This is a live mirror of the Perl 5 development currently hosted at https://github.com/perl/perl5
Liblist tweak suggested by Swen Thuemmler <Swen.Thuemmler@paderlinx.de>;
[perl5.git] / lib / ExtUtils / Liblist.pm
CommitLineData
005c1a0e 1package ExtUtils::Liblist;
8a1da95f 2use vars qw($VERSION);
005c1a0e
AD
3# Broken out of MakeMaker from version 4.11
4
84902520 5$VERSION = substr q$Revision: 1.25 $, 10;
f1387719 6
005c1a0e 7use Config;
8f1aa56b 8use Cwd 'cwd';
4633a7c4
LW
9use File::Basename;
10
005c1a0e 11sub ext {
3e3baf6d
TB
12 if ($^O eq 'VMS') { return &_vms_ext; }
13 elsif($^O eq 'MSWin32') { return &_win32_ext; }
14 else { return &_unix_os2_ext; }
55497cff 15}
16
17sub _unix_os2_ext {
e611f912 18 my($self,$potential_libs, $verbose) = @_;
f1387719 19 if ($^O =~ 'os2' and $Config{libs}) {
4e68a208
AD
20 # Dynamic libraries are not transitive, so we may need including
21 # the libraries linked against perl.dll again.
22
23 $potential_libs .= " " if $potential_libs;
24 $potential_libs .= $Config{libs};
25 }
4633a7c4 26 return ("", "", "", "") unless $potential_libs;
fb73857a 27 warn "Potential libraries are '$potential_libs':\n" if $verbose;
005c1a0e
AD
28
29 my($so) = $Config{'so'};
30 my($libs) = $Config{'libs'};
55497cff 31 my $Config_libext = $Config{lib_ext} || ".a";
32
005c1a0e
AD
33
34 # compute $extralibs, $bsloadlibs and $ldloadlibs from
35 # $potential_libs
36 # this is a rewrite of Andy Dougherty's extliblist in perl
005c1a0e
AD
37
38 my(@searchpath); # from "-L/path" entries in $potential_libs
39 my(@libpath) = split " ", $Config{'libpth'};
4633a7c4 40 my(@ldloadlibs, @bsloadlibs, @extralibs, @ld_run_path, %ld_run_path_seen);
005c1a0e 41 my($fullname, $thislib, $thispth, @fullname);
8f1aa56b 42 my($pwd) = cwd(); # from Cwd.pm
005c1a0e
AD
43 my($found) = 0;
44
45 foreach $thislib (split ' ', $potential_libs){
46
47 # Handle possible linker path arguments.
48 if ($thislib =~ s/^(-[LR])//){ # save path flag type
49 my($ptype) = $1;
50 unless (-d $thislib){
fb73857a 51 warn "$ptype$thislib ignored, directory does not exist\n"
e611f912 52 if $verbose;
005c1a0e
AD
53 next;
54 }
f1387719 55 unless ($self->file_name_is_absolute($thislib)) {
fb73857a 56 warn "Warning: $ptype$thislib changed to $ptype$pwd/$thislib\n";
f1387719 57 $thislib = $self->catdir($pwd,$thislib);
005c1a0e
AD
58 }
59 push(@searchpath, $thislib);
60 push(@extralibs, "$ptype$thislib");
61 push(@ldloadlibs, "$ptype$thislib");
62 next;
63 }
64
65 # Handle possible library arguments.
66 unless ($thislib =~ s/^-l//){
fb73857a 67 warn "Unrecognized argument in LIBS ignored: '$thislib'\n";
005c1a0e
AD
68 next;
69 }
70
71 my($found_lib)=0;
72 foreach $thispth (@searchpath, @libpath){
73
74 # Try to find the full name of the library. We need this to
75 # determine whether it's a dynamically-loadable library or not.
76 # This tends to be subject to various os-specific quirks.
77 # For gcc-2.6.2 on linux (March 1995), DLD can not load
78 # .sa libraries, with the exception of libm.sa, so we
79 # deliberately skip them.
4e1fac24
DM
80 if (@fullname =
81 $self->lsdir($thispth,"^\Qlib$thislib.$so.\E[0-9]+")){
005c1a0e
AD
82 # Take care that libfoo.so.10 wins against libfoo.so.9.
83 # Compare two libraries to find the most recent version
84 # number. E.g. if you have libfoo.so.9.0.7 and
85 # libfoo.so.10.1, first convert all digits into two
86 # decimal places. Then we'll add ".00" to the shorter
87 # strings so that we're comparing strings of equal length
88 # Thus we'll compare libfoo.so.09.07.00 with
89 # libfoo.so.10.01.00. Some libraries might have letters
90 # in the version. We don't know what they mean, but will
91 # try to skip them gracefully -- we'll set any letter to
92 # '0'. Finally, sort in reverse so we can take the
93 # first element.
94
95 #TODO: iterate through the directory instead of sorting
96
97 $fullname = "$thispth/" .
98 (sort { my($ma) = $a;
99 my($mb) = $b;
100 $ma =~ tr/A-Za-z/0/s;
101 $ma =~ s/\b(\d)\b/0$1/g;
102 $mb =~ tr/A-Za-z/0/s;
103 $mb =~ s/\b(\d)\b/0$1/g;
104 while (length($ma) < length($mb)) { $ma .= ".00"; }
105 while (length($mb) < length($ma)) { $mb .= ".00"; }
106 # Comparison deliberately backwards
107 $mb cmp $ma;} @fullname)[0];
108 } elsif (-f ($fullname="$thispth/lib$thislib.$so")
109 && (($Config{'dlsrc'} ne "dl_dld.xs") || ($thislib eq "m"))){
4633a7c4 110 } elsif (-f ($fullname="$thispth/lib${thislib}_s$Config_libext")
005c1a0e 111 && ($thislib .= "_s") ){ # we must explicitly use _s version
4633a7c4 112 } elsif (-f ($fullname="$thispth/lib$thislib$Config_libext")){
864a5fa8 113 } elsif (-f ($fullname="$thispth/$thislib$Config_libext")){
4633a7c4 114 } elsif (-f ($fullname="$thispth/Slib$thislib$Config_libext")){
8f1aa56b 115 } elsif ($^O eq 'dgux'
c07a80fd 116 && -l ($fullname="$thispth/lib$thislib$Config_libext")
117 && readlink($fullname) =~ /^elink:/) {
118 # Some of DG's libraries look like misconnected symbolic
119 # links, but development tools can follow them. (They
120 # look like this:
121 #
122 # libm.a -> elink:${SDE_PATH:-/usr}/sde/\
123 # ${TARGET_BINARY_INTERFACE:-m88kdgux}/usr/lib/libm.a
124 #
125 # , the compilation tools expand the environment variables.)
005c1a0e 126 } else {
fb73857a 127 warn "$thislib not found in $thispth\n" if $verbose;
005c1a0e
AD
128 next;
129 }
fb73857a 130 warn "'-l$thislib' found at $fullname\n" if $verbose;
4633a7c4
LW
131 my($fullnamedir) = dirname($fullname);
132 push @ld_run_path, $fullnamedir unless $ld_run_path_seen{$fullnamedir}++;
005c1a0e
AD
133 $found++;
134 $found_lib++;
135
136 # Now update library lists
137
138 # what do we know about this library...
4633a7c4 139 my $is_dyna = ($fullname !~ /\Q$Config_libext\E$/);
4e68a208 140 my $in_perl = ($libs =~ /\B-l\Q$ {thislib}\E\b/s);
005c1a0e
AD
141
142 # Do not add it into the list if it is already linked in
143 # with the main perl executable.
974f612f 144 # We have to special-case the NeXT, because math and ndbm
145 # are both in libsys_s
005c1a0e 146 unless ($in_perl ||
974f612f 147 ($Config{'osname'} eq 'next' &&
148 ($thislib eq 'm' || $thislib eq 'ndbm')) ){
005c1a0e
AD
149 push(@extralibs, "-l$thislib");
150 }
151
152 # We might be able to load this archive file dynamically
974f612f 153 if ( ($Config{'dlsrc'} =~ /dl_next/ && $Config{'osvers'} lt '4_0')
154 || ($Config{'dlsrc'} =~ /dl_dld/) )
155 {
005c1a0e
AD
156 # We push -l$thislib instead of $fullname because
157 # it avoids hardwiring a fixed path into the .bs file.
158 # Mkbootstrap will automatically add dl_findfile() to
159 # the .bs file if it sees a name in the -l format.
160 # USE THIS, when dl_findfile() is fixed:
161 # push(@bsloadlibs, "-l$thislib");
162 # OLD USE WAS while checking results against old_extliblist
163 push(@bsloadlibs, "$fullname");
164 } else {
165 if ($is_dyna){
166 # For SunOS4, do not add in this shared library if
167 # it is already linked in the main perl executable
168 push(@ldloadlibs, "-l$thislib")
8f1aa56b 169 unless ($in_perl and $^O eq 'sunos');
005c1a0e
AD
170 } else {
171 push(@ldloadlibs, "-l$thislib");
172 }
173 }
174 last; # found one here so don't bother looking further
175 }
fb73857a 176 warn "Note (probably harmless): "
f3d9a6ba 177 ."No library found for -l$thislib\n"
005c1a0e
AD
178 unless $found_lib>0;
179 }
4633a7c4
LW
180 return ('','','','') unless $found;
181 ("@extralibs", "@bsloadlibs", "@ldloadlibs",join(":",@ld_run_path));
005c1a0e
AD
182}
183
3e3baf6d 184sub _win32_ext {
ecc90c0e
GS
185
186 require Text::ParseWords;
187
e611f912 188 my($self, $potential_libs, $verbose) = @_;
3e3baf6d
TB
189
190 # If user did not supply a list, we punt.
191 # (caller should probably use the list in $Config{libs})
192 return ("", "", "", "") unless $potential_libs;
193
944acd49
GS
194 my $cc = $Config{cc};
195 my $VC = 1 if $cc =~ /^cl/i;
196 my $BC = 1 if $cc =~ /^bcc/i;
197 my $GC = 1 if $cc =~ /^gcc/i;
198 my $so = $Config{'so'};
199 my $libs = $Config{'libs'};
200 my $libpth = $Config{'libpth'};
201 my $libext = $Config{'lib_ext'} || ".lib";
3e3baf6d
TB
202
203 if ($libs and $potential_libs !~ /:nodefault/i) {
204 # If Config.pm defines a set of default libs, we always
205 # tack them on to the user-supplied list, unless the user
206 # specified :nodefault
207
208 $potential_libs .= " " if $potential_libs;
209 $potential_libs .= $libs;
210 }
fb73857a 211 warn "Potential libraries are '$potential_libs':\n" if $verbose;
3e3baf6d 212
621ba994
GS
213 # normalize to forward slashes
214 $libpth =~ s,\\,/,g;
215 $potential_libs =~ s,\\,/,g;
216
3e3baf6d
TB
217 # compute $extralibs from $potential_libs
218
944acd49
GS
219 my @searchpath; # from "-L/path" in $potential_libs
220 my @libpath = Text::ParseWords::quotewords('\s+', 0, $libpth);
221 my @extralibs;
222 my $pwd = cwd(); # from Cwd.pm
223 my $lib = '';
224 my $found = 0;
225 my $search = 1;
3e3baf6d 226 my($fullname, $thislib, $thispth);
3e3baf6d 227
b11c3c9f
GS
228 # add "$Config{installarchlib}/CORE" to default search path
229 push @libpath, "$Config{installarchlib}/CORE";
230
944acd49 231 foreach (Text::ParseWords::quotewords('\s+', 0, $potential_libs)){
3e3baf6d 232
944acd49
GS
233 $thislib = $_;
234
235 # see if entry is a flag
236 if (/^:\w+$/) {
237 $search = 0 if lc eq ':nosearch';
238 $search = 1 if lc eq ':search';
239 warn "Ignoring unknown flag '$thislib'\n"
240 if $verbose and !/^:(no)?(search|default)$/i;
241 next;
242 }
243
244 # if searching is disabled, do compiler-specific translations
245 unless ($search) {
944acd49 246 s/^-l(.+)$/$1.lib/ unless $GC;
b11c3c9f 247 s/^-L/-libpath:/ if $VC;
944acd49
GS
248 push(@extralibs, $_);
249 $found++;
250 next;
251 }
252
253 # handle possible linker path arguments
254 if (s/^-L// and not -d) {
255 warn "$thislib ignored, directory does not exist\n"
e611f912 256 if $verbose;
3e3baf6d
TB
257 next;
258 }
944acd49
GS
259 elsif (-d) {
260 unless ($self->file_name_is_absolute($_)) {
261 warn "Warning: '$thislib' changed to '-L$pwd/$_'\n";
262 $_ = $self->catdir($pwd,$_);
3e3baf6d 263 }
944acd49 264 push(@searchpath, $_);
3e3baf6d
TB
265 next;
266 }
267
944acd49
GS
268 # handle possible library arguments
269 if (s/^-l// and $GC and !/^lib/i) {
270 $_ = "lib$_";
2d7a9237 271 }
944acd49
GS
272 $_ .= $libext if !/\Q$libext\E$/i;
273
944acd49 274 my $secondpass = 0;
87de1672 275 LOOKAGAIN:
3e3baf6d 276
d9b182a2 277 # look for the file itself
944acd49
GS
278 if (-f) {
279 warn "'$thislib' found as '$_'\n" if $verbose;
d9b182a2 280 $found++;
944acd49 281 push(@extralibs, $_);
d9b182a2
GS
282 next;
283 }
284
e47a9bbc 285 my $found_lib = 0;
3e3baf6d 286 foreach $thispth (@searchpath, @libpath){
944acd49
GS
287 unless (-f ($fullname="$thispth\\$_")) {
288 warn "'$thislib' not found as '$fullname'\n" if $verbose;
3e3baf6d
TB
289 next;
290 }
944acd49 291 warn "'$thislib' found as '$fullname'\n" if $verbose;
3e3baf6d
TB
292 $found++;
293 $found_lib++;
294 push(@extralibs, $fullname);
295 last;
296 }
944acd49
GS
297
298 # do another pass with (or without) leading 'lib' if they used -l
e47a9bbc
GS
299 if (!$found_lib and $thislib =~ /^-l/ and !$secondpass++) {
300 if ($GC) {
301 goto LOOKAGAIN if s/^lib//i;
302 }
303 elsif (!/^lib/i) {
304 $_ = "lib$_";
305 goto LOOKAGAIN;
306 }
944acd49
GS
307 }
308
309 # give up
fb73857a 310 warn "Note (probably harmless): "
3e3baf6d
TB
311 ."No library found for '$thislib'\n"
312 unless $found_lib>0;
944acd49 313
3e3baf6d 314 }
944acd49 315
3e3baf6d 316 return ('','','','') unless $found;
ecc90c0e
GS
317
318 # make sure paths with spaces are properly quoted
319 @extralibs = map { (/\s/ && !/^".*"$/) ? qq["$_"] : $_ } @extralibs;
3e3baf6d 320 $lib = join(' ',@extralibs);
42ab721c
GS
321
322 # normalize back to backward slashes (to help braindead tools)
323 # XXX this may break equally braindead GNU tools that don't understand
324 # backslashes, either. Seems like one can't win here. Cursed be CP/M.
325 $lib =~ s,/,\\,g;
326
fb73857a 327 warn "Result: $lib\n" if $verbose;
3e3baf6d
TB
328 wantarray ? ($lib, '', $lib, '') : $lib;
329}
330
55497cff 331
332sub _vms_ext {
333 my($self, $potential_libs,$verbose) = @_;
09b7f37c
CB
334 my(@crtls,$crtlstr);
335 my($dbgqual) = $self->{OPTIMIZE} || $Config{'optimize'} ||
336 $self->{CCFLAS} || $Config{'ccflags'};
337 @crtls = ( ($dbgqual =~ m-/Debug-i ? $Config{'dbgprefix'} : '')
338 . 'PerlShr/Share' );
339 push(@crtls, grep { not /\(/ } split /\s+/, $Config{'libs'});
340 push(@crtls, grep { not /\(/ } split /\s+/, $Config{'libc'});
341 # In general, we pass through the basic libraries from %Config unchanged.
342 # The one exception is that if we're building in the Perl source tree, and
343 # a library spec could be resolved via a logical name, we go to some trouble
344 # to insure that the copy in the local tree is used, rather than one to
345 # which a system-wide logical may point.
346 if ($self->{PERL_SRC}) {
347 my($lib,$locspec,$type);
348 foreach $lib (@crtls) {
349 if (($locspec,$type) = $lib =~ m-^([\w$\-]+)(/\w+)?- and $locspec =~ /perl/i) {
350 if (lc $type eq '/share') { $locspec .= $Config{'exe_ext'}; }
351 elsif (lc $type eq '/library') { $locspec .= $Config{'lib_ext'}; }
352 else { $locspec .= $Config{'obj_ext'}; }
353 $locspec = $self->catfile($self->{PERL_SRC},$locspec);
354 $lib = "$locspec$type" if -e $locspec;
355 }
356 }
357 }
358 $crtlstr = @crtls ? join(' ',@crtls) : '';
55497cff 359
09b7f37c
CB
360 unless ($potential_libs) {
361 warn "Result:\n\tEXTRALIBS: \n\tLDLOADLIBS: $crtlstr\n" if $verbose;
362 return ('', '', $crtlstr, '');
363 }
364
365 my(@dirs,@libs,$dir,$lib,%sh,%olb,%obj,$ldlib);
55497cff 366 my $cwd = cwd();
367 my($so,$lib_ext,$obj_ext) = @Config{'so','lib_ext','obj_ext'};
368 # List of common Unix library names and there VMS equivalents
369 # (VMS equivalent of '' indicates that the library is automatially
370 # searched by the linker, and should be skipped here.)
371 my %libmap = ( 'm' => '', 'f77' => '', 'F77' => '', 'V77' => '', 'c' => '',
372 'malloc' => '', 'crypt' => '', 'resolv' => '', 'c_s' => '',
373 'socket' => '', 'X11' => 'DECW$XLIBSHR',
374 'Xt' => 'DECW$XTSHR', 'Xm' => 'DECW$XMLIBSHR',
375 'Xmu' => 'DECW$XMULIBSHR');
376 if ($Config{'vms_cc_type'} ne 'decc') { $libmap{'curses'} = 'VAXCCURSE'; }
377
fb73857a 378 warn "Potential libraries are '$potential_libs'\n" if $verbose;
55497cff 379
380 # First, sort out directories and library names in the input
381 foreach $lib (split ' ',$potential_libs) {
382 push(@dirs,$1), next if $lib =~ /^-L(.*)/;
383 push(@dirs,$lib), next if $lib =~ /[:>\]]$/;
384 push(@dirs,$lib), next if -d $lib;
385 push(@libs,$1), next if $lib =~ /^-l(.*)/;
386 push(@libs,$lib);
387 }
388 push(@dirs,split(' ',$Config{'libpth'}));
389
390 # Now make sure we've got VMS-syntax absolute directory specs
391 # (We don't, however, check whether someone's hidden a relative
392 # path in a logical name.)
393 foreach $dir (@dirs) {
394 unless (-d $dir) {
fb73857a 395 warn "Skipping nonexistent Directory $dir\n" if $verbose > 1;
55497cff 396 $dir = '';
397 next;
398 }
fb73857a 399 warn "Resolving directory $dir\n" if $verbose;
55497cff 400 if ($self->file_name_is_absolute($dir)) { $dir = $self->fixpath($dir,1); }
401 else { $dir = $self->catdir($cwd,$dir); }
402 }
403 @dirs = grep { length($_) } @dirs;
404 unshift(@dirs,''); # Check each $lib without additions first
405
406 LIB: foreach $lib (@libs) {
407 if (exists $libmap{$lib}) {
408 next unless length $libmap{$lib};
409 $lib = $libmap{$lib};
410 }
411
412 my(@variants,$variant,$name,$test,$cand);
413 my($ctype) = '';
414
415 # If we don't have a file type, consider it a possibly abbreviated name and
416 # check for common variants. We try these first to grab libraries before
417 # a like-named executable image (e.g. -lperl resolves to perlshr.exe
418 # before perl.exe).
419 if ($lib !~ /\.[^:>\]]*$/) {
420 push(@variants,"${lib}shr","${lib}rtl","${lib}lib");
421 push(@variants,"lib$lib") if $lib !~ /[:>\]]/;
422 }
423 push(@variants,$lib);
fb73857a 424 warn "Looking for $lib\n" if $verbose;
55497cff 425 foreach $variant (@variants) {
426 foreach $dir (@dirs) {
427 my($type);
428
429 $name = "$dir$variant";
fb73857a 430 warn "\tChecking $name\n" if $verbose > 2;
55497cff 431 if (-f ($test = VMS::Filespec::rmsexpand($name))) {
432 # It's got its own suffix, so we'll have to figure out the type
433 if ($test =~ /(?:$so|exe)$/i) { $type = 'sh'; }
434 elsif ($test =~ /(?:$lib_ext|olb)$/i) { $type = 'olb'; }
435 elsif ($test =~ /(?:$obj_ext|obj)$/i) {
fb73857a 436 warn "Note (probably harmless): "
f3d9a6ba 437 ."Plain object file $test found in library list\n";
55497cff 438 $type = 'obj';
439 }
440 else {
fb73857a 441 warn "Note (probably harmless): "
f3d9a6ba 442 ."Unknown library type for $test; assuming shared\n";
55497cff 443 $type = 'sh';
444 }
445 }
446 elsif (-f ($test = VMS::Filespec::rmsexpand($name,$so)) or
447 -f ($test = VMS::Filespec::rmsexpand($name,'.exe'))) {
448 $type = 'sh';
449 $name = $test unless $test =~ /exe;?\d*$/i;
450 }
451 elsif (not length($ctype) and # If we've got a lib already, don't bother
452 ( -f ($test = VMS::Filespec::rmsexpand($name,$lib_ext)) or
453 -f ($test = VMS::Filespec::rmsexpand($name,'.olb')))) {
454 $type = 'olb';
455 $name = $test unless $test =~ /olb;?\d*$/i;
456 }
457 elsif (not length($ctype) and # If we've got a lib already, don't bother
458 ( -f ($test = VMS::Filespec::rmsexpand($name,$obj_ext)) or
459 -f ($test = VMS::Filespec::rmsexpand($name,'.obj')))) {
fb73857a 460 warn "Note (probably harmless): "
f3d9a6ba 461 ."Plain object file $test found in library list\n";
55497cff 462 $type = 'obj';
463 $name = $test unless $test =~ /obj;?\d*$/i;
464 }
465 if (defined $type) {
466 $ctype = $type; $cand = $name;
467 last if $ctype eq 'sh';
468 }
469 }
470 if ($ctype) {
471 eval '$' . $ctype . "{'$cand'}++";
472 die "Error recording library: $@" if $@;
fb73857a 473 warn "\tFound as $cand (really $test), type $ctype\n" if $verbose > 1;
55497cff 474 next LIB;
475 }
476 }
fb73857a 477 warn "Note (probably harmless): "
f3d9a6ba 478 ."No library found for $lib\n";
55497cff 479 }
480
481 @libs = sort keys %obj;
482 # This has to precede any other CRTLs, so just make it first
483 if ($olb{VAXCCURSE}) {
484 push(@libs,"$olb{VAXCCURSE}/Library");
485 delete $olb{VAXCCURSE};
486 }
487 push(@libs, map { "$_/Library" } sort keys %olb);
488 push(@libs, map { "$_/Share" } sort keys %sh);
489 $lib = join(' ',@libs);
09b7f37c
CB
490
491 $ldlib = $crtlstr ? "$lib $crtlstr" : $lib;
492 warn "Result:\n\tEXTRALIBS: $lib\n\tLDLOADLIBS: $ldlib\n" if $verbose;
493 wantarray ? ($lib, '', $ldlib, '') : $lib;
55497cff 494}
495
005c1a0e 4961;
c2e89b3d 497
864a5fa8 498__END__
cb1a09d0 499
864a5fa8
AD
500=head1 NAME
501
502ExtUtils::Liblist - determine libraries to use and how to use them
503
504=head1 SYNOPSIS
505
506C<require ExtUtils::Liblist;>
507
e611f912 508C<ExtUtils::Liblist::ext($self, $potential_libs, $verbose);>
864a5fa8
AD
509
510=head1 DESCRIPTION
511
512This utility takes a list of libraries in the form C<-llib1 -llib2
513-llib3> and prints out lines suitable for inclusion in an extension
514Makefile. Extra library paths may be included with the form
515C<-L/another/path> this will affect the searches for all subsequent
516libraries.
517
518It returns an array of four scalar values: EXTRALIBS, BSLOADLIBS,
3e3baf6d
TB
519LDLOADLIBS, and LD_RUN_PATH. Some of these don't mean anything
520on VMS and Win32. See the details about those platform specifics
521below.
864a5fa8
AD
522
523Dependent libraries can be linked in one of three ways:
524
525=over 2
526
527=item * For static extensions
528
529by the ld command when the perl binary is linked with the extension
530library. See EXTRALIBS below.
531
532=item * For dynamic extensions
533
534by the ld command when the shared object is built/linked. See
535LDLOADLIBS below.
536
537=item * For dynamic extensions
538
539by the DynaLoader when the shared object is loaded. See BSLOADLIBS
540below.
541
542=back
543
544=head2 EXTRALIBS
545
546List of libraries that need to be linked with when linking a perl
547binary which includes this extension Only those libraries that
548actually exist are included. These are written to a file and used
549when linking perl.
550
551=head2 LDLOADLIBS and LD_RUN_PATH
552
553List of those libraries which can or must be linked into the shared
554library when created using ld. These may be static or dynamic
555libraries. LD_RUN_PATH is a colon separated list of the directories
556in LDLOADLIBS. It is passed as an environment variable to the process
557that links the shared library.
558
559=head2 BSLOADLIBS
560
561List of those libraries that are needed but can be linked in
562dynamically at run time on this platform. SunOS/Solaris does not need
563this because ld records the information (from LDLOADLIBS) into the
564object file. This list is used to create a .bs (bootstrap) file.
565
566=head1 PORTABILITY
567
568This module deals with a lot of system dependencies and has quite a
569few architecture specific B<if>s in the code.
570
55497cff 571=head2 VMS implementation
572
573The version of ext() which is executed under VMS differs from the
574Unix-OS/2 version in several respects:
575
576=over 2
577
578=item *
579
580Input library and path specifications are accepted with or without the
581C<-l> and C<-L> prefices used by Unix linkers. If neither prefix is
582present, a token is considered a directory to search if it is in fact
583a directory, and a library to search for otherwise. Authors who wish
584their extensions to be portable to Unix or OS/2 should use the Unix
585prefixes, since the Unix-OS/2 version of ext() requires them.
586
587=item *
588
589Wherever possible, shareable images are preferred to object libraries,
590and object libraries to plain object files. In accordance with VMS
591naming conventions, ext() looks for files named I<lib>shr and I<lib>rtl;
592it also looks for I<lib>lib and libI<lib> to accomodate Unix conventions
593used in some ported software.
594
595=item *
596
597For each library that is found, an appropriate directive for a linker options
598file is generated. The return values are space-separated strings of
599these directives, rather than elements used on the linker command line.
600
601=item *
602
09b7f37c
CB
603LDLOADLIBS contains both the libraries found based on C<$potential_libs> and
604the CRTLs, if any, specified in Config.pm. EXTRALIBS contains just those
605libraries found based on C<$potential_libs>. BSLOADLIBS and LD_RUN_PATH
606are always empty.
55497cff 607
608=back
609
610In addition, an attempt is made to recognize several common Unix library
611names, and filter them out or convert them to their VMS equivalents, as
612appropriate.
613
614In general, the VMS version of ext() should properly handle input from
615extensions originally designed for a Unix or VMS environment. If you
616encounter problems, or discover cases where the search could be improved,
617please let us know.
618
3e3baf6d
TB
619=head2 Win32 implementation
620
621The version of ext() which is executed under Win32 differs from the
622Unix-OS/2 version in several respects:
623
624=over 2
625
626=item *
627
944acd49
GS
628If C<$potential_libs> is empty, the return value will be empty.
629Otherwise, the libraries specified by C<$Config{libs}> (see Config.pm)
630will be appended to the list of C<$potential_libs>. The libraries
b11c3c9f
GS
631will be searched for in the directories specified in C<$potential_libs>,
632C<$Config{libpth}>, and in C<$Config{installarchlib}/CORE>.
633For each library that is found, a space-separated list of fully qualified
634library pathnames is generated.
944acd49
GS
635
636=item *
637
3e3baf6d 638Input library and path specifications are accepted with or without the
944acd49
GS
639C<-l> and C<-L> prefices used by Unix linkers.
640
641An entry of the form C<-La:\foo> specifies the C<a:\foo> directory to look
642for the libraries that follow.
643
644An entry of the form C<-lfoo> specifies the library C<foo>, which may be
645spelled differently depending on what kind of compiler you are using. If
646you are using GCC, it gets translated to C<libfoo.a>, but for other win32
647compilers, it becomes C<foo.lib>. If no files are found by those translated
648names, one more attempt is made to find them using either C<foo.a> or
649C<libfoo.lib>, depending on whether GCC or some other win32 compiler is
650being used, respectively.
651
652If neither the C<-L> or C<-l> prefix is present in an entry, the entry is
653considered a directory to search if it is in fact a directory, and a
654library to search for otherwise. The C<$Config{lib_ext}> suffix will
655be appended to any entries that are not directories and don't already have
656the suffix.
657
658Note that the C<-L> and <-l> prefixes are B<not required>, but authors
659who wish their extensions to be portable to Unix or OS/2 should use the
660prefixes, since the Unix-OS/2 version of ext() requires them.
3e3baf6d
TB
661
662=item *
663
664Entries cannot be plain object files, as many Win32 compilers will
665not handle object files in the place of libraries.
666
667=item *
668
944acd49
GS
669Entries in C<$potential_libs> beginning with a colon and followed by
670alphanumeric characters are treated as flags. Unknown flags will be ignored.
671
672An entry that matches C</:nodefault/i> disables the appending of default
673libraries found in C<$Config{libs}> (this should be only needed very rarely).
674
675An entry that matches C</:nosearch/i> disables all searching for
676the libraries specified after it. Translation of C<-Lfoo> and
677C<-lfoo> still happens as appropriate (depending on compiler being used,
678as reflected by C<$Config{cc}>), but the entries are not verified to be
679valid files or directories.
3e3baf6d 680
e47a9bbc
GS
681An entry that matches C</:search/i> reenables searching for
682the libraries specified after it. You can put it at the end to
683enable searching for default libraries specified by C<$Config{libs}>.
684
3e3baf6d
TB
685=item *
686
687The libraries specified may be a mixture of static libraries and
688import libraries (to link with DLLs). Since both kinds are used
689pretty transparently on the win32 platform, we do not attempt to
690distinguish between them.
691
692=item *
693
694LDLOADLIBS and EXTRALIBS are always identical under Win32, and BSLOADLIBS
695and LD_RUN_PATH are always empty (this may change in future).
696
ecc90c0e
GS
697=item *
698
699You must make sure that any paths and path components are properly
700surrounded with double-quotes if they contain spaces. For example,
701C<$potential_libs> could be (literally):
702
703 "-Lc:\Program Files\vc\lib" msvcrt.lib "la test\foo bar.lib"
704
705Note how the first and last entries are protected by quotes in order
706to protect the spaces.
707
944acd49
GS
708=item *
709
710Since this module is most often used only indirectly from extension
711C<Makefile.PL> files, here is an example C<Makefile.PL> entry to add
e47a9bbc 712a library to the build process for an extension:
944acd49
GS
713
714 LIBS => ['-lgl']
715
716When using GCC, that entry specifies that MakeMaker should first look
717for C<libgl.a> (followed by C<gl.a>) in all the locations specified by
718C<$Config{libpth}>.
719
720When using a compiler other than GCC, the above entry will search for
721C<gl.lib> (followed by C<libgl.lib>).
722
e47a9bbc
GS
723If the library happens to be in a location not in C<$Config{libpth}>,
724you need:
725
726 LIBS => ['-Lc:\gllibs -lgl']
727
944acd49
GS
728Here is a less often used example:
729
730 LIBS => ['-lgl', ':nosearch -Ld:\mesalibs -lmesa -luser32']
731
732This specifies a search for library C<gl> as before. If that search
733fails to find the library, it looks at the next item in the list. The
734C<:nosearch> flag will prevent searching for the libraries that follow,
735so it simply returns the value as C<-Ld:\mesalibs -lmesa -luser32>,
736since GCC can use that value as is with its linker.
737
738When using the Visual C compiler, the second item is returned as
739C<-libpath:d:\mesalibs mesa.lib user32.lib>.
740
741When using the Borland compiler, the second item is returned as
e47a9bbc
GS
742C<-Ld:\mesalibs mesa.lib user32.lib>, and MakeMaker takes care of
743moving the C<-Ld:\mesalibs> to the correct place in the linker
744command line.
944acd49 745
3e3baf6d
TB
746=back
747
748
864a5fa8
AD
749=head1 SEE ALSO
750
751L<ExtUtils::MakeMaker>
752
753=cut
754