinds are used
686 pretty transparently on the Win32 platform, we do not attempt to
687 distinguish between them.
691 LDLOADLIBS and EXTRALIBS are always identical under Win32, and BSLOADLIBS
692 and LD_RUN_PATH are always empty (this may change in future).
696 You must make sure that any paths and path components are properly
697 surrounded with double-quotes if they contain spaces. For example,
698 C<$potential_libs> could be (literally):
700 "-Lc:\Program Files\vc\lib" msvcrt.lib "la test\foo bar.lib"
702 Note how the first and last entries are protected by quotes in order
703 to protect the spaces.
707 Since this module is most often used only indirectly from extension
708 C<Makefile.PL> files, here is an example C<Makefile.PL> entry to add
709 a library to the build process for an extension:
713 When using GCC, that entry specifies that MakeMaker should first look
714 for C<libgl.a> (followed by C<gl.a>) in all the locations specified by
717 When using a compiler other than GCC, the above entry will search for
718 C<gl.lib> (followed by C<libgl.lib>).
720 If the library happens to be in a location not in C<$Config{libpth}>,
723 LIBS => ['-Lc:\gllibs -lgl']
725 Here is a less often used example:
727 LIBS => ['-lgl', ':nosearch -Ld:\mesalibs -lmesa -luser32']
729 This specifies a search for library C<gl> as before. If that search
730 fails to find the library, it looks at the next item in the list. The
731 C<:nosearch> flag will prevent searching for the libraries that follow,
732 so it simply returns the value as C<-Ld:\mesalibs -lmesa -luser32>,
733 since GCC can use that value as is with its linker.
735 When using the Visual C compiler, the second item is returned as
736 C<-libpath:d:\mesalibs mesa.lib user32.lib>.
738 When using the Borland compiler, the second item is returned as
739 C<-Ld:\mesalibs mesa.lib user32.lib>, and MakeMaker takes care of
740 moving the C<-Ld:\mesalibs> to the correct place in the linker
748 L<ExtUtils::MakeMaker>