10 unlink "XSLoader.pm" if -f "XSLoader.pm";
11 open OUT, ">XSLoader.pm" or die $!;
13 # Generated from XSLoader.pm.PL (resolved %Config::Config value)
17 # And Gandalf said: 'Many folk like to know beforehand what is to
18 # be set on the table; but those who have laboured to prepare the
19 # feast like to keep their secret; for wonder makes the words of
22 # (Quote from Tolkien sugested by Anno Siegel.)
24 # See pod text at end of file for documentation.
25 # See also ext/DynaLoader/README in source tree for other information.
27 # Tim.Bunce@ig.co.uk, August 1994
29 $VERSION = "0.01"; # avoid typo warning
31 # enable debug/trace messages from DynaLoader perl code
32 # $dl_debug = $ENV{PERL_DL_DEBUG} || 0 unless defined $dl_debug;
36 print OUT ' my $dl_dlext = ', to_string($Config::Config{'dlext'}), ";\n" ;
42 # No prizes for guessing why we don't say 'bootstrap DynaLoader;' here.
43 # NOTE: All dl_*.xs (including dl_none.xs) define a dl_error() XSUB
44 boot_DynaLoader('DynaLoader') if defined(&boot_DynaLoader) &&
50 # The bootstrap function cannot be autoloaded (without complications)
51 # so we define it here:
58 # work with static linking too
59 my $b = "$module\::bootstrap";
60 goto &$b if defined &$b;
62 goto retry unless $module and defined &dl_load_file;
64 my @modparts = split(/::/,$module);
65 my $modfname = $modparts[-1];
69 print OUT <<'EOT' if defined &DynaLoader::mod2fname;
70 # Some systems have restrictions on files names for DLL's etc.
71 # mod2fname returns appropriate file base name (typically truncated)
72 # It may also edit @modparts if required.
73 $modfname = &mod2fname(\@modparts) if defined &mod2fname;
78 my $modpname = join('/',@modparts);
79 my $modlibname = (caller())[1];
81 $modlibname =~ s,[\\/][^\\/]+$,, while $c--; # Q&D basename
82 my $file = "$modlibname/auto/$modpname/$modfname.$dl_dlext";
84 # print STDERR "XSLoader::load for $module ($file)\n" if $dl_debug;
87 $bs =~ s/(\.\w+)?(;\d*)?$/\.bs/; # look for .bs 'beside' the library
89 goto retry if not -f $file or -s $bs;
91 my $bootname = "boot_$module";
92 $bootname =~ s/\W/_/g;
93 @dl_require_symbols = ($bootname);
97 if ($^O eq 'darwin') {
98 if ($boot_symbol_ref = dl_find_symbol(0, $bootname)) {
99 goto boot; #extension library has already been loaded, e.g. darwin
103 # Many dynamic extension loading problems will appear to come from
104 # this section of code: XYZ failed at line 123 of DynaLoader.pm.
105 # Often these errors are actually occurring in the initialisation
106 # C code of the extension XS file. Perl reports the error as being
107 # in this perl code simply because this was the last perl code
110 my $libref = dl_load_file($file, 0) or do {
112 Carp::croak("Can't load '$file' for module $module: " . dl_error());
114 push(@dl_librefs,$libref); # record loaded object
116 my @unresolved = dl_undef_symbols();
119 Carp::carp("Undefined symbols present after loading $file: @unresolved\n");
122 $boot_symbol_ref = dl_find_symbol($libref, $bootname) or do {
124 Carp::croak("Can't find '$bootname' symbol in $file\n");
127 push(@dl_modules, $module); # record loaded module
130 my $xs = dl_install_xsub("${module}::bootstrap", $boot_symbol_ref, $file);
132 # See comment block above
137 goto &DynaLoader::bootstrap_inherit;
144 XSLoader - Dynamically load C libraries into Perl code
151 XSLoader::load 'YourPackage', @args;
155 This module defines a standard I<simplified> interface to the dynamic
156 linking mechanisms available on many platforms. Its primary purpose is
157 to implement cheap automatic dynamic loading of Perl modules.
159 For more complicated interface see L<DynaLoader>. Many (most)
160 features of DynaLoader are not implemented in XSLoader, like for
161 example the dl_load_flags is not honored by XSLoader.
163 =head2 Migration from C<DynaLoader>
165 A typical module using L<DynaLoader|DynaLoader> starts like this:
170 our @ISA = qw( OnePackage OtherPackage DynaLoader );
171 our $VERSION = '0.01';
172 bootstrap YourPackage $VERSION;
179 our @ISA = qw( OnePackage OtherPackage );
180 our $VERSION = '0.01';
181 XSLoader::load 'YourPackage', $VERSION;
183 In other words: replace C<require DynaLoader> by C<use XSLoader>, remove
184 C<DynaLoader> from @ISA, change C<bootstrap> by C<XSLoader::load>. Do not
185 forget to quote the name of your package on the C<XSLoader::load> line,
186 and add comma (C<,>) before the arguments ($VERSION above).
188 Of course, if @ISA contained only C<DynaLoader>, there is no need to have the
189 @ISA assignment at all; moreover, if instead of C<our> one uses
192 use vars qw($VERSION @ISA);
194 one can remove this reference to @ISA together with the @ISA assignment
196 If no $VERSION was specified on the C<bootstrap> line, the last line becomes
198 XSLoader::load 'YourPackage';
200 =head2 Backward compatible boilerplate
202 If you want to have your cake and eat it too, you need a more complicated
206 use vars qw($VERSION @ISA);
208 @ISA = qw( OnePackage OtherPackage );
212 XSLoader::load('YourPackage', $VERSION);
216 push @ISA, 'DynaLoader';
217 bootstrap YourPackage $VERSION;
220 The parentheses about XSLoader::load() arguments are needed since we replaced
221 C<use XSLoader> by C<require>, so the compiler does not know that a function
222 XSLoader::load() is present.
224 This boilerplate uses the low-overhead C<XSLoader> if present; if used with
225 an antic Perl which has no C<XSLoader>, it falls back to using C<DynaLoader>.
227 =head1 Order of initialization: early load()
229 I<Skip this section if the XSUB functions are supposed to be called from other
230 modules only; read it only if you call your XSUBs from the code in your module,
231 or have a C<BOOT:> section in your XS file (see L<perlxs/"The BOOT: Keyword">).
232 What is described here is equally applicable to L<DynaLoader|DynaLoader>
235 A sufficiently complicated module using XS would have both Perl code (defined
236 in F<YourPackage.pm>) and XS code (defined in F<YourPackage.xs>). If this
237 Perl code makes calls into this XS code, and/or this XS code makes calls to
238 the Perl code, one should be careful with the order of initialization.
240 The call to XSLoader::load() (or bootstrap()) has three side effects:
246 if $VERSION was specified, a sanity check is done to insure that the versions
247 of the F<.pm> and the (compiled) F<.xs> parts are compatible;
251 The XSUBs are made accessible from Perl;
255 If the C<BOOT:> section was present in F<.xs> file, the code there is called.
259 Consequently, if the code in F<.pm> file makes calls to these XSUBs, it is
260 convenient to have XSUBs installed before the Perl code is defined; for
261 example, this makes prototypes for XSUBs visible to this Perl code.
262 Alternatively, if the C<BOOT:> section makes calls to Perl functions (or
263 uses Perl variables) defined in F<.pm> file, they must be defined prior to
264 the call to XSLoader::load() (or bootstrap()).
266 The first situation being much more frequent, it makes sense to rewrite the
271 use vars qw($VERSION @ISA);
274 @ISA = qw( OnePackage OtherPackage );
277 # Put Perl code used in the BOOT: section here
279 XSLoader::load 'YourPackage', $VERSION;
282 # Put Perl code making calls into XSUBs here
284 =head2 The most hairy case
286 If the interdependence of your C<BOOT:> section and Perl code is
287 more complicated than this (e.g., the C<BOOT:> section makes calls to Perl
288 functions which make calls to XSUBs with prototypes), get rid of the C<BOOT:>
289 section altogether. Replace it with a function onBOOT(), and call it like
294 use vars qw($VERSION @ISA);
297 @ISA = qw( OnePackage OtherPackage );
299 XSLoader::load 'YourPackage', $VERSION;
302 # Put Perl code used in onBOOT() function here; calls to XSUBs are
307 # Put Perl initialization code assuming that XS is initialized here
311 To reduce the overhead as much as possible, only one possible location
312 is checked to find the extension DLL (this location is where C<make install>
313 would put the DLL). If not found, the search for the DLL is transparently
314 delegated to C<DynaLoader>, which looks for the DLL along the @INC list.
316 In particular, this is applicable to the structure of @INC used for testing
317 not-yet-installed extensions. This means that the overhead of running
318 uninstalled extension may be much more than running the same extension after
323 Ilya Zakharevich: extraction from DynaLoader.