1 # Generated from XSLoader.pm.PL (resolved %Config::Config value)
9 # enable debug/trace messages from DynaLoader perl code
10 # $dl_debug = $ENV{PERL_DL_DEBUG} || 0 unless defined $dl_debug;
16 # No prizes for guessing why we don't say 'bootstrap DynaLoader;' here.
17 # NOTE: All dl_*.xs (including dl_none.xs) define a dl_error() XSUB
18 boot_DynaLoader
('DynaLoader') if defined(&boot_DynaLoader
) &&
25 die q{XSLoader::load('Your::Module', $Your::Module::VERSION)} unless @_;
29 # work with static linking too
30 my $b = "$module\::bootstrap";
31 goto &$b if defined &$b;
33 goto retry unless $module and defined &dl_load_file;
35 my @modparts = split(/::/,$module);
36 my $modfname = $modparts[-1];
38 my $modpname = join('/',@modparts);
39 my $modlibname = (caller())[1];
41 $modlibname =~ s,[\\/][^\\/]+$,, while $c--; # Q&D basename
42 my $file = "$modlibname/auto/$modpname/$modfname.$dl_dlext";
44 # print STDERR "XSLoader::load for $module ($file)\n" if $dl_debug;
47 $bs =~ s/(\.\w+)?(;\d*)?$/\.bs/; # look for .bs 'beside' the library
49 goto retry if not -f $file or -s $bs;
51 my $bootname = "boot_$module";
52 $bootname =~ s/\W/_/g;
53 @DynaLoader::dl_require_symbols = ($bootname);
57 if ($^O eq 'darwin') {
58 if ($boot_symbol_ref = dl_find_symbol(0, $bootname)) {
59 goto boot; #extension library has already been loaded, e.g. darwin
63 # Many dynamic extension loading problems will appear to come from
64 # this section of code: XYZ failed at line 123 of DynaLoader.pm.
65 # Often these errors are actually occurring in the initialisation
66 # C code of the extension XS file. Perl reports the error as being
67 # in this perl code simply because this was the last perl code
70 my $libref = dl_load_file($file, 0) or do {
72 Carp::croak("Can't load '$file' for module $module: " . dl_error());
74 push(@DynaLoader::dl_librefs,$libref); # record loaded object
76 my @unresolved = dl_undef_symbols();
79 Carp::carp("Undefined symbols present after loading $file: @unresolved\n");
82 $boot_symbol_ref = dl_find_symbol($libref, $bootname) or do {
84 Carp::croak("Can't find '$bootname' symbol in $file\n");
87 push(@DynaLoader::dl_modules, $module); # record loaded module
90 my $xs = dl_install_xsub("${module}::bootstrap", $boot_symbol_ref, $file);
92 # See comment block above
93 push(@DynaLoader::dl_shared_objects, $file); # record files loaded
97 my $bootstrap_inherit = DynaLoader->can('bootstrap_inherit') ||
98 XSLoader->can('bootstrap_inherit');
99 goto &$bootstrap_inherit;
102 # Versions of DynaLoader prior to 5.6.0 don't have this function.
103 sub bootstrap_inherit {
107 local *DynaLoader::isa = *{"$module\::ISA"};
108 local @DynaLoader::isa = (@DynaLoader::isa, 'DynaLoader');
109 # Cannot goto due to delocalization. Will report errors on a wrong line?
111 DynaLoader::bootstrap(@_);
121 XSLoader - Dynamically load C libraries into Perl code
132 XSLoader::load 'YourPackage', $YourPackage::VERSION;
136 This module defines a standard I<simplified> interface to the dynamic
137 linking mechanisms available on many platforms. Its primary purpose is
138 to implement cheap automatic dynamic loading of Perl modules.
140 For a more complicated interface, see L<DynaLoader>. Many (most)
141 features of C<DynaLoader> are not implemented in C<XSLoader>, like for
142 example the C<dl_load_flags>, not honored by C<XSLoader>.
144 =head2 Migration from C<DynaLoader>
146 A typical module using L<DynaLoader|DynaLoader> starts like this:
151 our @ISA = qw( OnePackage OtherPackage DynaLoader );
152 our $VERSION = '0.01';
153 bootstrap YourPackage
$VERSION;
160 our @ISA = qw( OnePackage OtherPackage );
161 our $VERSION = '0.01';
162 XSLoader
::load
'YourPackage', $VERSION;
164 In other words
: replace C
<require DynaLoader
> by C
<use XSLoader
>, remove
165 C
<DynaLoader
> from C
<@ISA>, change C
<bootstrap
> by C
<XSLoader
::load
>. Do
not
166 forget to quote the name of your
package on the C
<XSLoader
::load
> line
,
167 and add comma
(C
<,>) before the arguments
(C
<$VERSION> above
).
169 Of course
, if C
<@ISA> contained only C
<DynaLoader
>, there is
no need to have
170 the C
<@ISA> assignment at all
; moreover
, if instead of C
<our> one uses the
171 more backward
-compatible
173 use vars
qw($VERSION @ISA);
175 one can remove this reference to C<@ISA> together with the C<@ISA> assignment.
177 If no C<$VERSION> was specified on the C<bootstrap> line, the last line becomes
179 XSLoader::load 'YourPackage';
181 =head2 Backward compatible boilerplate
183 If you want to have your cake and eat it too, you need a more complicated
187 use vars qw($VERSION @ISA);
189 @ISA = qw( OnePackage OtherPackage );
193 XSLoader
::load
('YourPackage', $VERSION);
197 push @ISA, 'DynaLoader';
198 bootstrap YourPackage
$VERSION;
201 The parentheses about C
<XSLoader
::load
()> arguments are needed since we replaced
202 C
<use XSLoader
> by C
<require>, so the compiler does
not know that a function
203 C
<XSLoader
::load
()> is present
.
205 This boilerplate uses the low
-overhead C
<XSLoader
> if present
; if used with
206 an antic Perl which has
no C
<XSLoader
>, it falls back to using C
<DynaLoader
>.
208 =head1 Order of initialization: early load()
210 I<Skip this section if the XSUB functions are supposed to be called from other
211 modules only; read it only if you call your XSUBs from the code in your module,
212 or have a C<BOOT:> section in your XS file (see L<perlxs/"The BOOT: Keyword">).
213 What is described here is equally applicable to the L<DynaLoader|DynaLoader>
216 A sufficiently complicated module using XS would have both Perl code (defined
217 in F<YourPackage.pm>) and XS code (defined in F<YourPackage.xs>). If this
218 Perl code makes calls into this XS code, and/or this XS code makes calls to
219 the Perl code, one should be careful with the order of initialization.
221 The call to C<XSLoader::load()> (or C<bootstrap()>) has three side effects:
227 if C<$VERSION> was specified, a sanity check is done to ensure that the
228 versions of the F<.pm> and the (compiled) F<.xs> parts are compatible;
232 the XSUBs are made accessible from Perl;
236 if a C<BOOT:> section was present in the F<.xs> file, the code there is called.
240 Consequently, if the code in the F<.pm> file makes calls to these XSUBs, it is
241 convenient to have XSUBs installed before the Perl code is defined; for
242 example, this makes prototypes for XSUBs visible to this Perl code.
243 Alternatively, if the C<BOOT:> section makes calls to Perl functions (or
244 uses Perl variables) defined in the F<.pm> file, they must be defined prior to
245 the call to C<XSLoader::load()> (or C<bootstrap()>).
247 The first situation being much more frequent, it makes sense to rewrite the
252 use vars qw($VERSION @ISA);
255 @ISA = qw( OnePackage OtherPackage );
258 # Put Perl code used in the BOOT: section here
260 XSLoader::load 'YourPackage', $VERSION;
263 # Put Perl code making calls into XSUBs here
265 =head2 The most hairy case
267 If the interdependence of your C<BOOT:> section and Perl code is
268 more complicated than this (e.g., the C<BOOT:> section makes calls to Perl
269 functions which make calls to XSUBs with prototypes), get rid of the C<BOOT:>
270 section altogether. Replace it with a function C<onBOOT()>, and call it like
275 use vars qw($VERSION @ISA);
278 @ISA = qw( OnePackage OtherPackage );
280 XSLoader::load 'YourPackage', $VERSION;
283 # Put Perl code used in onBOOT() function here; calls to XSUBs are
288 # Put Perl initialization code assuming that XS is initialized here
295 =item Can't find '%s' symbol in %s
297 B<(F)> The bootstrap symbol could not be found in the extension module.
299 =item Can't load '%s' for module %s: %s
301 B<(F)> The loading or initialisation of the extension module failed.
302 The detailed error follows.
304 =item Undefined symbols present after loading %s: %s
306 B<(W)> As the message says, some symbols stay undefined although the
307 extension module was correctly loaded and initialised. The list of undefined
310 =item XSLoader::load('Your::Module', $Your::Module::VERSION)
312 B<(F)> You tried to invoke C<load()> without any argument. You must supply
313 a module name, and optionally its version.
320 To reduce the overhead as much as possible, only one possible location
321 is checked to find the extension DLL (this location is where C<make install>
322 would put the DLL). If not found, the search for the DLL is transparently
323 delegated to C<DynaLoader>, which looks for the DLL along the C<@INC> list.
325 In particular, this is applicable to the structure of C<@INC> used for testing
326 not-yet-installed extensions. This means that running uninstalled extensions
327 may have much more overhead than running the same extensions after
333 Please report any bugs or feature requests via the perlbug(1) utility.
343 Ilya Zakharevich originally extracted C<XSLoader> from C<DynaLoader>.
345 CPAN version is currently maintained by SE<eacute>bastien Aperghis-Tramoni
346 E<lt>sebastien@aperghis.netE<gt>
348 Previous maintainer was Michael G Schwern <schwern@pobox.com>
353 This program is free software; you can redistribute it and/or modify
354 it under the same terms as Perl itself.