source: trunk/essentials/dev-lang/perl/lib/ExtUtils/Mkbootstrap.pm

package ExtUtils::Mkbootstrap;

$VERSION = 1.15;

use Config;
use Exporter;
@ISA=('Exporter');
@EXPORT='&Mkbootstrap';

sub Mkbootstrap {
    my($baseext, @bsloadlibs)=@_;
    @bsloadlibs = grep($_, @bsloadlibs); # strip empty libs

    print STDOUT "      bsloadlibs=@bsloadlibs\n" if $Verbose;

    # We need DynaLoader here because we and/or the *_BS file may
    # call dl_findfile(). We don't say `use' here because when
    # first building perl extensions the DynaLoader will not have
    # been built when MakeMaker gets first used.
    require DynaLoader;

    rename "$baseext.bs", "$baseext.bso"
      if -s "$baseext.bs";

    if (-f "${baseext}_BS"){
        $_ = "${baseext}_BS";
        package DynaLoader; # execute code as if in DynaLoader
        local($osname, $dlsrc) = (); # avoid warnings
        ($osname, $dlsrc) = @Config::Config{qw(osname dlsrc)};
        $bscode = "";
        unshift @INC, ".";
        require $_;
        shift @INC;
    }

    if ($Config{'dlsrc'} =~ /^dl_dld/){
        package DynaLoader;
        push(@dl_resolve_using, dl_findfile('-lc'));
    }

    my(@all) = (@bsloadlibs, @DynaLoader::dl_resolve_using);
    my($method) = '';
    if (@all){
        open BS, ">$baseext.bs"
                or die "Unable to open $baseext.bs: $!";
        print STDOUT "Writing $baseext.bs\n";
        print STDOUT "  containing: @all" if $Verbose;
        print BS "# $baseext DynaLoader bootstrap file for $^O architecture.\n";
        print BS "# Do not edit this file, changes will be lost.\n";
        print BS "# This file was automatically generated by the\n";
        print BS "# Mkbootstrap routine in ExtUtils::Mkbootstrap (v$VERSION).\n";
        print BS "\@DynaLoader::dl_resolve_using = ";
        # If @all contains names in the form -lxxx or -Lxxx then it's asking for
        # runtime library location so we automatically add a call to dl_findfile()
        if (" @all" =~ m/ -[lLR]/){
            print BS "  dl_findfile(qw(\n  @all\n  ));\n";
        }else{
            print BS "  qw(@all);\n";
        }
        # write extra code if *_BS says so
        print BS $DynaLoader::bscode if $DynaLoader::bscode;
        print BS "\n1;\n";
        close BS;
    }
}

1;

__END__

=head1 NAME

ExtUtils::Mkbootstrap - make a bootstrap file for use by DynaLoader

=head1 SYNOPSIS

C<Mkbootstrap>

=head1 DESCRIPTION

Mkbootstrap typically gets called from an extension Makefile.

There is no C<*.bs> file supplied with the extension. Instead, there may
be a C<*_BS> file which has code for the special cases, like posix for
berkeley db on the NeXT.

This file will get parsed, and produce a maybe empty
C<@DynaLoader::dl_resolve_using> array for the current architecture.
That will be extended by $BSLOADLIBS, which was computed by
ExtUtils::Liblist::ext(). If this array still is empty, we do nothing,
else we write a .bs file with an C<@DynaLoader::dl_resolve_using>
array.

The C<*_BS> file can put some code into the generated C<*.bs> file by
placing it in C<$bscode>. This is a handy 'escape' mechanism that may
prove useful in complex situations.

If @DynaLoader::dl_resolve_using contains C<-L*> or C<-l*> entries then
Mkbootstrap will automatically add a dl_findfile() call to the
generated C<*.bs> file.

=cut