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);
85 if ($^O eq 'darwin') {
86 if ($boot_symbol_ref = dl_find_symbol(0, $bootname)) {
87 goto boot; #extension library has already been loaded, e.g. darwin
91 # Many dynamic extension loading problems will appear to come from
92 # this section of code: XYZ failed at line 123 of DynaLoader.pm.
93 # Often these errors are actually occurring in the initialisation
94 # C code of the extension XS file. Perl reports the error as being
95 # in this perl code simply because this was the last perl code
98 my $libref = dl_load_file($file, 0) or do {
100 Carp::croak("Can't load '$file' for module $module: " . dl_error());
102 push(@DynaLoader::dl_librefs,$libref); # record loaded object
104 my @unresolved = dl_undef_symbols();
107 Carp::carp("Undefined symbols present after loading $file: @unresolved\n");
110 $boot_symbol_ref = dl_find_symbol($libref, $bootname) or do {
112 Carp::croak("Can't find '$bootname' symbol in $file\n");
115 push(@DynaLoader::dl_modules, $module); # record loaded module
118 my $xs = dl_install_xsub("${module}::bootstrap", $boot_symbol_ref, $file);
120 # See comment block above
121 push(@DynaLoader::dl_shared_objects, $file); # record files loaded
125 my $bootstrap_inherit = DynaLoader->can('bootstrap_inherit') ||
126 XSLoader->can('bootstrap_inherit');
127 goto &$bootstrap_inherit;
130 # Versions of DynaLoader prior to 5.6.0 don't have this function.
131 sub bootstrap_inherit {
135 local *DynaLoader::isa = *{"$module\::ISA"};
136 local @DynaLoader::isa = (@DynaLoader::isa, 'DynaLoader');
137 # Cannot goto due to delocalization. Will report errors on a wrong line?
139 DynaLoader::bootstrap(@_);
149 XSLoader - Dynamically load C libraries into Perl code
160 XSLoader::load 'YourPackage', $YourPackage::VERSION;
164 This module defines a standard I<simplified> interface to the dynamic
165 linking mechanisms available on many platforms. Its primary purpose is
166 to implement cheap automatic dynamic loading of Perl modules.
168 For a more complicated interface, see L<DynaLoader>. Many (most)
169 features of C<DynaLoader> are not implemented in C<XSLoader>, like for
170 example the C<dl_load_flags>, not honored by C<XSLoader>.
172 =head2 Migration from C<DynaLoader>
174 A typical module using L<DynaLoader|DynaLoader> starts like this:
179 our @ISA = qw( OnePackage OtherPackage DynaLoader );
180 our $VERSION = '0.01';
181 bootstrap YourPackage $VERSION;
188 our @ISA = qw( OnePackage OtherPackage );
189 our $VERSION = '0.01';
190 XSLoader::load 'YourPackage', $VERSION;
192 In other words: replace C<require DynaLoader> by C<use XSLoader>, remove
193 C<DynaLoader> from C<@ISA>, change C<bootstrap> by C<XSLoader::load>. Do not
194 forget to quote the name of your package on the C<XSLoader::load> line,
195 and add comma (C<,>) before the arguments (C<$VERSION> above).
197 Of course, if C<@ISA> contained only C<DynaLoader>, there is no need to have
198 the C<@ISA> assignment at all; moreover, if instead of C<our> one uses the
199 more backward-compatible
201 use vars qw($VERSION @ISA);
203 one can remove this reference to C<@ISA> together with the C<@ISA> assignment.
205 If no C<$VERSION> was specified on the C<bootstrap> line, the last line becomes
207 XSLoader::load 'YourPackage';
209 =head2 Backward compatible boilerplate
211 If you want to have your cake and eat it too, you need a more complicated
215 use vars qw($VERSION @ISA);
217 @ISA = qw( OnePackage OtherPackage );
221 XSLoader::load('YourPackage', $VERSION);
225 push @ISA, 'DynaLoader';
226 bootstrap YourPackage $VERSION;
229 The parentheses about C<XSLoader::load()> arguments are needed since we replaced
230 C<use XSLoader> by C<require>, so the compiler does not know that a function
231 C<XSLoader::load()> is present.
233 This boilerplate uses the low-overhead C<XSLoader> if present; if used with
234 an antic Perl which has no C<XSLoader>, it falls back to using C<DynaLoader>.
236 =head1 Order of initialization: early load()
238 I<Skip this section if the XSUB functions are supposed to be called from other
239 modules only; read it only if you call your XSUBs from the code in your module,
240 or have a C<BOOT:> section in your XS file (see L<perlxs/"The BOOT: Keyword">).
241 What is described here is equally applicable to the L<DynaLoader|DynaLoader>
244 A sufficiently complicated module using XS would have both Perl code (defined
245 in F<YourPackage.pm>) and XS code (defined in F<YourPackage.xs>). If this
246 Perl code makes calls into this XS code, and/or this XS code makes calls to
247 the Perl code, one should be careful with the order of initialization.
249 The call to C<XSLoader::load()> (or C<bootstrap()>) has three side effects:
255 if C<$VERSION> was specified, a sanity check is done to ensure that the
256 versions of the F<.pm> and the (compiled) F<.xs> parts are compatible;
260 the XSUBs are made accessible from Perl;
264 if a C<BOOT:> section was present in the F<.xs> file, the code there is called.
268 Consequently, if the code in the F<.pm> file makes calls to these XSUBs, it is
269 convenient to have XSUBs installed before the Perl code is defined; for
270 example, this makes prototypes for XSUBs visible to this Perl code.
271 Alternatively, if the C<BOOT:> section makes calls to Perl functions (or
272 uses Perl variables) defined in the F<.pm> file, they must be defined prior to
273 the call to C<XSLoader::load()> (or C<bootstrap()>).
275 The first situation being much more frequent, it makes sense to rewrite the
280 use vars qw($VERSION @ISA);
283 @ISA = qw( OnePackage OtherPackage );
286 # Put Perl code used in the BOOT: section here
288 XSLoader::load 'YourPackage', $VERSION;
291 # Put Perl code making calls into XSUBs here
293 =head2 The most hairy case
295 If the interdependence of your C<BOOT:> section and Perl code is
296 more complicated than this (e.g., the C<BOOT:> section makes calls to Perl
297 functions which make calls to XSUBs with prototypes), get rid of the C<BOOT:>
298 section altogether. Replace it with a function C<onBOOT()>, and call it like
303 use vars qw($VERSION @ISA);
306 @ISA = qw( OnePackage OtherPackage );
308 XSLoader::load 'YourPackage', $VERSION;
311 # Put Perl code used in onBOOT() function here; calls to XSUBs are
316 # Put Perl initialization code assuming that XS is initialized here
323 =item C<Can't find '%s' symbol in %s>
325 B<(F)> The bootstrap symbol could not be found in the extension module.
327 =item C<Can't load '%s' for module %s: %s>
329 B<(F)> The loading or initialisation of the extension module failed.
330 The detailed error follows.
332 =item C<Undefined symbols present after loading %s: %s>
334 B<(W)> As the message says, some symbols stay undefined although the
335 extension module was correctly loaded and initialised. The list of undefined
338 =item C<XSLoader::load('Your::Module', $Your::Module::VERSION)>
340 B<(F)> You tried to invoke C<load()> without any argument. You must supply
341 a module name, and optionally its version.
348 To reduce the overhead as much as possible, only one possible location
349 is checked to find the extension DLL (this location is where C<make install>
350 would put the DLL). If not found, the search for the DLL is transparently
351 delegated to C<DynaLoader>, which looks for the DLL along the C<@INC> list.
353 In particular, this is applicable to the structure of C<@INC> used for testing
354 not-yet-installed extensions. This means that running uninstalled extensions
355 may have much more overhead than running the same extensions after
361 Please report any bugs or feature requests via the perlbug(1) utility.
371 Ilya Zakharevich originally extracted C<XSLoader> from C<DynaLoader>.
373 CPAN version is currently maintained by SE<eacute>bastien Aperghis-Tramoni
374 E<lt>sebastien@aperghis.netE<gt>.
376 Previous maintainer was Michael G Schwern <schwern@pobox.com>.
381 This program is free software; you can redistribute it and/or modify
382 it under the same terms as Perl itself.