1# Generated from XSLoader.pm.PL (resolved %Config::Config value) 2# This file is unique for every OS 3 4package XSLoader; 5 6$VERSION = "0.24"; 7 8#use strict; 9 10package DynaLoader; 11 12# No prizes for guessing why we don't say 'bootstrap DynaLoader;' here. 13# NOTE: All dl_*.xs (including dl_none.xs) define a dl_error() XSUB 14boot_DynaLoader('DynaLoader') if defined(&boot_DynaLoader) && 15 !defined(&dl_error); 16package XSLoader; 17 18sub load { 19 package DynaLoader; 20 21 my ($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.bundle"; 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 $boot_symbol_ref; 88 89 if ($boot_symbol_ref = dl_find_symbol( 0, $bootname )) { 90 goto boot; #extension library has already been loaded, e.g. darwin 91 } 92 # Many dynamic extension loading problems will appear to come from 93 # this section of code: XYZ failed at line 123 of DynaLoader.pm. 94 # Often these errors are actually occurring in the initialisation 95 # C code of the extension XS file. Perl reports the error as being 96 # in this perl code simply because this was the last perl code 97 # it executed. 98 99 my $libref = dl_load_file($file, 0) or do { 100 require Carp; 101 Carp::croak("Can't load '$file' for module $module: " . dl_error()); 102 }; 103 push(@DynaLoader::dl_librefs,$libref); # record loaded object 104 105 $boot_symbol_ref = dl_find_symbol($libref, $bootname) or do { 106 require Carp; 107 Carp::croak("Can't find '$bootname' symbol in $file\n"); 108 }; 109 110 push(@DynaLoader::dl_modules, $module); # record loaded module 111 112 boot: 113 my $xs = dl_install_xsub($boots, $boot_symbol_ref, $file); 114 115 # See comment block above 116 push(@DynaLoader::dl_shared_objects, $file); # record files loaded 117 return &$xs(@_); 118} 119 120sub bootstrap_inherit { 121 require DynaLoader; 122 goto \&DynaLoader::bootstrap_inherit; 123} 124 1251; 126 127 128__END__ 129 130=head1 NAME 131 132XSLoader - Dynamically load C libraries into Perl code 133 134=head1 VERSION 135 136Version 0.24 137 138=head1 SYNOPSIS 139 140 package YourPackage; 141 require XSLoader; 142 143 XSLoader::load(); 144 145=head1 DESCRIPTION 146 147This module defines a standard I<simplified> interface to the dynamic 148linking mechanisms available on many platforms. Its primary purpose is 149to implement cheap automatic dynamic loading of Perl modules. 150 151For a more complicated interface, see L<DynaLoader>. Many (most) 152features of C<DynaLoader> are not implemented in C<XSLoader>, like for 153example the C<dl_load_flags>, not honored by C<XSLoader>. 154 155=head2 Migration from C<DynaLoader> 156 157A typical module using L<DynaLoader|DynaLoader> starts like this: 158 159 package YourPackage; 160 require DynaLoader; 161 162 our @ISA = qw( OnePackage OtherPackage DynaLoader ); 163 our $VERSION = '0.01'; 164 bootstrap YourPackage $VERSION; 165 166Change this to 167 168 package YourPackage; 169 use XSLoader; 170 171 our @ISA = qw( OnePackage OtherPackage ); 172 our $VERSION = '0.01'; 173 XSLoader::load 'YourPackage', $VERSION; 174 175In other words: replace C<require DynaLoader> by C<use XSLoader>, remove 176C<DynaLoader> from C<@ISA>, change C<bootstrap> by C<XSLoader::load>. Do not 177forget to quote the name of your package on the C<XSLoader::load> line, 178and add comma (C<,>) before the arguments (C<$VERSION> above). 179 180Of course, if C<@ISA> contained only C<DynaLoader>, there is no need to have 181the C<@ISA> assignment at all; moreover, if instead of C<our> one uses the 182more backward-compatible 183 184 use vars qw($VERSION @ISA); 185 186one can remove this reference to C<@ISA> together with the C<@ISA> assignment. 187 188If no C<$VERSION> was specified on the C<bootstrap> line, the last line becomes 189 190 XSLoader::load 'YourPackage'; 191 192If the call to C<load> is from C<YourPackage>, then that can be further 193simplified to 194 195 XSLoader::load(); 196 197as C<load> will use C<caller> to determine the package. 198 199=head2 Backward compatible boilerplate 200 201If you want to have your cake and eat it too, you need a more complicated 202boilerplate. 203 204 package YourPackage; 205 use vars qw($VERSION @ISA); 206 207 @ISA = qw( OnePackage OtherPackage ); 208 $VERSION = '0.01'; 209 eval { 210 require XSLoader; 211 XSLoader::load('YourPackage', $VERSION); 212 1; 213 } or do { 214 require DynaLoader; 215 push @ISA, 'DynaLoader'; 216 bootstrap YourPackage $VERSION; 217 }; 218 219The parentheses about C<XSLoader::load()> arguments are needed since we replaced 220C<use XSLoader> by C<require>, so the compiler does not know that a function 221C<XSLoader::load()> is present. 222 223This boilerplate uses the low-overhead C<XSLoader> if present; if used with 224an antique Perl which has no C<XSLoader>, it falls back to using C<DynaLoader>. 225 226=head1 Order of initialization: early load() 227 228I<Skip this section if the XSUB functions are supposed to be called from other 229modules only; read it only if you call your XSUBs from the code in your module, 230or have a C<BOOT:> section in your XS file (see L<perlxs/"The BOOT: Keyword">). 231What is described here is equally applicable to the L<DynaLoader|DynaLoader> 232interface.> 233 234A sufficiently complicated module using XS would have both Perl code (defined 235in F<YourPackage.pm>) and XS code (defined in F<YourPackage.xs>). If this 236Perl code makes calls into this XS code, and/or this XS code makes calls to 237the Perl code, one should be careful with the order of initialization. 238 239The call to C<XSLoader::load()> (or C<bootstrap()>) calls the module's 240bootstrap code. For modules build by F<xsubpp> (nearly all modules) this 241has three side effects: 242 243=over 244 245=item * 246 247A sanity check is done to ensure that the versions of the F<.pm> and the 248(compiled) F<.xs> parts are compatible. If C<$VERSION> was specified, this 249is used for the check. If not specified, it defaults to 250C<$XS_VERSION // $VERSION> (in the module's namespace) 251 252=item * 253 254the XSUBs are made accessible from Perl 255 256=item * 257 258if a C<BOOT:> section was present in the F<.xs> file, the code there is called. 259 260=back 261 262Consequently, if the code in the F<.pm> file makes calls to these XSUBs, it is 263convenient to have XSUBs installed before the Perl code is defined; for 264example, this makes prototypes for XSUBs visible to this Perl code. 265Alternatively, if the C<BOOT:> section makes calls to Perl functions (or 266uses Perl variables) defined in the F<.pm> file, they must be defined prior to 267the call to C<XSLoader::load()> (or C<bootstrap()>). 268 269The first situation being much more frequent, it makes sense to rewrite the 270boilerplate as 271 272 package YourPackage; 273 use XSLoader; 274 use vars qw($VERSION @ISA); 275 276 BEGIN { 277 @ISA = qw( OnePackage OtherPackage ); 278 $VERSION = '0.01'; 279 280 # Put Perl code used in the BOOT: section here 281 282 XSLoader::load 'YourPackage', $VERSION; 283 } 284 285 # Put Perl code making calls into XSUBs here 286 287=head2 The most hairy case 288 289If the interdependence of your C<BOOT:> section and Perl code is 290more complicated than this (e.g., the C<BOOT:> section makes calls to Perl 291functions which make calls to XSUBs with prototypes), get rid of the C<BOOT:> 292section altogether. Replace it with a function C<onBOOT()>, and call it like 293this: 294 295 package YourPackage; 296 use XSLoader; 297 use vars qw($VERSION @ISA); 298 299 BEGIN { 300 @ISA = qw( OnePackage OtherPackage ); 301 $VERSION = '0.01'; 302 XSLoader::load 'YourPackage', $VERSION; 303 } 304 305 # Put Perl code used in onBOOT() function here; calls to XSUBs are 306 # prototype-checked. 307 308 onBOOT; 309 310 # Put Perl initialization code assuming that XS is initialized here 311 312 313=head1 DIAGNOSTICS 314 315=over 316 317=item C<Can't find '%s' symbol in %s> 318 319B<(F)> The bootstrap symbol could not be found in the extension module. 320 321=item C<Can't load '%s' for module %s: %s> 322 323B<(F)> The loading or initialisation of the extension module failed. 324The detailed error follows. 325 326=item C<Undefined symbols present after loading %s: %s> 327 328B<(W)> As the message says, some symbols stay undefined although the 329extension module was correctly loaded and initialised. The list of undefined 330symbols follows. 331 332=back 333 334=head1 LIMITATIONS 335 336To reduce the overhead as much as possible, only one possible location 337is checked to find the extension DLL (this location is where C<make install> 338would put the DLL). If not found, the search for the DLL is transparently 339delegated to C<DynaLoader>, which looks for the DLL along the C<@INC> list. 340 341In particular, this is applicable to the structure of C<@INC> used for testing 342not-yet-installed extensions. This means that running uninstalled extensions 343may have much more overhead than running the same extensions after 344C<make install>. 345 346 347=head1 KNOWN BUGS 348 349The new simpler way to call C<XSLoader::load()> with no arguments at all 350does not work on Perl 5.8.4 and 5.8.5. 351 352 353=head1 BUGS 354 355Please report any bugs or feature requests via the perlbug(1) utility. 356 357 358=head1 SEE ALSO 359 360L<DynaLoader> 361 362 363=head1 AUTHORS 364 365Ilya Zakharevich originally extracted C<XSLoader> from C<DynaLoader>. 366 367CPAN version is currently maintained by SE<eacute>bastien Aperghis-Tramoni 368E<lt>sebastien@aperghis.netE<gt>. 369 370Previous maintainer was Michael G Schwern <schwern@pobox.com>. 371 372 373=head1 COPYRIGHT & LICENSE 374 375Copyright (C) 1990-2011 by Larry Wall and others. 376 377This program is free software; you can redistribute it and/or modify 378it under the same terms as Perl itself. 379 380=cut 381