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# Generated from XSLoader.pm.PL (resolved %Config::Config value)
package XSLoader;
$VERSION = "0.08";
#use strict;
# enable debug/trace messages from DynaLoader perl code # $dl_debug = $ENV{PERL_DL_DEBUG} || 0 unless defined $dl_debug;
my $dl_dlext = 'dll';
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) && !defined(&dl_error); package XSLoader;
sub load { package DynaLoader;
die q{XSLoader::load('Your::Module', $Your::Module::VERSION)} unless @_;
my($module) = $_[0];
# work with static linking too my $b = "$module\::bootstrap"; goto &$b if defined &$b;
goto retry unless $module and defined &dl_load_file;
my @modparts = split(/::/,$module); my $modfname = $modparts[-1];
my $modpname = join('/',@modparts); my $modlibname = (caller())[1]; my $c = @modparts; $modlibname =~ s,[\\/][^\\/]+$,, while $c--; # Q&D basename my $file = "$modlibname/auto/$modpname/$modfname.$dl_dlext";
# 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
goto retry if not -f $file or -s $bs;
my $bootname = "boot_$module"; $bootname =~ s/\W/_/g; @DynaLoader::dl_require_symbols = ($bootname);
my $boot_symbol_ref;
# 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
my @unresolved = dl_undef_symbols(); if (@unresolved) { require Carp; Carp::carp("Undefined symbols present after loading $file: @unresolved\n"); }
$boot_symbol_ref = dl_find_symbol($libref, $bootname) or do { require Carp; Carp::croak("Can't find '$bootname' symbol in $file\n"); };
push(@DynaLoader::dl_modules, $module); # record loaded module
boot: my $xs = dl_install_xsub("${module}::bootstrap", $boot_symbol_ref, $file);
# See comment block above push(@DynaLoader::dl_shared_objects, $file); # record files loaded return &$xs(@_);
retry: my $bootstrap_inherit = DynaLoader->can('bootstrap_inherit') || XSLoader->can('bootstrap_inherit'); goto &$bootstrap_inherit; }
# Versions of DynaLoader prior to 5.6.0 don't have this function. sub bootstrap_inherit { package DynaLoader;
my $module = $_[0]; local *DynaLoader::isa = *{"$module\::ISA"}; local @DynaLoader::isa = (@DynaLoader::isa, 'DynaLoader'); # Cannot goto due to delocalization. Will report errors on a wrong line? require DynaLoader; DynaLoader::bootstrap(@_); }
1;
__END__
=head1 NAME
XSLoader - Dynamically load C libraries into Perl code
=head1 VERSION
Version 0.08
=head1 SYNOPSIS
package YourPackage; use XSLoader;
XSLoader::load 'YourPackage', $YourPackage::VERSION;
=head1 DESCRIPTION
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';
=head2 Backward compatible boilerplate
If you want to have your cake and eat it too, you need a more complicated boilerplate.
package YourPackage; use vars qw($VERSION @ISA);
@ISA = qw( OnePackage OtherPackage ); $VERSION = '0.01'; eval { require XSLoader; XSLoader::load('YourPackage', $VERSION); 1; } or do { require DynaLoader; push @ISA, 'DynaLoader'; bootstrap YourPackage $VERSION; };
The parentheses about C<XSLoader::load()> arguments are needed since we replaced C<use XSLoader> by C<require>, so the compiler does not know that a function C<XSLoader::load()> is present.
This boilerplate uses the low-overhead C<XSLoader> if present; if used with an antic Perl which has no C<XSLoader>, it falls back to using C<DynaLoader>.
=head1 Order of initialization: early load()
I<Skip this section if the XSUB functions are supposed to be called from other modules only; read it only if you call your XSUBs from the code in your module, or have a C<BOOT:> section in your XS file (see L<perlxs/"The BOOT: Keyword">). What is described here is equally applicable to the L<DynaLoader|DynaLoader> interface.>
A sufficiently complicated module using XS would have both Perl code (defined in F<YourPackage.pm>) and XS code (defined in F<YourPackage.xs>). If this Perl code makes calls into this XS code, and/or this XS code makes calls to the Perl code, one should be careful with the order of initialization.
The call to C<XSLoader::load()> (or C<bootstrap()>) has three side effects:
=over
=item *
if C<$VERSION> was specified, a sanity check is done to ensure that the versions of the F<.pm> and the (compiled) F<.xs> parts are compatible;
=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.
=back
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', $VERSION; }
# Put Perl code making calls into XSUBs here
=head2 The most hairy case
If the interdependence of your C<BOOT:> section and Perl code is more complicated than this (e.g., the C<BOOT:> section makes calls to Perl functions which make calls to XSUBs with prototypes), get rid of the C<BOOT:> section altogether. Replace it with a function C<onBOOT()>, and call it like this:
package YourPackage; use XSLoader; use vars qw($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.
onBOOT;
# Put Perl initialization code assuming that XS is initialized here
=head1 DIAGNOSTICS
=over
=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.
=item C<XSLoader::load('Your::Module', $Your::Module::VERSION)>
B<(F)> You tried to invoke C<load()> without any argument. You must supply a module name, and optionally its version.
=back
=head1 LIMITATIONS
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>.
=head1 BUGS
Please report any bugs or feature requests via the perlbug(1) utility.
=head1 SEE ALSO
L<DynaLoader>
=head1 AUTHORS
Ilya Zakharevich originally extracted C<XSLoader> from C<DynaLoader>.
CPAN version is currently maintained by SE<eacute>bastien Aperghis-Tramoni E<lt>sebastien@aperghis.netE<gt>.
Previous maintainer was Michael G Schwern <[email protected]>.
=head1 COPYRIGHT
This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
=cut
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