X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FExtUtils%2FLiblist.pm;h=09421e331fd6b2d6cc70acca3b26ae867fd85f75;hb=983ffd37e39751798fdd14853511af238c5fe291;hp=77aa831bc7679250a9a22c7176ab5123fbf0eacf;hpb=f1387719c66d49522b38f85cae0c68334115d46b;p=p5sagit%2Fp5-mst-13.2.git diff --git a/lib/ExtUtils/Liblist.pm b/lib/ExtUtils/Liblist.pm index 77aa831..09421e3 100644 --- a/lib/ExtUtils/Liblist.pm +++ b/lib/ExtUtils/Liblist.pm @@ -1,38 +1,66 @@ package ExtUtils::Liblist; +@ISA = qw(ExtUtils::Liblist::Kid File::Spec); + +sub lsdir { + shift; + my $rex = qr/$_[1]/; + opendir my $dir, $_[0]; + grep /$rex/, readdir $dir; +} + +sub file_name_is_absolute { + require File::Spec; + shift; + 'File::Spec'->file_name_is_absolute(@_); +} + + +package ExtUtils::Liblist::Kid; + +# This kid package is to be used by MakeMaker. It will not work if +# $self is not a Makemaker. + +use 5.006_001; # Broken out of MakeMaker from version 4.11 -$ExtUtils::Liblist::VERSION = substr q$Revision: 1.19 $, 10; +our $VERSION = substr q$Revision: 1.27 $, 10; use Config; use Cwd 'cwd'; use File::Basename; -my $Config_libext = $Config{lib_ext} || ".a"; - sub ext { - my($self,$potential_libs, $Verbose) = @_; - if ($^O =~ 'os2' and $Config{libs}) { + if ($^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, $give_libs) = @_; + if ($^O =~ 'os2' and $Config{perllibs}) { # 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}; + $potential_libs .= $Config{perllibs}; } - return ("", "", "", "") unless $potential_libs; - print STDOUT "Potential libraries are '$potential_libs':\n" if $Verbose; + return ("", "", "", "", ($give_libs ? [] : ())) unless $potential_libs; + warn "Potential libraries are '$potential_libs':\n" if $verbose; my($so) = $Config{'so'}; - my($libs) = $Config{'libs'}; + my($libs) = $Config{'perllibs'}; + 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 - # its home is in /ext/util my(@searchpath); # from "-L/path" entries in $potential_libs my(@libpath) = split " ", $Config{'libpth'}; my(@ldloadlibs, @bsloadlibs, @extralibs, @ld_run_path, %ld_run_path_seen); + my(@libs, %libs_seen); my($fullname, $thislib, $thispth, @fullname); my($pwd) = cwd(); # from Cwd.pm my($found) = 0; @@ -43,12 +71,12 @@ sub ext { if ($thislib =~ s/^(-[LR])//){ # save path flag type my($ptype) = $1; unless (-d $thislib){ - print STDOUT "$ptype$thislib ignored, directory does not exist\n" - if $Verbose; + warn "$ptype$thislib ignored, directory does not exist\n" + if $verbose; next; } unless ($self->file_name_is_absolute($thislib)) { - print STDOUT "Warning: $ptype$thislib changed to $ptype$pwd/$thislib\n"; + warn "Warning: $ptype$thislib changed to $ptype$pwd/$thislib\n"; $thislib = $self->catdir($pwd,$thislib); } push(@searchpath, $thislib); @@ -59,7 +87,7 @@ sub ext { # Handle possible library arguments. unless ($thislib =~ s/^-l//){ - print STDOUT "Unrecognized argument in LIBS ignored: '$thislib'\n"; + warn "Unrecognized argument in LIBS ignored: '$thislib'\n"; next; } @@ -72,7 +100,8 @@ sub ext { # 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,"^lib$thislib\.$so\.[0-9]+")){ + 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 @@ -102,13 +131,14 @@ sub ext { } 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") + && (! $Config{'archname'} =~ /RM\d\d\d-svr4/) && ($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:/) { + && readlink($fullname) =~ /^elink:/s) { # Some of DG's libraries look like misconnected symbolic # links, but development tools can follow them. (They # look like this: @@ -118,32 +148,36 @@ sub ext { # # , the compilation tools expand the environment variables.) } else { - print STDOUT "$thislib not found in $thispth\n" if $Verbose; + warn "$thislib not found in $thispth\n" if $verbose; next; } - print STDOUT "'-l$thislib' found at $fullname\n" if $Verbose; + warn "'-l$thislib' found at $fullname\n" if $verbose; my($fullnamedir) = dirname($fullname); push @ld_run_path, $fullnamedir unless $ld_run_path_seen{$fullnamedir}++; + push @libs, $fullname unless $libs_seen{$fullname}++; $found++; $found_lib++; # Now update library lists # what do we know about this library... - my $is_dyna = ($fullname !~ /\Q$Config_libext\E$/); + my $is_dyna = ($fullname !~ /\Q$Config_libext\E\z/); 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 all the math - # is also in libsys_s + # We have to special-case the NeXT, because math and ndbm + # are both in libsys_s unless ($in_perl || - ($^O eq 'next' && $thislib eq 'm') ){ + ($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 ( $Config{'dlsrc'} =~ /dl_next|dl_dld/){ + if ( ($Config{'dlsrc'} =~ /dl_next/ && $Config{'osvers'} lt '4_0') + || ($Config{'dlsrc'} =~ /dl_dld/) ) + { # We push -l$thislib instead of $fullname because # it avoids hardwiring a fixed path into the .bs file. # Mkbootstrap will automatically add dl_findfile() to @@ -164,11 +198,329 @@ sub ext { } last; # found one here so don't bother looking further } - print STDOUT "Warning (will try anyway): No library found for -l$thislib\n" + warn "Note (probably harmless): " + ."No library found for -l$thislib\n" + unless $found_lib>0; + } + return ('','','','', ($give_libs ? \@libs : ())) unless $found; + ("@extralibs", "@bsloadlibs", "@ldloadlibs",join(":",@ld_run_path), ($give_libs ? \@libs : ())); +} + +sub _win32_ext { + + require Text::ParseWords; + + my($self, $potential_libs, $verbose, $give_libs) = @_; + + # If user did not supply a list, we punt. + # (caller should probably use the list in $Config{libs}) + return ("", "", "", "", ($give_libs ? [] : ())) 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{'perllibs'}; + my $libpth = $Config{'libpth'}; + my $libext = $Config{'lib_ext'} || ".lib"; + my(@libs, %libs_seen); + + if ($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, $thispth); + + # add "$Config{installarchlib}/CORE" to default search path + push @libpath, "$Config{installarchlib}/CORE"; + + if ($VC and exists $ENV{LIB} and $ENV{LIB}) { + push @libpath, split /;/, $ENV{LIB}; + } + + 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 ($search) { + s/^-l(.+)$/$1.lib/ unless $GC; + s/^-L/-libpath:/ if $VC; + 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); + push @libs, $fullname unless $libs_seen{$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 $found; - ("@extralibs", "@bsloadlibs", "@ldloadlibs",join(":",@ld_run_path)); + + return ('','','','', ($give_libs ? \@libs : ())) unless $found; + + # make sure paths with spaces are properly quoted + @extralibs = map { (/\s/ && !/^".*"$/) ? qq["$_"] : $_ } @extralibs; + @libs = map { (/\s/ && !/^".*"$/) ? qq["$_"] : $_ } @libs; + $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, '', $lib, '', ($give_libs ? \@libs : ())) : $lib; +} + + +sub _vms_ext { + my($self, $potential_libs,$verbose,$give_libs) = @_; + my(@crtls,$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{'perllibs'}); + 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 ('', '', $crtlstr, '', ($give_libs ? [] : ())); + } + + my(@dirs,@libs,$dir,$lib,%found,@fndlibs,$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(@flibs, %libs_seen); + 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) { $type = 'SHR'; } + elsif ($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"; + $type = 'SHR'; + } + } + elsif (-f ($test = VMS::Filespec::rmsexpand($name,$so)) or + -f ($test = VMS::Filespec::rmsexpand($name,'.exe'))) { + $type = 'SHR'; + $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 $ctype eq 'SHR'; + } + } + if ($ctype) { + # This has to precede any other CRTLs, so just make it first + if ($cand eq 'VAXCCURSE') { unshift @{$found{$ctype}}, $cand; } + else { push @{$found{$ctype}}, $cand; } + warn "\tFound as $cand (really $test), type $ctype\n" if $verbose > 1; + push @flibs, $name unless $libs_seen{$fullname}++; + next LIB; + } + } + warn "Note (probably harmless): " + ."No library found for $lib\n"; + } + + push @fndlibs, @{$found{OBJ}} if exists $found{OBJ}; + push @fndlibs, map { "$_/Library" } @{$found{OLB}} if exists $found{OLB}; + push @fndlibs, map { "$_/Share" } @{$found{SHR}} if exists $found{SHR}; + $lib = join(' ',@fndlibs); + + $ldlib = $crtlstr ? "$lib $crtlstr" : $lib; + warn "Result:\n\tEXTRALIBS: $lib\n\tLDLOADLIBS: $ldlib\n" if $verbose; + wantarray ? ($lib, '', $ldlib, '', ($give_libs ? \@flibs : ())) : $lib; } 1; @@ -183,18 +535,22 @@ ExtUtils::Liblist - determine libraries to use and how to use them C -C +C =head1 DESCRIPTION This utility takes a list of libraries in the form C<-llib1 -llib2 --llib3> and prints out lines suitable for inclusion in an extension +-llib3> and returns lines suitable for inclusion in an extension Makefile. Extra library paths may be included with the form C<-L/another/path> this will affect the searches for all subsequent libraries. -It returns an array of four scalar values: EXTRALIBS, BSLOADLIBS, -LDLOADLIBS, and LD_RUN_PATH. +It returns an array of four or five scalar values: EXTRALIBS, +BSLOADLIBS, LDLOADLIBS, LD_RUN_PATH, and, optionally, a reference to +the array of the filenames of actual libraries. Some of these don't +mean anything unless on Unix. See the details about those platform +specifics below. The list of the filenames is returned only if +$need_names argument is true. Dependent libraries can be linked in one of three ways: @@ -220,7 +576,7 @@ below. =head2 EXTRALIBS List of libraries that need to be linked with when linking a perl -binary which includes this extension Only those libraries that +binary which includes this extension. Only those libraries that actually exist are included. These are written to a file and used when linking perl. @@ -242,7 +598,185 @@ 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 Bs in the code. +few architecture specific Cs 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> prefixes 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 Ishr and Irtl; +it also looks for Ilib and libI to accommodate 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{perllibs}> (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>, +C<$Config{libpth}>, and in C<$Config{installarchlib}/CORE>. +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> prefixes used by Unix linkers. + +An entry of the form C<-La:\foo> specifies the C directory to look +for the libraries that follow. + +An entry of the form C<-lfoo> specifies the library C, which may be +spelled differently depending on what kind of compiler you are using. If +you are using GCC, it gets translated to C, but for other win32 +compilers, it becomes C. If no files are found by those translated +names, one more attempt is made to find them using either C or +C, 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<$Config{lib_ext}> suffix will +be appended to any entries that are not directories and don't already have +the suffix. + +Note that the C<-L> and C<-l> prefixes are B, but authors +who wish their extensions to be portable to Unix or OS/2 should use the +prefixes, since the Unix-OS/2 version of ext() requires them. + +=item * + +Entries cannot be plain object files, as many Win32 compilers will +not handle object files in the place of libraries. + +=item * + +Entries in C<$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 disables the appending of default +libraries found in C<$Config{perllibs}> (this should be only needed very rarely). + +An entry that matches C disables all searching for +the libraries specified after it. Translation of C<-Lfoo> and +C<-lfoo> still happens as appropriate (depending on compiler being used, +as reflected by C<$Config{cc}>), but the entries are not verified to be +valid files or directories. + +An entry that matches C reenables searching for +the libraries specified after it. You can put it at the end to +enable searching for default libraries specified by C<$Config{perllibs}>. + +=item * + +The libraries specified may be a mixture of static libraries and +import libraries (to link with DLLs). Since both kinds are used +pretty transparently on the Win32 platform, we do not attempt to +distinguish between them. + +=item * + +LDLOADLIBS and EXTRALIBS are always identical under Win32, and BSLOADLIBS +and LD_RUN_PATH are always empty (this may change in future). + +=item * + +You must make sure that any paths and path components are properly +surrounded with double-quotes if they contain spaces. For example, +C<$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 files, here is an example C 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 (followed by C) in all the locations specified by +C<$Config{libpth}>. + +When using a compiler other than GCC, the above entry will search for +C (followed by C). + +If the library happens to be in a location not in C<$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 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 @@ -250,5 +784,3 @@ L =cut - -