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
+our $VERSION = substr q$Revision: 1.27 $, 10;
+
use Config;
-use Cwd;
-# --- Determine libraries to use and how to use them ---
+use Cwd 'cwd';
+use File::Basename;
sub ext {
- my($potential_libs, $Verbose) = @_;
- return ("", "", "") unless $potential_libs;
- print STDOUT "Potential libraries are '$potential_libs':\n" if $Verbose;
+ if ($^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 .= $Config{perllibs};
+ }
+ return ("", "", "", "", ($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 <distribution>/ext/util
my(@searchpath); # from "-L/path" entries in $potential_libs
my(@libpath) = split " ", $Config{'libpth'};
- my(@ldloadlibs, @bsloadlibs, @extralibs);
+ my(@ldloadlibs, @bsloadlibs, @extralibs, @ld_run_path, %ld_run_path_seen);
+ my(@libs, %libs_seen);
my($fullname, $thislib, $thispth, @fullname);
- my($pwd) = fastcwd(); # from Cwd.pm
+ my($pwd) = cwd(); # from Cwd.pm
my($found) = 0;
foreach $thislib (split ' ', $potential_libs){
if ($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 $verbose;
next;
}
- if ($thislib !~ m|^/|) {
- print STDOUT "Warning: $ptype$thislib changed to $ptype$pwd/$thislib\n";
- $thislib = "$pwd/$thislib";
+ unless ($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$thislib");
# Handle possible library arguments.
unless ($thislib =~ s/^-l//){
- print STDOUT "Unrecognized argument in LIBS ignored: '$thislib'\n";
+ warn "Unrecognized argument in LIBS ignored: '$thislib'\n";
next;
}
# 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 = 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
$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.a")
+ } 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$thislib.a")){
- } elsif (-f ($fullname="$thispth/Slib$thislib.a")){
+ } 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:/s) {
+ # 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/\
+ # ${TARGET_BINARY_INTERFACE:-m88kdgux}/usr/lib/libm.a
+ #
+ # , the compilation tools expand the environment variables.)
} else {
- print STDOUT "$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 !~ /\.a$/);
- my $in_perl = ($libs =~ /\B-l${thislib}\b/s);
+ 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 ($in_perl ||
- ($Config{'osname'} 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 $fullname because
# it avoids hardwiring a fixed path into the .bs file.
# Mkbootstrap will automatically add dl_findfile() to
# For SunOS4, do not add in this shared library if
# it is already linked in the main perl executable
push(@ldloadlibs, "-l$thislib")
- unless ($in_perl and $Config{'osname'} eq 'sunos');
+ unless ($in_perl and $^O eq 'sunos');
} else {
push(@ldloadlibs, "-l$thislib");
}
}
last; # found one here so don't bother looking further
}
- print STDOUT "Warning (non-fatal): No library found for -l$thislib\n"
+ warn "Note (probably harmless): "
+ ."No library found for -l$thislib\n"
unless $found_lib>0;
}
- return ('','','') unless $found;
- ("@extralibs", "@bsloadlibs", "@ldloadlibs");
+ return ('','','','', ($give_libs ? \@libs : ())) unless $found;
+ ("@extralibs", "@bsloadlibs", "@ldloadlibs",join(":",@ld_run_path), ($give_libs ? \@libs : ()));
}
-sub lsdir { #yes, duplicate code seems less hassle than having an
- #extra file with only lsdir
- my($dir, $regex) = @_;
- local(*DIR, @ls);
- opendir(DIR, $dir || ".") or return ();
- @ls = readdir(DIR);
- closedir(DIR);
- @ls = grep(/$regex/, @ls) if $regex;
- @ls;
+sub _win32_ext {
+
+ require Text::ParseWords;
+
+ my($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 $found_lib>0;
+
+ }
+
+ return ('','','','', ($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 : ())) : $lib;
}
1;
+
+__END__
+
+=head1 NAME
+
+ExtUtils::Liblist - determine libraries to use and how to use them
+
+=head1 SYNOPSIS
+
+C<require ExtUtils::Liblist;>
+
+C<ExtUtils::Liblist::ext($self, $potential_libs, $verbose, $need_names);>
+
+=head1 DESCRIPTION
+
+This utility takes a list of libraries in the form C<-llib1 -llib2
+-llib3> and returns lines suitable for inclusion in an extension
+Makefile. Extra library paths may be included with the form
+C<-L/another/path> this will affect the searches for all subsequent
+libraries.
+
+It returns an array of four or five scalar values: EXTRALIBS,
+BSLOADLIBS, LDLOADLIBS, LD_RUN_PATH, and, optionally, a reference to
+the array of the filenames of actual libraries. Some of these don't
+mean anything unless on Unix. See the details about those platform
+specifics below. The list of the filenames is returned only if
+$need_names argument is true.
+
+Dependent libraries can be linked in one of three ways:
+
+=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 C<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> 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 I<lib>shr and I<lib>rtl;
+it also looks for I<lib>lib and libI<lib> 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<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<$Config{lib_ext}> suffix will
+be appended to any entries that are not directories and don't already have
+the suffix.
+
+Note that the C<-L> and C<-l> prefixes are B<not required>, but authors
+who wish their extensions to be portable to Unix or OS/2 should use the
+prefixes, since the Unix-OS/2 version of ext() requires them.
+
+=item *
+
+Entries cannot be plain object files, as many Win32 compilers will
+not handle object files in the place of libraries.
+
+=item *
+
+Entries in C<$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<$Config{perllibs}> (this should be only needed very rarely).
+
+An entry that matches C</:nosearch/i> disables all searching for
+the libraries specified after it. Translation of C<-Lfoo> and
+C<-lfoo> still happens as appropriate (depending on compiler being used,
+as reflected by C<$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<$Config{perllibs}>.
+
+=item *
+
+The libraries specified may be a mixture of static libraries and
+import libraries (to link with DLLs). Since both kinds are used
+pretty transparently on the Win32 platform, we do not attempt to
+distinguish between them.
+
+=item *
+
+LDLOADLIBS and EXTRALIBS are always identical under Win32, and BSLOADLIBS
+and LD_RUN_PATH are always empty (this may change in future).
+
+=item *
+
+You must make sure that any paths and path components are properly
+surrounded with double-quotes if they contain spaces. For example,
+C<$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<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
+
projects / p5sagit/p5-mst-13.2.git / blobdiff