3 # We require DynaLoader to make sure that mod2fname is loaded
4 eval { require DynaLoader };
6 1 while unlink "XSLoader.pm";
7 open OUT, '>', 'XSLoader.pm' or die $!;
9 # Generated from XSLoader.pm.PL (resolved %Config::Config value)
10 # This file is unique for every OS
22 # dlutils.c before 5.006 has this:
25 # dl_debug = SvIV( perl_get_sv("DynaLoader::dl_debug", 0x04) );
28 # where 0x04 is GV_ADDWARN, which causes a warning to be issued by the call
29 # into XS below, if DynaLoader.pm hasn't been loaded.
30 # It was changed to 0 in the commit(s) that added XSLoader to the core
31 # (9cf41c4d23a47c8b and its parent 9426adcd48655815)
32 # Hence to backport XSLoader to work silently with earlier DynaLoaders we need
33 # to ensure that the variable exists:
35 print OUT <<'EOT' if $] < 5.006;
37 # enable debug/trace messages from DynaLoader perl code
38 $dl_debug = $ENV{PERL_DL_DEBUG} || 0 unless defined $dl_debug;
43 # No prizes for guessing why we don't say 'bootstrap DynaLoader;' here.
44 # NOTE: All dl_*.xs (including dl_none.xs) define a dl_error() XSUB
45 boot_DynaLoader('DynaLoader') if defined(&boot_DynaLoader) &&
52 my ($caller, $modlibname) = caller();
61 # work with static linking too
62 my $boots = "$module\::bootstrap";
63 goto &$boots if defined &$boots;
65 goto \&XSLoader::bootstrap_inherit unless $module and defined &dl_load_file;
67 my @modparts = split(/::/,$module);
68 my $modfname = $modparts[-1];
72 # defined &DynaLoader::mod2fname catches most cases, except when
73 # cross-compiling to a system that defines mod2fname. Using
74 # $Config{d_libname_unique} is a best attempt at catching those cases.
75 print OUT <<'EOT' if defined &DynaLoader::mod2fname || $Config{d_libname_unique};
76 # Some systems have restrictions on files names for DLL's etc.
77 # mod2fname returns appropriate file base name (typically truncated)
78 # It may also edit @modparts if required.
79 $modfname = &DynaLoader::mod2fname(\@modparts) if defined &DynaLoader::mod2fname;
83 print OUT <<'EOT' if $^O eq 'os2';
85 # os2 static build can dynaload, but cannot dynaload Perl modules...
86 die 'Dynaloaded Perl modules are not available in this build of Perl' if $OS2::is_static;
91 my $modpname = join('/',@modparts);
92 my $c = () = split(/::/,$caller,-1);
93 $modlibname =~ s,[\\/][^\\/]+$,, while $c--; # Q&D basename
96 my $to_print = <<'EOT';
97 # Does this look like a relative path?
98 if ($modlibname !~ m{regexp}) {
101 $to_print =~ s~regexp~
102 $^O eq 'MSWin32' || $^O eq 'os2' || $^O eq 'cygwin' || $^O eq 'amigaos'
103 ? '^(?:[A-Za-z]:)?[\\\/]' # Optional drive letter
107 print OUT $to_print, <<'EOT';
108 # Someone may have a #line directive that changes the file name, or
109 # may be calling XSLoader::load from inside a string eval. We cer-
110 # tainly do not want to go loading some code that is not in @INC,
111 # as it could be untrusted.
113 # We could just fall back to DynaLoader here, but then the rest of
114 # this function would go untested in the perl core, since all @INC
115 # paths are relative during testing. That would be a time bomb
116 # waiting to happen, since bugs could be introduced into the code.
118 # So look through @INC to see if $modlibname is in it. A rela-
119 # tive $modlibname is not a common occurrence, so this block is
123 if ($_ eq $modlibname) {
127 # Not found. Fall back to DynaLoader.
128 goto \&XSLoader::bootstrap_inherit;
133 my $dl_dlext = quotemeta($Config::Config{'dlext'});
136 my \$file = "\$modlibname/auto/\$modpname/\$modfname.$dl_dlext";
141 # print STDERR "XSLoader::load for $module ($file)\n" if $dl_debug;
144 $bs =~ s/(\.\w+)?(;\d*)?$/\.bs/; # look for .bs 'beside' the library
146 if (-s $bs) { # only read file if it's not empty
147 # print STDERR "BS: $bs ($^O, $dlsrc)\n" if $dl_debug;
149 warn "$bs: $@\n" if $@;
150 goto \&XSLoader::bootstrap_inherit;
153 goto \&XSLoader::bootstrap_inherit if not -f $file;
155 my $bootname = "boot_$module";
156 $bootname =~ s/\W/_/g;
157 @DynaLoader::dl_require_symbols = ($bootname);
163 if ($^O eq 'darwin') {
164 my $extra_arg = ', 1 ' if $DynaLoader::VERSION ge '1.37';
166 if (\$boot_symbol_ref = dl_find_symbol( 0, \$bootname $extra_arg)) {
167 goto boot; #extension library has already been loaded, e.g. darwin
173 # Many dynamic extension loading problems will appear to come from
174 # this section of code: XYZ failed at line 123 of DynaLoader.pm.
175 # Often these errors are actually occurring in the initialisation
176 # C code of the extension XS file. Perl reports the error as being
177 # in this perl code simply because this was the last perl code
180 my $libref = dl_load_file($file, 0) or do {
182 Carp::croak("Can't load '$file' for module $module: " . dl_error());
184 push(@DynaLoader::dl_librefs,$libref); # record loaded object
187 my $dlsrc = $Config{dlsrc};
188 if ($dlsrc eq 'dl_freemint.xs' || $dlsrc eq 'dl_dld.xs') {
190 my @unresolved = dl_undef_symbols();
193 Carp::carp("Undefined symbols present after loading $file: @unresolved\n");
200 $boot_symbol_ref = dl_find_symbol($libref, $bootname) or do {
202 Carp::croak("Can't find '$bootname' symbol in $file\n");
205 push(@DynaLoader::dl_modules, $module); # record loaded module
208 my $xs = dl_install_xsub($boots, $boot_symbol_ref, $file);
210 # See comment block above
211 push(@DynaLoader::dl_shared_objects, $file); # record files loaded
216 # Can't test with DynaLoader->can('bootstrap_inherit') when building in the
217 # core, as XSLoader gets built before DynaLoader.
222 sub bootstrap_inherit {
224 goto \&DynaLoader::bootstrap_inherit;
231 sub bootstrap_inherit {
232 # Versions of DynaLoader prior to 5.6.0 don't have bootstrap_inherit.
236 local *DynaLoader::isa = *{"$module\::ISA"};
237 local @DynaLoader::isa = (@DynaLoader::isa, 'DynaLoader');
238 # Cannot goto due to delocalization. Will report errors on a wrong line?
240 DynaLoader::bootstrap(@_);
254 XSLoader - Dynamically load C libraries into Perl code
269 This module defines a standard I<simplified> interface to the dynamic
270 linking mechanisms available on many platforms. Its primary purpose is
271 to implement cheap automatic dynamic loading of Perl modules.
273 For a more complicated interface, see L<DynaLoader>. Many (most)
274 features of C<DynaLoader> are not implemented in C<XSLoader>, like for
275 example the C<dl_load_flags>, not honored by C<XSLoader>.
277 =head2 Migration from C<DynaLoader>
279 A typical module using L<DynaLoader|DynaLoader> starts like this:
284 our @ISA = qw( OnePackage OtherPackage DynaLoader );
285 our $VERSION = '0.01';
286 bootstrap YourPackage $VERSION;
293 our @ISA = qw( OnePackage OtherPackage );
294 our $VERSION = '0.01';
295 XSLoader::load 'YourPackage', $VERSION;
297 In other words: replace C<require DynaLoader> by C<use XSLoader>, remove
298 C<DynaLoader> from C<@ISA>, change C<bootstrap> by C<XSLoader::load>. Do not
299 forget to quote the name of your package on the C<XSLoader::load> line,
300 and add comma (C<,>) before the arguments (C<$VERSION> above).
302 Of course, if C<@ISA> contained only C<DynaLoader>, there is no need to have
303 the C<@ISA> assignment at all; moreover, if instead of C<our> one uses the
304 more backward-compatible
306 use vars qw($VERSION @ISA);
308 one can remove this reference to C<@ISA> together with the C<@ISA> assignment.
310 If no C<$VERSION> was specified on the C<bootstrap> line, the last line becomes
312 XSLoader::load 'YourPackage';
314 If the call to C<load> is from C<YourPackage>, then that can be further
319 as C<load> will use C<caller> to determine the package.
321 =head2 Backward compatible boilerplate
323 If you want to have your cake and eat it too, you need a more complicated
327 use vars qw($VERSION @ISA);
329 @ISA = qw( OnePackage OtherPackage );
333 XSLoader::load('YourPackage', $VERSION);
337 push @ISA, 'DynaLoader';
338 bootstrap YourPackage $VERSION;
341 The parentheses about C<XSLoader::load()> arguments are needed since we replaced
342 C<use XSLoader> by C<require>, so the compiler does not know that a function
343 C<XSLoader::load()> is present.
345 This boilerplate uses the low-overhead C<XSLoader> if present; if used with
346 an antique Perl which has no C<XSLoader>, it falls back to using C<DynaLoader>.
348 =head1 Order of initialization: early load()
350 I<Skip this section if the XSUB functions are supposed to be called from other
351 modules only; read it only if you call your XSUBs from the code in your module,
352 or have a C<BOOT:> section in your XS file (see L<perlxs/"The BOOT: Keyword">).
353 What is described here is equally applicable to the L<DynaLoader|DynaLoader>
356 A sufficiently complicated module using XS would have both Perl code (defined
357 in F<YourPackage.pm>) and XS code (defined in F<YourPackage.xs>). If this
358 Perl code makes calls into this XS code, and/or this XS code makes calls to
359 the Perl code, one should be careful with the order of initialization.
361 The call to C<XSLoader::load()> (or C<bootstrap()>) calls the module's
362 bootstrap code. For modules build by F<xsubpp> (nearly all modules) this
363 has three side effects:
369 A sanity check is done to ensure that the versions of the F<.pm> and the
370 (compiled) F<.xs> parts are compatible. If C<$VERSION> was specified, this
371 is used for the check. If not specified, it defaults to
372 C<$XS_VERSION // $VERSION> (in the module's namespace)
376 the XSUBs are made accessible from Perl
380 if a C<BOOT:> section was present in the F<.xs> file, the code there is called.
384 Consequently, if the code in the F<.pm> file makes calls to these XSUBs, it is
385 convenient to have XSUBs installed before the Perl code is defined; for
386 example, this makes prototypes for XSUBs visible to this Perl code.
387 Alternatively, if the C<BOOT:> section makes calls to Perl functions (or
388 uses Perl variables) defined in the F<.pm> file, they must be defined prior to
389 the call to C<XSLoader::load()> (or C<bootstrap()>).
391 The first situation being much more frequent, it makes sense to rewrite the
396 use vars qw($VERSION @ISA);
399 @ISA = qw( OnePackage OtherPackage );
402 # Put Perl code used in the BOOT: section here
404 XSLoader::load 'YourPackage', $VERSION;
407 # Put Perl code making calls into XSUBs here
409 =head2 The most hairy case
411 If the interdependence of your C<BOOT:> section and Perl code is
412 more complicated than this (e.g., the C<BOOT:> section makes calls to Perl
413 functions which make calls to XSUBs with prototypes), get rid of the C<BOOT:>
414 section altogether. Replace it with a function C<onBOOT()>, and call it like
419 use vars qw($VERSION @ISA);
422 @ISA = qw( OnePackage OtherPackage );
424 XSLoader::load 'YourPackage', $VERSION;
427 # Put Perl code used in onBOOT() function here; calls to XSUBs are
432 # Put Perl initialization code assuming that XS is initialized here
439 =item C<Can't find '%s' symbol in %s>
441 B<(F)> The bootstrap symbol could not be found in the extension module.
443 =item C<Can't load '%s' for module %s: %s>
445 B<(F)> The loading or initialisation of the extension module failed.
446 The detailed error follows.
448 =item C<Undefined symbols present after loading %s: %s>
450 B<(W)> As the message says, some symbols stay undefined although the
451 extension module was correctly loaded and initialised. The list of undefined
458 To reduce the overhead as much as possible, only one possible location
459 is checked to find the extension DLL (this location is where C<make install>
460 would put the DLL). If not found, the search for the DLL is transparently
461 delegated to C<DynaLoader>, which looks for the DLL along the C<@INC> list.
463 In particular, this is applicable to the structure of C<@INC> used for testing
464 not-yet-installed extensions. This means that running uninstalled extensions
465 may have much more overhead than running the same extensions after
471 The new simpler way to call C<XSLoader::load()> with no arguments at all
472 does not work on Perl 5.8.4 and 5.8.5.
477 Please report any bugs or feature requests via the perlbug(1) utility.
487 Ilya Zakharevich originally extracted C<XSLoader> from C<DynaLoader>.
489 CPAN version is currently maintained by SE<eacute>bastien Aperghis-Tramoni
490 E<lt>sebastien@aperghis.netE<gt>.
492 Previous maintainer was Michael G Schwern <schwern@pobox.com>.
495 =head1 COPYRIGHT & LICENSE
497 Copyright (C) 1990-2011 by Larry Wall and others.
499 This program is free software; you can redistribute it and/or modify
500 it under the same terms as Perl itself.