# Generated from XSLoader.pm.PL (resolved %Config::Config value)
# This file is unique for every OS

package XSLoader;

$VERSION = "0.24";

#use strict;

package DynaLoader;

# No prizes for guessing why we don't say 'bootstrap DynaLoader;' here.
# NOTE: All dl_*.xs (including dl_none.xs) define a dl_error() XSUB
boot_DynaLoader('DynaLoader') if defined(&boot_DynaLoader) &&
package XSLoader;

sub load {
    package DynaLoader;

    my ($caller, $modlibname) = caller();
    my $module = $caller;

    if (@_) {
        $module = $_[0];
    } else {
        $_[0] = $module;

    # work with static linking too
    my $boots = "$module\::bootstrap";
    goto &$boots if defined &$boots;

    goto \&XSLoader::bootstrap_inherit unless $module and defined &dl_load_file;

    my @modparts = split(/::/,$module);
    my $modfname = $modparts[-1];

    my $modpname = join('/',@modparts);
    my $c = () = split(/::/,$caller,-1);
    $modlibname =~ s,[\\/][^\\/]+$,, while $c--;    # Q&D basename
    # Does this look like a relative path?
    if ($modlibname !~ m{^/}) {
        # Someone may have a #line directive that changes the file name, or
        # may be calling XSLoader::load from inside a string eval.  We cer-
        # tainly do not want to go loading some code that is not in @INC,
        # as it could be untrusted.
        # We could just fall back to DynaLoader here, but then the rest of
        # this function would go untested in the perl core, since all @INC
        # paths are relative during testing.  That would be a time bomb
        # waiting to happen, since bugs could be introduced into the code.
        # So look through @INC to see if $modlibname is in it.  A rela-
        # tive $modlibname is not a common occurrence, so this block is
        # not hot code.
        FOUND: {
            for (@INC) {
                if ($_ eq $modlibname) {
                    last FOUND;
            # Not found.  Fall back to DynaLoader.
            goto \&XSLoader::bootstrap_inherit;
    my $file = "$modlibname/auto/$modpname/$modfname.bundle";

#   print STDERR "XSLoader::load for $module ($file)\n" if $dl_debug;

    my $bs = $file;
    $bs =~ s/(\.\w+)?(;\d*)?$/\.bs/; # look for .bs 'beside' the library

    if (-s $bs) { # only read file if it's not empty
#       print STDERR "BS: $bs ($^O, $dlsrc)\n" if $dl_debug;
        eval { do $bs; };
        warn "$bs: $@\n" if $@;
	goto \&XSLoader::bootstrap_inherit;

    goto \&XSLoader::bootstrap_inherit if not -f $file;

    my $bootname = "boot_$module";
    $bootname =~ s/\W/_/g;
    @DynaLoader::dl_require_symbols = ($bootname);

    my $boot_symbol_ref;

    if ($boot_symbol_ref = dl_find_symbol( 0, $bootname )) {
        goto boot; #extension library has already been loaded, e.g. darwin
    # Many dynamic extension loading problems will appear to come from
    # this section of code: XYZ failed at line 123 of DynaLoader.pm.
    # Often these errors are actually occurring in the initialisation
    # C code of the extension XS file. Perl reports the error as being
    # in this perl code simply because this was the last perl code
    # it executed.

    my $libref = dl_load_file($file, 0) or do { 
        require Carp;
        Carp::croak("Can't load '$file' for module $module: " . dl_error());
    push(@DynaLoader::dl_librefs,$libref);  # record loaded object

    $boot_symbol_ref = dl_find_symbol($libref, $bootname) or do {
        require Carp;
        Carp::croak("Can't find '$bootname' symbol in $file\n");

    push(@DynaLoader::dl_modules, $module); # record loaded module

    my $xs = dl_install_xsub($boots, $boot_symbol_ref, $file);

    # See comment block above
    push(@DynaLoader::dl_shared_objects, $file); # record files loaded
    return &$xs(@_);

sub bootstrap_inherit {
    require DynaLoader;
    goto \&DynaLoader::bootstrap_inherit;



=head1 NAME

XSLoader - Dynamically load C libraries into Perl code

=head1 VERSION

Version 0.24


    package YourPackage;
    require XSLoader;



This module defines a standard I<simplified> interface to the dynamic
linking mechanisms available on many platforms.  Its primary purpose is
to implement cheap automatic dynamic loading of Perl modules.

For a more complicated interface, see L<DynaLoader>.  Many (most)
features of C<DynaLoader> are not implemented in C<XSLoader>, like for
example the C<dl_load_flags>, not honored by C<XSLoader>.

=head2 Migration from C<DynaLoader>

A typical module using L<DynaLoader|DynaLoader> starts like this:

    package YourPackage;
    require DynaLoader;

    our @ISA = qw( OnePackage OtherPackage DynaLoader );
    our $VERSION = '0.01';
    bootstrap YourPackage $VERSION;

Change this to

    package YourPackage;
    use XSLoader;

    our @ISA = qw( OnePackage OtherPackage );
    our $VERSION = '0.01';
    XSLoader::load 'YourPackage', $VERSION;

In other words: replace C<require DynaLoader> by C<use XSLoader>, remove
C<DynaLoader> from C<@ISA>, change C<bootstrap> by C<XSLoader::load>.  Do not
forget to quote the name of your package on the C<XSLoader::load> line,
and add comma (C<,>) before the arguments (C<$VERSION> above).

Of course, if C<@ISA> contained only C<DynaLoader>, there is no need to have
the C<@ISA> assignment at all; moreover, if instead of C<our> one uses the
more backward-compatible

    use vars qw($VERSION @ISA);

one can remove this reference to C<@ISA> together with the C<@ISA> assignment.

If no C<$VERSION> was specified on the C<bootstrap> line, the last line becomes

    XSLoader::load 'YourPackage';

If the call to C<load> is from C<YourPackage>, then that can be further
simplified to


as C<load> will use C<caller> to determine the package.

=head2 Backward compatible boilerplate

If you want to have your cake and eat it too, you need a more complicated

    package YourPackage;
    use vars qw($VERSION @ISA);

    @ISA = qw( OnePackage OtherPackage );
    $VERSION = '0.01';
    eval {
       require XSLoader;
       XSLoader::load('YourPackage', $VERSION);
    } or do {
       require DynaLoader;
       push @ISA, 'DynaLoader';
       bootstrap YourPackage $VERSION;

The parentheses about C<XSLoader::load()> arguments are needed since we replaced
C<use XSLoader> by C<require>, so the compiler does not know that a function
C<XSLoader::load()> is present.

This boilerplate uses the low-overhead C<XSLoader> if present; if used with
an antique Perl which has no C<XSLoader>, it falls back to using C<DynaLoader>.

=head1 Order of initialization: early load()

I<Skip this section if the XSUB functions are supposed to be called from other
modules only; read it only if you call your XSUBs from the code in your module,
or have a C<BOOT:> section in your XS file (see L<perlxs/"The BOOT: Keyword">).
What is described here is equally applicable to the L<DynaLoader|DynaLoader>

A sufficiently complicated module using XS would have both Perl code (defined
in F<YourPackage.pm>) and XS code (defined in F<YourPackage.xs>).  If this
Perl code makes calls into this XS code, and/or this XS code makes calls to
the Perl code, one should be careful with the order of initialization.

The call to C<XSLoader::load()> (or C<bootstrap()>) calls the module's
bootstrap code. For modules build by F<xsubpp> (nearly all modules) this
has three side effects:


=item *

A sanity check is done to ensure that the versions of the F<.pm> and the
(compiled) F<.xs> parts are compatible. If C<$VERSION> was specified, this
is used for the check. If not specified, it defaults to
C<$XS_VERSION // $VERSION> (in the module's namespace)

=item *

the XSUBs are made accessible from Perl

=item *

if a C<BOOT:> section was present in the F<.xs> file, the code there is called.


Consequently, if the code in the F<.pm> file makes calls to these XSUBs, it is
convenient to have XSUBs installed before the Perl code is defined; for
example, this makes prototypes for XSUBs visible to this Perl code.
Alternatively, if the C<BOOT:> section makes calls to Perl functions (or
uses Perl variables) defined in the F<.pm> file, they must be defined prior to
the call to C<XSLoader::load()> (or C<bootstrap()>).

The first situation being much more frequent, it makes sense to rewrite the
boilerplate as

    package YourPackage;
    use XSLoader;
    use vars qw($VERSION @ISA);

    BEGIN {
       @ISA = qw( OnePackage OtherPackage );
       $VERSION = '0.01';

       # Put Perl code used in the BOOT: section here

       XSLoader::load 'YourPackage', $VERSION;

    # Put Perl code making calls into XSUBs here

=head2 The most hairy case

If the interdependence of your C<BOOT:> section and Perl code is
more complicated than this (e.g., the C<BOOT:> section makes calls to Perl
functions which make calls to XSUBs with prototypes), get rid of the C<BOOT:>
section altogether.  Replace it with a function C<onBOOT()>, and call it like

    package YourPackage;
    use XSLoader;
    use vars qw($VERSION @ISA);

    BEGIN {
       @ISA = qw( OnePackage OtherPackage );
       $VERSION = '0.01';
       XSLoader::load 'YourPackage', $VERSION;

    # Put Perl code used in onBOOT() function here; calls to XSUBs are
    # prototype-checked.


    # Put Perl initialization code assuming that XS is initialized here



=item C<Can't find '%s' symbol in %s>

B<(F)> The bootstrap symbol could not be found in the extension module.

=item C<Can't load '%s' for module %s: %s>

B<(F)> The loading or initialisation of the extension module failed.
The detailed error follows.

=item C<Undefined symbols present after loading %s: %s>

B<(W)> As the message says, some symbols stay undefined although the
extension module was correctly loaded and initialised. The list of undefined
symbols follows.



To reduce the overhead as much as possible, only one possible location
is checked to find the extension DLL (this location is where C<make install>
would put the DLL).  If not found, the search for the DLL is transparently
delegated to C<DynaLoader>, which looks for the DLL along the C<@INC> list.

In particular, this is applicable to the structure of C<@INC> used for testing
not-yet-installed extensions.  This means that running uninstalled extensions
may have much more overhead than running the same extensions after
C<make install>.


The new simpler way to call C<XSLoader::load()> with no arguments at all
does not work on Perl 5.8.4 and 5.8.5.

=head1 BUGS

Please report any bugs or feature requests via the perlbug(1) utility.

=head1 SEE ALSO


=head1 AUTHORS

Ilya Zakharevich originally extracted C<XSLoader> from C<DynaLoader>.

CPAN version is currently maintained by SE<eacute>bastien Aperghis-Tramoni

Previous maintainer was Michael G Schwern <schwern@pobox.com>.


Copyright (C) 1990-2011 by Larry Wall and others.

This program is free software; you can redistribute it and/or modify
it under the same terms as Perl itself.