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Diffstat (limited to 'contrib/perl5/lib/ExtUtils/Liblist.pm')
| -rw-r--r-- | contrib/perl5/lib/ExtUtils/Liblist.pm | 750 |
1 files changed, 750 insertions, 0 deletions
diff --git a/contrib/perl5/lib/ExtUtils/Liblist.pm b/contrib/perl5/lib/ExtUtils/Liblist.pm new file mode 100644 index 0000000..b072c12 --- /dev/null +++ b/contrib/perl5/lib/ExtUtils/Liblist.pm @@ -0,0 +1,750 @@ +package ExtUtils::Liblist; +use vars qw($VERSION); +# Broken out of MakeMaker from version 4.11 + +$VERSION = substr q$Revision: 1.25 $, 10; + +use Config; +use Cwd 'cwd'; +use File::Basename; + +sub ext { + if ($^O eq 'VMS') { return &_vms_ext; } + elsif($^O eq 'MSWin32') { return &_win32_ext; } + else { return &_unix_os2_ext; } +} + +sub _unix_os2_ext { + my($self,$potential_libs, $verbose) = @_; + if ($^O =~ 'os2' and $Config{libs}) { + # Dynamic libraries are not transitive, so we may need including + # the libraries linked against perl.dll again. + + $potential_libs .= " " if $potential_libs; + $potential_libs .= $Config{libs}; + } + return ("", "", "", "") unless $potential_libs; + warn "Potential libraries are '$potential_libs':\n" if $verbose; + + my($so) = $Config{'so'}; + my($libs) = $Config{'libs'}; + my $Config_libext = $Config{lib_ext} || ".a"; + + + # compute $extralibs, $bsloadlibs and $ldloadlibs from + # $potential_libs + # this is a rewrite of Andy Dougherty's extliblist in perl + + my(@searchpath); # from "-L/path" entries in $potential_libs + my(@libpath) = split " ", $Config{'libpth'}; + my(@ldloadlibs, @bsloadlibs, @extralibs, @ld_run_path, %ld_run_path_seen); + my($fullname, $thislib, $thispth, @fullname); + my($pwd) = cwd(); # from Cwd.pm + my($found) = 0; + + foreach $thislib (split ' ', $potential_libs){ + + # Handle possible linker path arguments. + if ($thislib =~ s/^(-[LR])//){ # save path flag type + my($ptype) = $1; + unless (-d $thislib){ + warn "$ptype$thislib ignored, directory does not exist\n" + if $verbose; + next; + } + unless ($self->file_name_is_absolute($thislib)) { + warn "Warning: $ptype$thislib changed to $ptype$pwd/$thislib\n"; + $thislib = $self->catdir($pwd,$thislib); + } + push(@searchpath, $thislib); + push(@extralibs, "$ptype$thislib"); + push(@ldloadlibs, "$ptype$thislib"); + next; + } + + # Handle possible library arguments. + unless ($thislib =~ s/^-l//){ + warn "Unrecognized argument in LIBS ignored: '$thislib'\n"; + next; + } + + my($found_lib)=0; + foreach $thispth (@searchpath, @libpath){ + + # Try to find the full name of the library. We need this to + # determine whether it's a dynamically-loadable library or not. + # This tends to be subject to various os-specific quirks. + # For gcc-2.6.2 on linux (March 1995), DLD can not load + # .sa libraries, with the exception of libm.sa, so we + # deliberately skip them. + if (@fullname = + $self->lsdir($thispth,"^\Qlib$thislib.$so.\E[0-9]+")){ + # Take care that libfoo.so.10 wins against libfoo.so.9. + # Compare two libraries to find the most recent version + # number. E.g. if you have libfoo.so.9.0.7 and + # libfoo.so.10.1, first convert all digits into two + # decimal places. Then we'll add ".00" to the shorter + # strings so that we're comparing strings of equal length + # Thus we'll compare libfoo.so.09.07.00 with + # libfoo.so.10.01.00. Some libraries might have letters + # in the version. We don't know what they mean, but will + # try to skip them gracefully -- we'll set any letter to + # '0'. Finally, sort in reverse so we can take the + # first element. + + #TODO: iterate through the directory instead of sorting + + $fullname = "$thispth/" . + (sort { my($ma) = $a; + my($mb) = $b; + $ma =~ tr/A-Za-z/0/s; + $ma =~ s/\b(\d)\b/0$1/g; + $mb =~ tr/A-Za-z/0/s; + $mb =~ s/\b(\d)\b/0$1/g; + while (length($ma) < length($mb)) { $ma .= ".00"; } + while (length($mb) < length($ma)) { $mb .= ".00"; } + # Comparison deliberately backwards + $mb cmp $ma;} @fullname)[0]; + } elsif (-f ($fullname="$thispth/lib$thislib.$so") + && (($Config{'dlsrc'} ne "dl_dld.xs") || ($thislib eq "m"))){ + } elsif (-f ($fullname="$thispth/lib${thislib}_s$Config_libext") + && ($thislib .= "_s") ){ # we must explicitly use _s version + } elsif (-f ($fullname="$thispth/lib$thislib$Config_libext")){ + } elsif (-f ($fullname="$thispth/$thislib$Config_libext")){ + } elsif (-f ($fullname="$thispth/Slib$thislib$Config_libext")){ + } elsif ($^O eq 'dgux' + && -l ($fullname="$thispth/lib$thislib$Config_libext") + && readlink($fullname) =~ /^elink:/) { + # Some of DG's libraries look like misconnected symbolic + # links, but development tools can follow them. (They + # look like this: + # + # libm.a -> elink:${SDE_PATH:-/usr}/sde/\ + # ${TARGET_BINARY_INTERFACE:-m88kdgux}/usr/lib/libm.a + # + # , the compilation tools expand the environment variables.) + } else { + warn "$thislib not found in $thispth\n" if $verbose; + next; + } + warn "'-l$thislib' found at $fullname\n" if $verbose; + my($fullnamedir) = dirname($fullname); + push @ld_run_path, $fullnamedir unless $ld_run_path_seen{$fullnamedir}++; + $found++; + $found_lib++; + + # Now update library lists + + # what do we know about this library... + my $is_dyna = ($fullname !~ /\Q$Config_libext\E$/); + my $in_perl = ($libs =~ /\B-l\Q$ {thislib}\E\b/s); + + # Do not add it into the list if it is already linked in + # with the main perl executable. + # We have to special-case the NeXT, because math and ndbm + # are both in libsys_s + unless ($in_perl || + ($Config{'osname'} eq 'next' && + ($thislib eq 'm' || $thislib eq 'ndbm')) ){ + push(@extralibs, "-l$thislib"); + } + + # We might be able to load this archive file dynamically + if ( ($Config{'dlsrc'} =~ /dl_next/ && $Config{'osvers'} lt '4_0') + || ($Config{'dlsrc'} =~ /dl_dld/) ) + { + # We push -l$thislib instead of $fullname because + # it avoids hardwiring a fixed path into the .bs file. + # Mkbootstrap will automatically add dl_findfile() to + # the .bs file if it sees a name in the -l format. + # USE THIS, when dl_findfile() is fixed: + # push(@bsloadlibs, "-l$thislib"); + # OLD USE WAS while checking results against old_extliblist + push(@bsloadlibs, "$fullname"); + } else { + if ($is_dyna){ + # For SunOS4, do not add in this shared library if + # it is already linked in the main perl executable + push(@ldloadlibs, "-l$thislib") + unless ($in_perl and $^O eq 'sunos'); + } else { + push(@ldloadlibs, "-l$thislib"); + } + } + last; # found one here so don't bother looking further + } + warn "Note (probably harmless): " + ."No library found for -l$thislib\n" + unless $found_lib>0; + } + return ('','','','') unless $found; + ("@extralibs", "@bsloadlibs", "@ldloadlibs",join(":",@ld_run_path)); +} + +sub _win32_ext { + + require Text::ParseWords; + + my($self, $potential_libs, $verbose) = @_; + + # If user did not supply a list, we punt. + # (caller should probably use the list in $Config{libs}) + return ("", "", "", "") unless $potential_libs; + + my $cc = $Config{cc}; + my $VC = 1 if $cc =~ /^cl/i; + my $BC = 1 if $cc =~ /^bcc/i; + my $GC = 1 if $cc =~ /^gcc/i; + my $so = $Config{'so'}; + my $libs = $Config{'libs'}; + my $libpth = $Config{'libpth'}; + my $libext = $Config{'lib_ext'} || ".lib"; + + if ($libs and $potential_libs !~ /:nodefault/i) { + # If Config.pm defines a set of default libs, we always + # tack them on to the user-supplied list, unless the user + # specified :nodefault + + $potential_libs .= " " if $potential_libs; + $potential_libs .= $libs; + } + warn "Potential libraries are '$potential_libs':\n" if $verbose; + + # normalize to forward slashes + $libpth =~ s,\\,/,g; + $potential_libs =~ s,\\,/,g; + + # compute $extralibs from $potential_libs + + my @searchpath; # from "-L/path" in $potential_libs + my @libpath = Text::ParseWords::quotewords('\s+', 0, $libpth); + my @extralibs; + my $pwd = cwd(); # from Cwd.pm + my $lib = ''; + my $found = 0; + my $search = 1; + my($fullname, $thislib, $thispth); + + foreach (Text::ParseWords::quotewords('\s+', 0, $potential_libs)){ + + $thislib = $_; + + # see if entry is a flag + if (/^:\w+$/) { + $search = 0 if lc eq ':nosearch'; + $search = 1 if lc eq ':search'; + warn "Ignoring unknown flag '$thislib'\n" + if $verbose and !/^:(no)?(search|default)$/i; + next; + } + + # if searching is disabled, do compiler-specific translations + unless ($search) { + s/^-L/-libpath:/ if $VC; + s/^-l(.+)$/$1.lib/ unless $GC; + push(@extralibs, $_); + $found++; + next; + } + + # handle possible linker path arguments + if (s/^-L// and not -d) { + warn "$thislib ignored, directory does not exist\n" + if $verbose; + next; + } + elsif (-d) { + unless ($self->file_name_is_absolute($_)) { + warn "Warning: '$thislib' changed to '-L$pwd/$_'\n"; + $_ = $self->catdir($pwd,$_); + } + push(@searchpath, $_); + next; + } + + # handle possible library arguments + if (s/^-l// and $GC and !/^lib/i) { + $_ = "lib$_"; + } + $_ .= $libext if !/\Q$libext\E$/i; + + my $secondpass = 0; + LOOKAGAIN: + + # look for the file itself + if (-f) { + warn "'$thislib' found as '$_'\n" if $verbose; + $found++; + push(@extralibs, $_); + next; + } + + my $found_lib = 0; + foreach $thispth (@searchpath, @libpath){ + unless (-f ($fullname="$thispth\\$_")) { + warn "'$thislib' not found as '$fullname'\n" if $verbose; + next; + } + warn "'$thislib' found as '$fullname'\n" if $verbose; + $found++; + $found_lib++; + push(@extralibs, $fullname); + last; + } + + # do another pass with (or without) leading 'lib' if they used -l + if (!$found_lib and $thislib =~ /^-l/ and !$secondpass++) { + if ($GC) { + goto LOOKAGAIN if s/^lib//i; + } + elsif (!/^lib/i) { + $_ = "lib$_"; + goto LOOKAGAIN; + } + } + + # give up + warn "Note (probably harmless): " + ."No library found for '$thislib'\n" + unless $found_lib>0; + + } + + return ('','','','') unless $found; + + # make sure paths with spaces are properly quoted + @extralibs = map { (/\s/ && !/^".*"$/) ? qq["$_"] : $_ } @extralibs; + $lib = join(' ',@extralibs); + + # normalize back to backward slashes (to help braindead tools) + # XXX this may break equally braindead GNU tools that don't understand + # backslashes, either. Seems like one can't win here. Cursed be CP/M. + $lib =~ s,/,\\,g; + + warn "Result: $lib\n" if $verbose; + wantarray ? ($lib, '', $lib, '') : $lib; +} + + +sub _vms_ext { + my($self, $potential_libs,$verbose) = @_; + my(@crtls,$crtlstr); + my($dbgqual) = $self->{OPTIMIZE} || $Config{'optimize'} || + $self->{CCFLAS} || $Config{'ccflags'}; + @crtls = ( ($dbgqual =~ m-/Debug-i ? $Config{'dbgprefix'} : '') + . 'PerlShr/Share' ); + push(@crtls, grep { not /\(/ } split /\s+/, $Config{'libs'}); + push(@crtls, grep { not /\(/ } split /\s+/, $Config{'libc'}); + # In general, we pass through the basic libraries from %Config unchanged. + # The one exception is that if we're building in the Perl source tree, and + # a library spec could be resolved via a logical name, we go to some trouble + # to insure that the copy in the local tree is used, rather than one to + # which a system-wide logical may point. + if ($self->{PERL_SRC}) { + my($lib,$locspec,$type); + foreach $lib (@crtls) { + if (($locspec,$type) = $lib =~ m-^([\w$\-]+)(/\w+)?- and $locspec =~ /perl/i) { + if (lc $type eq '/share') { $locspec .= $Config{'exe_ext'}; } + elsif (lc $type eq '/library') { $locspec .= $Config{'lib_ext'}; } + else { $locspec .= $Config{'obj_ext'}; } + $locspec = $self->catfile($self->{PERL_SRC},$locspec); + $lib = "$locspec$type" if -e $locspec; + } + } + } + $crtlstr = @crtls ? join(' ',@crtls) : ''; + + unless ($potential_libs) { + warn "Result:\n\tEXTRALIBS: \n\tLDLOADLIBS: $crtlstr\n" if $verbose; + return ('', '', $crtlstr, ''); + } + + my(@dirs,@libs,$dir,$lib,%sh,%olb,%obj,$ldlib); + my $cwd = cwd(); + my($so,$lib_ext,$obj_ext) = @Config{'so','lib_ext','obj_ext'}; + # List of common Unix library names and there VMS equivalents + # (VMS equivalent of '' indicates that the library is automatially + # searched by the linker, and should be skipped here.) + my %libmap = ( 'm' => '', 'f77' => '', 'F77' => '', 'V77' => '', 'c' => '', + 'malloc' => '', 'crypt' => '', 'resolv' => '', 'c_s' => '', + 'socket' => '', 'X11' => 'DECW$XLIBSHR', + 'Xt' => 'DECW$XTSHR', 'Xm' => 'DECW$XMLIBSHR', + 'Xmu' => 'DECW$XMULIBSHR'); + if ($Config{'vms_cc_type'} ne 'decc') { $libmap{'curses'} = 'VAXCCURSE'; } + + warn "Potential libraries are '$potential_libs'\n" if $verbose; + + # First, sort out directories and library names in the input + foreach $lib (split ' ',$potential_libs) { + push(@dirs,$1), next if $lib =~ /^-L(.*)/; + push(@dirs,$lib), next if $lib =~ /[:>\]]$/; + push(@dirs,$lib), next if -d $lib; + push(@libs,$1), next if $lib =~ /^-l(.*)/; + push(@libs,$lib); + } + push(@dirs,split(' ',$Config{'libpth'})); + + # Now make sure we've got VMS-syntax absolute directory specs + # (We don't, however, check whether someone's hidden a relative + # path in a logical name.) + foreach $dir (@dirs) { + unless (-d $dir) { + warn "Skipping nonexistent Directory $dir\n" if $verbose > 1; + $dir = ''; + next; + } + warn "Resolving directory $dir\n" if $verbose; + if ($self->file_name_is_absolute($dir)) { $dir = $self->fixpath($dir,1); } + else { $dir = $self->catdir($cwd,$dir); } + } + @dirs = grep { length($_) } @dirs; + unshift(@dirs,''); # Check each $lib without additions first + + LIB: foreach $lib (@libs) { + if (exists $libmap{$lib}) { + next unless length $libmap{$lib}; + $lib = $libmap{$lib}; + } + + my(@variants,$variant,$name,$test,$cand); + my($ctype) = ''; + + # If we don't have a file type, consider it a possibly abbreviated name and + # check for common variants. We try these first to grab libraries before + # a like-named executable image (e.g. -lperl resolves to perlshr.exe + # before perl.exe). + if ($lib !~ /\.[^:>\]]*$/) { + push(@variants,"${lib}shr","${lib}rtl","${lib}lib"); + push(@variants,"lib$lib") if $lib !~ /[:>\]]/; + } + push(@variants,$lib); + warn "Looking for $lib\n" if $verbose; + foreach $variant (@variants) { + foreach $dir (@dirs) { + my($type); + + $name = "$dir$variant"; + warn "\tChecking $name\n" if $verbose > 2; + if (-f ($test = VMS::Filespec::rmsexpand($name))) { + # It's got its own suffix, so we'll have to figure out the type + if ($test =~ /(?:$so|exe)$/i) { $type = 'sh'; } + elsif ($test =~ /(?:$lib_ext|olb)$/i) { $type = 'olb'; } + elsif ($test =~ /(?:$obj_ext|obj)$/i) { + warn "Note (probably harmless): " + ."Plain object file $test found in library list\n"; + $type = 'obj'; + } + else { + warn "Note (probably harmless): " + ."Unknown library type for $test; assuming shared\n"; + $type = 'sh'; + } + } + elsif (-f ($test = VMS::Filespec::rmsexpand($name,$so)) or + -f ($test = VMS::Filespec::rmsexpand($name,'.exe'))) { + $type = 'sh'; + $name = $test unless $test =~ /exe;?\d*$/i; + } + elsif (not length($ctype) and # If we've got a lib already, don't bother + ( -f ($test = VMS::Filespec::rmsexpand($name,$lib_ext)) or + -f ($test = VMS::Filespec::rmsexpand($name,'.olb')))) { + $type = 'olb'; + $name = $test unless $test =~ /olb;?\d*$/i; + } + elsif (not length($ctype) and # If we've got a lib already, don't bother + ( -f ($test = VMS::Filespec::rmsexpand($name,$obj_ext)) or + -f ($test = VMS::Filespec::rmsexpand($name,'.obj')))) { + warn "Note (probably harmless): " + ."Plain object file $test found in library list\n"; + $type = 'obj'; + $name = $test unless $test =~ /obj;?\d*$/i; + } + if (defined $type) { + $ctype = $type; $cand = $name; + last if $ctype eq 'sh'; + } + } + if ($ctype) { + eval '$' . $ctype . "{'$cand'}++"; + die "Error recording library: $@" if $@; + warn "\tFound as $cand (really $test), type $ctype\n" if $verbose > 1; + next LIB; + } + } + warn "Note (probably harmless): " + ."No library found for $lib\n"; + } + + @libs = sort keys %obj; + # This has to precede any other CRTLs, so just make it first + if ($olb{VAXCCURSE}) { + push(@libs,"$olb{VAXCCURSE}/Library"); + delete $olb{VAXCCURSE}; + } + push(@libs, map { "$_/Library" } sort keys %olb); + push(@libs, map { "$_/Share" } sort keys %sh); + $lib = join(' ',@libs); + + $ldlib = $crtlstr ? "$lib $crtlstr" : $lib; + warn "Result:\n\tEXTRALIBS: $lib\n\tLDLOADLIBS: $ldlib\n" if $verbose; + wantarray ? ($lib, '', $ldlib, '') : $lib; +} + +1; + +__END__ + +=head1 NAME + +ExtUtils::Liblist - determine libraries to use and how to use them + +=head1 SYNOPSIS + +C<require ExtUtils::Liblist;> + +C<ExtUtils::Liblist::ext($self, $potential_libs, $verbose);> + +=head1 DESCRIPTION + +This utility takes a list of libraries in the form C<-llib1 -llib2 +-llib3> and prints out lines suitable for inclusion in an extension +Makefile. Extra library paths may be included with the form +C<-L/another/path> this will affect the searches for all subsequent +libraries. + +It returns an array of four scalar values: EXTRALIBS, BSLOADLIBS, +LDLOADLIBS, and LD_RUN_PATH. Some of these don't mean anything +on VMS and Win32. See the details about those platform specifics +below. + +Dependent libraries can be linked in one of three ways: + +=over 2 + +=item * For static extensions + +by the ld command when the perl binary is linked with the extension +library. See EXTRALIBS below. + +=item * For dynamic extensions + +by the ld command when the shared object is built/linked. See +LDLOADLIBS below. + +=item * For dynamic extensions + +by the DynaLoader when the shared object is loaded. See BSLOADLIBS +below. + +=back + +=head2 EXTRALIBS + +List of libraries that need to be linked with when linking a perl +binary which includes this extension Only those libraries that +actually exist are included. These are written to a file and used +when linking perl. + +=head2 LDLOADLIBS and LD_RUN_PATH + +List of those libraries which can or must be linked into the shared +library when created using ld. These may be static or dynamic +libraries. LD_RUN_PATH is a colon separated list of the directories +in LDLOADLIBS. It is passed as an environment variable to the process +that links the shared library. + +=head2 BSLOADLIBS + +List of those libraries that are needed but can be linked in +dynamically at run time on this platform. SunOS/Solaris does not need +this because ld records the information (from LDLOADLIBS) into the +object file. This list is used to create a .bs (bootstrap) file. + +=head1 PORTABILITY + +This module deals with a lot of system dependencies and has quite a +few architecture specific B<if>s in the code. + +=head2 VMS implementation + +The version of ext() which is executed under VMS differs from the +Unix-OS/2 version in several respects: + +=over 2 + +=item * + +Input library and path specifications are accepted with or without the +C<-l> and C<-L> prefices used by Unix linkers. If neither prefix is +present, a token is considered a directory to search if it is in fact +a directory, and a library to search for otherwise. Authors who wish +their extensions to be portable to Unix or OS/2 should use the Unix +prefixes, since the Unix-OS/2 version of ext() requires them. + +=item * + +Wherever possible, shareable images are preferred to object libraries, +and object libraries to plain object files. In accordance with VMS +naming conventions, ext() looks for files named I<lib>shr and I<lib>rtl; +it also looks for I<lib>lib and libI<lib> to accomodate Unix conventions +used in some ported software. + +=item * + +For each library that is found, an appropriate directive for a linker options +file is generated. The return values are space-separated strings of +these directives, rather than elements used on the linker command line. + +=item * + +LDLOADLIBS contains both the libraries found based on C<$potential_libs> and +the CRTLs, if any, specified in Config.pm. EXTRALIBS contains just those +libraries found based on C<$potential_libs>. BSLOADLIBS and LD_RUN_PATH +are always empty. + +=back + +In addition, an attempt is made to recognize several common Unix library +names, and filter them out or convert them to their VMS equivalents, as +appropriate. + +In general, the VMS version of ext() should properly handle input from +extensions originally designed for a Unix or VMS environment. If you +encounter problems, or discover cases where the search could be improved, +please let us know. + +=head2 Win32 implementation + +The version of ext() which is executed under Win32 differs from the +Unix-OS/2 version in several respects: + +=over 2 + +=item * + +If C<$potential_libs> is empty, the return value will be empty. +Otherwise, the libraries specified by C<$Config{libs}> (see Config.pm) +will be appended to the list of C<$potential_libs>. The libraries +will be searched for in the directories specified in C<$potential_libs> +as well as in C<$Config{libpth}>. For each library that is found, a +space-separated list of fully qualified library pathnames is generated. + +=item * + +Input library and path specifications are accepted with or without the +C<-l> and C<-L> prefices used by Unix linkers. + +An entry of the form C<-La:\foo> specifies the C<a:\foo> directory to look +for the libraries that follow. + +An entry of the form C<-lfoo> specifies the library C<foo>, which may be +spelled differently depending on what kind of compiler you are using. If +you are using GCC, it gets translated to C<libfoo.a>, but for other win32 +compilers, it becomes C<foo.lib>. If no files are found by those translated +names, one more attempt is made to find them using either C<foo.a> or +C<libfoo.lib>, depending on whether GCC or some other win32 compiler is +being used, respectively. + +If neither the C<-L> or C<-l> prefix is present in an entry, the entry is +considered a directory to search if it is in fact a directory, and a +library to search for otherwise. The C<$Config{lib_ext}> suffix will +be appended to any entries that are not directories and don't already have +the suffix. + +Note that the C<-L> and <-l> prefixes are B<not required>, but authors +who wish their extensions to be portable to Unix or OS/2 should use the +prefixes, since the Unix-OS/2 version of ext() requires them. + +=item * + +Entries cannot be plain object files, as many Win32 compilers will +not handle object files in the place of libraries. + +=item * + +Entries in C<$potential_libs> beginning with a colon and followed by +alphanumeric characters are treated as flags. Unknown flags will be ignored. + +An entry that matches C</:nodefault/i> disables the appending of default +libraries found in C<$Config{libs}> (this should be only needed very rarely). + +An entry that matches C</:nosearch/i> disables all searching for +the libraries specified after it. Translation of C<-Lfoo> and +C<-lfoo> still happens as appropriate (depending on compiler being used, +as reflected by C<$Config{cc}>), but the entries are not verified to be +valid files or directories. + +An entry that matches C</:search/i> reenables searching for +the libraries specified after it. You can put it at the end to +enable searching for default libraries specified by C<$Config{libs}>. + +=item * + +The libraries specified may be a mixture of static libraries and +import libraries (to link with DLLs). Since both kinds are used +pretty transparently on the win32 platform, we do not attempt to +distinguish between them. + +=item * + +LDLOADLIBS and EXTRALIBS are always identical under Win32, and BSLOADLIBS +and LD_RUN_PATH are always empty (this may change in future). + +=item * + +You must make sure that any paths and path components are properly +surrounded with double-quotes if they contain spaces. For example, +C<$potential_libs> could be (literally): + + "-Lc:\Program Files\vc\lib" msvcrt.lib "la test\foo bar.lib" + +Note how the first and last entries are protected by quotes in order +to protect the spaces. + +=item * + +Since this module is most often used only indirectly from extension +C<Makefile.PL> files, here is an example C<Makefile.PL> entry to add +a library to the build process for an extension: + + LIBS => ['-lgl'] + +When using GCC, that entry specifies that MakeMaker should first look +for C<libgl.a> (followed by C<gl.a>) in all the locations specified by +C<$Config{libpth}>. + +When using a compiler other than GCC, the above entry will search for +C<gl.lib> (followed by C<libgl.lib>). + +If the library happens to be in a location not in C<$Config{libpth}>, +you need: + + LIBS => ['-Lc:\gllibs -lgl'] + +Here is a less often used example: + + LIBS => ['-lgl', ':nosearch -Ld:\mesalibs -lmesa -luser32'] + +This specifies a search for library C<gl> as before. If that search +fails to find the library, it looks at the next item in the list. The +C<:nosearch> flag will prevent searching for the libraries that follow, +so it simply returns the value as C<-Ld:\mesalibs -lmesa -luser32>, +since GCC can use that value as is with its linker. + +When using the Visual C compiler, the second item is returned as +C<-libpath:d:\mesalibs mesa.lib user32.lib>. + +When using the Borland compiler, the second item is returned as +C<-Ld:\mesalibs mesa.lib user32.lib>, and MakeMaker takes care of +moving the C<-Ld:\mesalibs> to the correct place in the linker +command line. + +=back + + +=head1 SEE ALSO + +L<ExtUtils::MakeMaker> + +=cut + |
