1: # Generated from XSLoader.pm.PL (resolved %Config::Config value)
2: # This file is unique for every OS
3: 
4: package XSLoader;
5: 
6: $VERSION = "0.24";
7: 
8: #use strict;
9: 
10: package DynaLoader;
11: 
12: # No prizes for guessing why we don't say 'bootstrap DynaLoader;' here.
13: # NOTE: All dl_*.xs (including dl_none.xs) define a dl_error() XSUB
14: boot_DynaLoader('DynaLoader') if defined(&boot_DynaLoader) &&
15:                                 !defined(&dl_error);
16: package XSLoader;
17: 
18: sub load {
19:     package DynaLoader;
20: 
21:     my ($caller, $modlibname) = caller();
22:     my $module = $caller;
23: 
24:     if (@_) {
25:         $module = $_[0];
26:     } else {
27:         $_[0] = $module;
28:     }
29: 
30:     # work with static linking too
31:     my $boots = "$module\::bootstrap";
32:     goto &$boots if defined &$boots;
33: 
34:     goto \&XSLoader::bootstrap_inherit unless $module and defined &dl_load_file;
35: 
36:     my @modparts = split(/::/,$module);
37:     my $modfname = $modparts[-1];
38: 
39:     my $modpname = join('/',@modparts);
40:     my $c = () = split(/::/,$caller,-1);
41:     $modlibname =~ s,[\\/][^\\/]+$,, while $c--;    # Q&D basename
42:     # Does this look like a relative path?
43:     if ($modlibname !~ m{^/}) {
44:         # Someone may have a #line directive that changes the file name, or
45:         # may be calling XSLoader::load from inside a string eval.  We cer-
46:         # tainly do not want to go loading some code that is not in @INC,
47:         # as it could be untrusted.
48:         #
49:         # We could just fall back to DynaLoader here, but then the rest of
50:         # this function would go untested in the perl core, since all @INC
51:         # paths are relative during testing.  That would be a time bomb
52:         # waiting to happen, since bugs could be introduced into the code.
53:         #
54:         # So look through @INC to see if $modlibname is in it.  A rela-
55:         # tive $modlibname is not a common occurrence, so this block is
56:         # not hot code.
57:         FOUND: {
58:             for (@INC) {
59:                 if ($_ eq $modlibname) {
60:                     last FOUND;
61:                 }
62:             }
63:             # Not found.  Fall back to DynaLoader.
64:             goto \&XSLoader::bootstrap_inherit;
65:         }
66:     }
67:     my $file = "$modlibname/auto/$modpname/$modfname.so";
68: 
69: #   print STDERR "XSLoader::load for $module ($file)\n" if $dl_debug;
70: 
71:     my $bs = $file;
72:     $bs =~ s/(\.\w+)?(;\d*)?$/\.bs/; # look for .bs 'beside' the library
73: 
74:     if (-s $bs) { # only read file if it's not empty
75: #       print STDERR "BS: $bs ($^O, $dlsrc)\n" if $dl_debug;
76:         eval { do $bs; };
77:         warn "$bs: $@\n" if $@;
78: 	goto \&XSLoader::bootstrap_inherit;
79:     }
80: 
81:     goto \&XSLoader::bootstrap_inherit if not -f $file;
82: 
83:     my $bootname = "boot_$module";
84:     $bootname =~ s/\W/_/g;
85:     @DynaLoader::dl_require_symbols = ($bootname);
86: 
87:     my $boot_symbol_ref;
88: 
89:     # Many dynamic extension loading problems will appear to come from
90:     # this section of code: XYZ failed at line 123 of DynaLoader.pm.
91:     # Often these errors are actually occurring in the initialisation
92:     # C code of the extension XS file. Perl reports the error as being
93:     # in this perl code simply because this was the last perl code
94:     # it executed.
95: 
96:     my $libref = dl_load_file($file, 0) or do { 
97:         require Carp;
98:         Carp::croak("Can't load '$file' for module $module: " . dl_error());
99:     };
100:     push(@DynaLoader::dl_librefs,$libref);  # record loaded object
101: 
102:     $boot_symbol_ref = dl_find_symbol($libref, $bootname) or do {
103:         require Carp;
104:         Carp::croak("Can't find '$bootname' symbol in $file\n");
105:     };
106: 
107:     push(@DynaLoader::dl_modules, $module); # record loaded module
108: 
109:   boot:
110:     my $xs = dl_install_xsub($boots, $boot_symbol_ref, $file);
111: 
112:     # See comment block above
113:     push(@DynaLoader::dl_shared_objects, $file); # record files loaded
114:     return &$xs(@_);
115: }
116: 
117: sub bootstrap_inherit {
118:     require DynaLoader;
119:     goto \&DynaLoader::bootstrap_inherit;
120: }
121: 
122: 1;
123: 
124: 
125: __END__
126: 
127: =head1 NAME
128: 
129: XSLoader - Dynamically load C libraries into Perl code
130: 
131: =head1 VERSION
132: 
133: Version 0.24
134: 
135: =head1 SYNOPSIS
136: 
137:     package YourPackage;
138:     require XSLoader;
139: 
140:     XSLoader::load();
141: 
142: =head1 DESCRIPTION
143: 
144: This module defines a standard I<simplified> interface to the dynamic
145: linking mechanisms available on many platforms.  Its primary purpose is
146: to implement cheap automatic dynamic loading of Perl modules.
147: 
148: For a more complicated interface, see L<DynaLoader>.  Many (most)
149: features of C<DynaLoader> are not implemented in C<XSLoader>, like for
150: example the C<dl_load_flags>, not honored by C<XSLoader>.
151: 
152: =head2 Migration from C<DynaLoader>
153: 
154: A typical module using L<DynaLoader|DynaLoader> starts like this:
155: 
156:     package YourPackage;
157:     require DynaLoader;
158: 
159:     our @ISA = qw( OnePackage OtherPackage DynaLoader );
160:     our $VERSION = '0.01';
161:     bootstrap YourPackage $VERSION;
162: 
163: Change this to
164: 
165:     package YourPackage;
166:     use XSLoader;
167: 
168:     our @ISA = qw( OnePackage OtherPackage );
169:     our $VERSION = '0.01';
170:     XSLoader::load 'YourPackage', $VERSION;
171: 
172: In other words: replace C<require DynaLoader> by C<use XSLoader>, remove
173: C<DynaLoader> from C<@ISA>, change C<bootstrap> by C<XSLoader::load>.  Do not
174: forget to quote the name of your package on the C<XSLoader::load> line,
175: and add comma (C<,>) before the arguments (C<$VERSION> above).
176: 
177: Of course, if C<@ISA> contained only C<DynaLoader>, there is no need to have
178: the C<@ISA> assignment at all; moreover, if instead of C<our> one uses the
179: more backward-compatible
180: 
181:     use vars qw($VERSION @ISA);
182: 
183: one can remove this reference to C<@ISA> together with the C<@ISA> assignment.
184: 
185: If no C<$VERSION> was specified on the C<bootstrap> line, the last line becomes
186: 
187:     XSLoader::load 'YourPackage';
188: 
189: If the call to C<load> is from C<YourPackage>, then that can be further
190: simplified to
191: 
192:     XSLoader::load();
193: 
194: as C<load> will use C<caller> to determine the package.
195: 
196: =head2 Backward compatible boilerplate
197: 
198: If you want to have your cake and eat it too, you need a more complicated
199: boilerplate.
200: 
201:     package YourPackage;
202:     use vars qw($VERSION @ISA);
203: 
204:     @ISA = qw( OnePackage OtherPackage );
205:     $VERSION = '0.01';
206:     eval {
207:        require XSLoader;
208:        XSLoader::load('YourPackage', $VERSION);
209:        1;
210:     } or do {
211:        require DynaLoader;
212:        push @ISA, 'DynaLoader';
213:        bootstrap YourPackage $VERSION;
214:     };
215: 
216: The parentheses about C<XSLoader::load()> arguments are needed since we replaced
217: C<use XSLoader> by C<require>, so the compiler does not know that a function
218: C<XSLoader::load()> is present.
219: 
220: This boilerplate uses the low-overhead C<XSLoader> if present; if used with
221: an antique Perl which has no C<XSLoader>, it falls back to using C<DynaLoader>.
222: 
223: =head1 Order of initialization: early load()
224: 
225: I<Skip this section if the XSUB functions are supposed to be called from other
226: modules only; read it only if you call your XSUBs from the code in your module,
227: or have a C<BOOT:> section in your XS file (see L<perlxs/"The BOOT: Keyword">).
228: What is described here is equally applicable to the L<DynaLoader|DynaLoader>
229: interface.>
230: 
231: A sufficiently complicated module using XS would have both Perl code (defined
232: in F<YourPackage.pm>) and XS code (defined in F<YourPackage.xs>).  If this
233: Perl code makes calls into this XS code, and/or this XS code makes calls to
234: the Perl code, one should be careful with the order of initialization.
235: 
236: The call to C<XSLoader::load()> (or C<bootstrap()>) calls the module's
237: bootstrap code. For modules build by F<xsubpp> (nearly all modules) this
238: has three side effects:
239: 
240: =over
241: 
242: =item *
243: 
244: A sanity check is done to ensure that the versions of the F<.pm> and the
245: (compiled) F<.xs> parts are compatible. If C<$VERSION> was specified, this
246: is used for the check. If not specified, it defaults to
247: C<$XS_VERSION // $VERSION> (in the module's namespace)
248: 
249: =item *
250: 
251: the XSUBs are made accessible from Perl
252: 
253: =item *
254: 
255: if a C<BOOT:> section was present in the F<.xs> file, the code there is called.
256: 
257: =back
258: 
259: Consequently, if the code in the F<.pm> file makes calls to these XSUBs, it is
260: convenient to have XSUBs installed before the Perl code is defined; for
261: example, this makes prototypes for XSUBs visible to this Perl code.
262: Alternatively, if the C<BOOT:> section makes calls to Perl functions (or
263: uses Perl variables) defined in the F<.pm> file, they must be defined prior to
264: the call to C<XSLoader::load()> (or C<bootstrap()>).
265: 
266: The first situation being much more frequent, it makes sense to rewrite the
267: boilerplate as
268: 
269:     package YourPackage;
270:     use XSLoader;
271:     use vars qw($VERSION @ISA);
272: 
273:     BEGIN {
274:        @ISA = qw( OnePackage OtherPackage );
275:        $VERSION = '0.01';
276: 
277:        # Put Perl code used in the BOOT: section here
278: 
279:        XSLoader::load 'YourPackage', $VERSION;
280:     }
281: 
282:     # Put Perl code making calls into XSUBs here
283: 
284: =head2 The most hairy case
285: 
286: If the interdependence of your C<BOOT:> section and Perl code is
287: more complicated than this (e.g., the C<BOOT:> section makes calls to Perl
288: functions which make calls to XSUBs with prototypes), get rid of the C<BOOT:>
289: section altogether.  Replace it with a function C<onBOOT()>, and call it like
290: this:
291: 
292:     package YourPackage;
293:     use XSLoader;
294:     use vars qw($VERSION @ISA);
295: 
296:     BEGIN {
297:        @ISA = qw( OnePackage OtherPackage );
298:        $VERSION = '0.01';
299:        XSLoader::load 'YourPackage', $VERSION;
300:     }
301: 
302:     # Put Perl code used in onBOOT() function here; calls to XSUBs are
303:     # prototype-checked.
304: 
305:     onBOOT;
306: 
307:     # Put Perl initialization code assuming that XS is initialized here
308: 
309: 
310: =head1 DIAGNOSTICS
311: 
312: =over
313: 
314: =item C<Can't find '%s' symbol in %s>
315: 
316: B<(F)> The bootstrap symbol could not be found in the extension module.
317: 
318: =item C<Can't load '%s' for module %s: %s>
319: 
320: B<(F)> The loading or initialisation of the extension module failed.
321: The detailed error follows.
322: 
323: =item C<Undefined symbols present after loading %s: %s>
324: 
325: B<(W)> As the message says, some symbols stay undefined although the
326: extension module was correctly loaded and initialised. The list of undefined
327: symbols follows.
328: 
329: =back
330: 
331: =head1 LIMITATIONS
332: 
333: To reduce the overhead as much as possible, only one possible location
334: is checked to find the extension DLL (this location is where C<make install>
335: would put the DLL).  If not found, the search for the DLL is transparently
336: delegated to C<DynaLoader>, which looks for the DLL along the C<@INC> list.
337: 
338: In particular, this is applicable to the structure of C<@INC> used for testing
339: not-yet-installed extensions.  This means that running uninstalled extensions
340: may have much more overhead than running the same extensions after
341: C<make install>.
342: 
343: 
344: =head1 KNOWN BUGS
345: 
346: The new simpler way to call C<XSLoader::load()> with no arguments at all
347: does not work on Perl 5.8.4 and 5.8.5.
348: 
349: 
350: =head1 BUGS
351: 
352: Please report any bugs or feature requests via the perlbug(1) utility.
353: 
354: 
355: =head1 SEE ALSO
356: 
357: L<DynaLoader>
358: 
359: 
360: =head1 AUTHORS
361: 
362: Ilya Zakharevich originally extracted C<XSLoader> from C<DynaLoader>.
363: 
364: CPAN version is currently maintained by SE<eacute>bastien Aperghis-Tramoni
365: E<lt>sebastien@aperghis.netE<gt>.
366: 
367: Previous maintainer was Michael G Schwern <schwern@pobox.com>.
368: 
369: 
370: =head1 COPYRIGHT & LICENSE
371: 
372: Copyright (C) 1990-2011 by Larry Wall and others.
373: 
374: This program is free software; you can redistribute it and/or modify
375: it under the same terms as Perl itself.
376: 
377: =cut