11 1 while unlink "XSLoader.pm";
12 open OUT, ">XSLoader.pm" or die $!;
14 # Generated from XSLoader.pm.PL (resolved %Config::Config value)
22 # enable debug/trace messages from DynaLoader perl code
23 # $dl_debug = $ENV{PERL_DL_DEBUG} || 0 unless defined $dl_debug;
27 print OUT ' my $dl_dlext = ', to_string($Config::Config{'dlext'}), ";\n" ;
33 # No prizes for guessing why we don't say 'bootstrap DynaLoader;' here.
34 # NOTE: All dl_*.xs (including dl_none.xs) define a dl_error() XSUB
35 boot_DynaLoader('DynaLoader') if defined(&boot_DynaLoader) &&
42 die q{XSLoader::load('Your::Module', $Your::Module::VERSION)} unless @_;
46 # work with static linking too
47 my $b = "$module\::bootstrap";
48 goto &$b if defined &$b;
50 goto retry unless $module and defined &dl_load_file;
52 my @modparts = split(/::/,$module);
53 my $modfname = $modparts[-1];
57 print OUT <<'EOT' if defined &DynaLoader::mod2fname;
58 # Some systems have restrictions on files names for DLL's etc.
59 # mod2fname returns appropriate file base name (typically truncated)
60 # It may also edit @modparts if required.
61 $modfname = &mod2fname(\@modparts) if defined &mod2fname;
66 my $modpname = join('/',@modparts);
67 my $modlibname = (caller())[1];
69 $modlibname =~ s,[\\/][^\\/]+$,, while $c--; # Q&D basename
70 my $file = "$modlibname/auto/$modpname/$modfname.$dl_dlext";
72 # print STDERR "XSLoader::load for $module ($file)\n" if $dl_debug;
75 $bs =~ s/(\.\w+)?(;\d*)?$/\.bs/; # look for .bs 'beside' the library
77 goto retry if not -f $file or -s $bs;
79 my $bootname = "boot_$module";
80 $bootname =~ s/\W/_/g;
81 @DynaLoader::dl_require_symbols = ($bootname);
87 if ($^O eq 'darwin') {
89 if ($boot_symbol_ref = dl_find_symbol(0, $bootname)) {
90 goto boot; #extension library has already been loaded, e.g. darwin
96 # Many dynamic extension loading problems will appear to come from
97 # this section of code: XYZ failed at line 123 of DynaLoader.pm.
98 # Often these errors are actually occurring in the initialisation
99 # C code of the extension XS file. Perl reports the error as being
100 # in this perl code simply because this was the last perl code
103 my $libref = dl_load_file($file, 0) or do {
105 Carp::croak("Can't load '$file' for module $module: " . dl_error());
107 push(@DynaLoader::dl_librefs,$libref); # record loaded object
109 my @unresolved = dl_undef_symbols();
112 Carp::carp("Undefined symbols present after loading $file: @unresolved\n");
115 $boot_symbol_ref = dl_find_symbol($libref, $bootname) or do {
117 Carp::croak("Can't find '$bootname' symbol in $file\n");
120 push(@DynaLoader::dl_modules, $module); # record loaded module
123 my $xs = dl_install_xsub("${module}::bootstrap", $boot_symbol_ref, $file);
125 # See comment block above
126 push(@DynaLoader::dl_shared_objects, $file); # record files loaded
130 my $bootstrap_inherit = DynaLoader->can('bootstrap_inherit') ||
131 XSLoader->can('bootstrap_inherit');
132 goto &$bootstrap_inherit;
135 # Versions of DynaLoader prior to 5.6.0 don't have this function.
136 sub bootstrap_inherit {
140 local *DynaLoader::isa = *{"$module\::ISA"};
141 local @DynaLoader::isa = (@DynaLoader::isa, 'DynaLoader');
142 # Cannot goto due to delocalization. Will report errors on a wrong line?
144 DynaLoader::bootstrap(@_);
154 XSLoader - Dynamically load C libraries into Perl code
165 XSLoader::load 'YourPackage', $YourPackage::VERSION;
169 This module defines a standard I<simplified> interface to the dynamic
170 linking mechanisms available on many platforms. Its primary purpose is
171 to implement cheap automatic dynamic loading of Perl modules.
173 For a more complicated interface, see L<DynaLoader>. Many (most)
174 features of C<DynaLoader> are not implemented in C<XSLoader>, like for
175 example the C<dl_load_flags>, not honored by C<XSLoader>.
177 =head2 Migration from C<DynaLoader>
179 A typical module using L<DynaLoader|DynaLoader> starts like this:
184 our @ISA = qw( OnePackage OtherPackage DynaLoader );
185 our $VERSION = '0.01';
186 bootstrap YourPackage $VERSION;
193 our @ISA = qw( OnePackage OtherPackage );
194 our $VERSION = '0.01';
195 XSLoader::load 'YourPackage', $VERSION;
197 In other words: replace C<require DynaLoader> by C<use XSLoader>, remove
198 C<DynaLoader> from C<@ISA>, change C<bootstrap> by C<XSLoader::load>. Do not
199 forget to quote the name of your package on the C<XSLoader::load> line,
200 and add comma (C<,>) before the arguments (C<$VERSION> above).
202 Of course, if C<@ISA> contained only C<DynaLoader>, there is no need to have
203 the C<@ISA> assignment at all; moreover, if instead of C<our> one uses the
204 more backward-compatible
206 use vars qw($VERSION @ISA);
208 one can remove this reference to C<@ISA> together with the C<@ISA> assignment.
210 If no C<$VERSION> was specified on the C<bootstrap> line, the last line becomes
212 XSLoader::load 'YourPackage';
214 =head2 Backward compatible boilerplate
216 If you want to have your cake and eat it too, you need a more complicated
220 use vars qw($VERSION @ISA);
222 @ISA = qw( OnePackage OtherPackage );
226 XSLoader::load('YourPackage', $VERSION);
230 push @ISA, 'DynaLoader';
231 bootstrap YourPackage $VERSION;
234 The parentheses about C<XSLoader::load()> arguments are needed since we replaced
235 C<use XSLoader> by C<require>, so the compiler does not know that a function
236 C<XSLoader::load()> is present.
238 This boilerplate uses the low-overhead C<XSLoader> if present; if used with
239 an antic Perl which has no C<XSLoader>, it falls back to using C<DynaLoader>.
241 =head1 Order of initialization: early load()
243 I<Skip this section if the XSUB functions are supposed to be called from other
244 modules only; read it only if you call your XSUBs from the code in your module,
245 or have a C<BOOT:> section in your XS file (see L<perlxs/"The BOOT: Keyword">).
246 What is described here is equally applicable to the L<DynaLoader|DynaLoader>
249 A sufficiently complicated module using XS would have both Perl code (defined
250 in F<YourPackage.pm>) and XS code (defined in F<YourPackage.xs>). If this
251 Perl code makes calls into this XS code, and/or this XS code makes calls to
252 the Perl code, one should be careful with the order of initialization.
254 The call to C<XSLoader::load()> (or C<bootstrap()>) has three side effects:
260 if C<$VERSION> was specified, a sanity check is done to ensure that the
261 versions of the F<.pm> and the (compiled) F<.xs> parts are compatible;
265 the XSUBs are made accessible from Perl;
269 if a C<BOOT:> section was present in the F<.xs> file, the code there is called.
273 Consequently, if the code in the F<.pm> file makes calls to these XSUBs, it is
274 convenient to have XSUBs installed before the Perl code is defined; for
275 example, this makes prototypes for XSUBs visible to this Perl code.
276 Alternatively, if the C<BOOT:> section makes calls to Perl functions (or
277 uses Perl variables) defined in the F<.pm> file, they must be defined prior to
278 the call to C<XSLoader::load()> (or C<bootstrap()>).
280 The first situation being much more frequent, it makes sense to rewrite the
285 use vars qw($VERSION @ISA);
288 @ISA = qw( OnePackage OtherPackage );
291 # Put Perl code used in the BOOT: section here
293 XSLoader::load 'YourPackage', $VERSION;
296 # Put Perl code making calls into XSUBs here
298 =head2 The most hairy case
300 If the interdependence of your C<BOOT:> section and Perl code is
301 more complicated than this (e.g., the C<BOOT:> section makes calls to Perl
302 functions which make calls to XSUBs with prototypes), get rid of the C<BOOT:>
303 section altogether. Replace it with a function C<onBOOT()>, and call it like
308 use vars qw($VERSION @ISA);
311 @ISA = qw( OnePackage OtherPackage );
313 XSLoader::load 'YourPackage', $VERSION;
316 # Put Perl code used in onBOOT() function here; calls to XSUBs are
321 # Put Perl initialization code assuming that XS is initialized here
328 =item C<Can't find '%s' symbol in %s>
330 B<(F)> The bootstrap symbol could not be found in the extension module.
332 =item C<Can't load '%s' for module %s: %s>
334 B<(F)> The loading or initialisation of the extension module failed.
335 The detailed error follows.
337 =item C<Undefined symbols present after loading %s: %s>
339 B<(W)> As the message says, some symbols stay undefined although the
340 extension module was correctly loaded and initialised. The list of undefined
343 =item C<XSLoader::load('Your::Module', $Your::Module::VERSION)>
345 B<(F)> You tried to invoke C<load()> without any argument. You must supply
346 a module name, and optionally its version.
353 To reduce the overhead as much as possible, only one possible location
354 is checked to find the extension DLL (this location is where C<make install>
355 would put the DLL). If not found, the search for the DLL is transparently
356 delegated to C<DynaLoader>, which looks for the DLL along the C<@INC> list.
358 In particular, this is applicable to the structure of C<@INC> used for testing
359 not-yet-installed extensions. This means that running uninstalled extensions
360 may have much more overhead than running the same extensions after
366 Please report any bugs or feature requests via the perlbug(1) utility.
376 Ilya Zakharevich originally extracted C<XSLoader> from C<DynaLoader>.
378 CPAN version is currently maintained by SE<eacute>bastien Aperghis-Tramoni
379 E<lt>sebastien@aperghis.netE<gt>.
381 Previous maintainer was Michael G Schwern <schwern@pobox.com>.
386 This program is free software; you can redistribute it and/or modify
387 it under the same terms as Perl itself.