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)
19 # enable debug/trace messages from DynaLoader perl code
20 # $dl_debug = $ENV{PERL_DL_DEBUG} || 0 unless defined $dl_debug;
24 print OUT ' my $dl_dlext = ', to_string($Config::Config{'dlext'}), ";\n" ;
30 # No prizes for guessing why we don't say 'bootstrap DynaLoader;' here.
31 # NOTE: All dl_*.xs (including dl_none.xs) define a dl_error() XSUB
32 boot_DynaLoader('DynaLoader') if defined(&boot_DynaLoader) &&
39 die q{XSLoader::load('Your::Module', $Your::Module::VERSION)} unless @_;
43 # work with static linking too
44 my $b = "$module\::bootstrap";
45 goto &$b if defined &$b;
47 goto retry unless $module and defined &dl_load_file;
49 my @modparts = split(/::/,$module);
50 my $modfname = $modparts[-1];
54 print OUT <<'EOT' if defined &DynaLoader::mod2fname;
55 # Some systems have restrictions on files names for DLL's etc.
56 # mod2fname returns appropriate file base name (typically truncated)
57 # It may also edit @modparts if required.
58 $modfname = &mod2fname(\@modparts) if defined &mod2fname;
63 my $modpname = join('/',@modparts);
64 my $modlibname = (caller())[1];
66 $modlibname =~ s,[\\/][^\\/]+$,, while $c--; # Q&D basename
67 my $file = "$modlibname/auto/$modpname/$modfname.$dl_dlext";
69 # print STDERR "XSLoader::load for $module ($file)\n" if $dl_debug;
72 $bs =~ s/(\.\w+)?(;\d*)?$/\.bs/; # look for .bs 'beside' the library
74 goto retry if not -f $file or -s $bs;
76 my $bootname = "boot_$module";
77 $bootname =~ s/\W/_/g;
78 @dl_require_symbols = ($bootname);
82 if ($^O eq 'darwin') {
83 if ($boot_symbol_ref = dl_find_symbol(0, $bootname)) {
84 goto boot; #extension library has already been loaded, e.g. darwin
88 # Many dynamic extension loading problems will appear to come from
89 # this section of code: XYZ failed at line 123 of DynaLoader.pm.
90 # Often these errors are actually occurring in the initialisation
91 # C code of the extension XS file. Perl reports the error as being
92 # in this perl code simply because this was the last perl code
95 my $libref = dl_load_file($file, 0) or do {
97 Carp::croak("Can't load '$file' for module $module: " . dl_error());
99 push(@dl_librefs,$libref); # record loaded object
101 my @unresolved = dl_undef_symbols();
104 Carp::carp("Undefined symbols present after loading $file: @unresolved\n");
107 $boot_symbol_ref = dl_find_symbol($libref, $bootname) or do {
109 Carp::croak("Can't find '$bootname' symbol in $file\n");
112 push(@dl_modules, $module); # record loaded module
115 my $xs = dl_install_xsub("${module}::bootstrap", $boot_symbol_ref, $file);
117 # See comment block above
118 push(@DynaLoader::dl_shared_objects, $file); # record files loaded
123 goto &DynaLoader::bootstrap_inherit;
132 XSLoader - Dynamically load C libraries into Perl code
139 XSLoader::load 'YourPackage', $YourPackage::VERSION;
143 This module defines a standard I<simplified> interface to the dynamic
144 linking mechanisms available on many platforms. Its primary purpose is
145 to implement cheap automatic dynamic loading of Perl modules.
147 For a more complicated interface, see L<DynaLoader>. Many (most)
148 features of DynaLoader are not implemented in XSLoader, like for
149 example the dl_load_flags, not honored by XSLoader.
151 =head2 Migration from C<DynaLoader>
153 A typical module using L<DynaLoader|DynaLoader> starts like this:
158 our @ISA = qw( OnePackage OtherPackage DynaLoader );
159 our $VERSION = '0.01';
160 bootstrap YourPackage $VERSION;
167 our @ISA = qw( OnePackage OtherPackage );
168 our $VERSION = '0.01';
169 XSLoader::load 'YourPackage', $VERSION;
171 In other words: replace C<require DynaLoader> by C<use XSLoader>, remove
172 C<DynaLoader> from @ISA, change C<bootstrap> by C<XSLoader::load>. Do not
173 forget to quote the name of your package on the C<XSLoader::load> line,
174 and add comma (C<,>) before the arguments ($VERSION above).
176 Of course, if @ISA contained only C<DynaLoader>, there is no need to have the
177 @ISA assignment at all; moreover, if instead of C<our> one uses the more
180 use vars qw($VERSION @ISA);
182 one can remove this reference to @ISA together with the @ISA assignment.
184 If no $VERSION was specified on the C<bootstrap> line, the last line becomes
186 XSLoader::load 'YourPackage';
188 =head2 Backward compatible boilerplate
190 If you want to have your cake and eat it too, you need a more complicated
194 use vars qw($VERSION @ISA);
196 @ISA = qw( OnePackage OtherPackage );
200 XSLoader::load('YourPackage', $VERSION);
204 push @ISA, 'DynaLoader';
205 bootstrap YourPackage $VERSION;
208 The parentheses about XSLoader::load() arguments are needed since we replaced
209 C<use XSLoader> by C<require>, so the compiler does not know that a function
210 XSLoader::load() is present.
212 This boilerplate uses the low-overhead C<XSLoader> if present; if used with
213 an antic Perl which has no C<XSLoader>, it falls back to using C<DynaLoader>.
215 =head1 Order of initialization: early load()
217 I<Skip this section if the XSUB functions are supposed to be called from other
218 modules only; read it only if you call your XSUBs from the code in your module,
219 or have a C<BOOT:> section in your XS file (see L<perlxs/"The BOOT: Keyword">).
220 What is described here is equally applicable to the L<DynaLoader|DynaLoader>
223 A sufficiently complicated module using XS would have both Perl code (defined
224 in F<YourPackage.pm>) and XS code (defined in F<YourPackage.xs>). If this
225 Perl code makes calls into this XS code, and/or this XS code makes calls to
226 the Perl code, one should be careful with the order of initialization.
228 The call to XSLoader::load() (or bootstrap()) has three side effects:
234 if $VERSION was specified, a sanity check is done to ensure that the versions
235 of the F<.pm> and the (compiled) F<.xs> parts are compatible;
239 the XSUBs are made accessible from Perl;
243 if a C<BOOT:> section was present in the F<.xs> file, the code there is called.
247 Consequently, if the code in the F<.pm> file makes calls to these XSUBs, it is
248 convenient to have XSUBs installed before the Perl code is defined; for
249 example, this makes prototypes for XSUBs visible to this Perl code.
250 Alternatively, if the C<BOOT:> section makes calls to Perl functions (or
251 uses Perl variables) defined in the F<.pm> file, they must be defined prior to
252 the call to XSLoader::load() (or bootstrap()).
254 The first situation being much more frequent, it makes sense to rewrite the
259 use vars qw($VERSION @ISA);
262 @ISA = qw( OnePackage OtherPackage );
265 # Put Perl code used in the BOOT: section here
267 XSLoader::load 'YourPackage', $VERSION;
270 # Put Perl code making calls into XSUBs here
272 =head2 The most hairy case
274 If the interdependence of your C<BOOT:> section and Perl code is
275 more complicated than this (e.g., the C<BOOT:> section makes calls to Perl
276 functions which make calls to XSUBs with prototypes), get rid of the C<BOOT:>
277 section altogether. Replace it with a function onBOOT(), and call it like
282 use vars qw($VERSION @ISA);
285 @ISA = qw( OnePackage OtherPackage );
287 XSLoader::load 'YourPackage', $VERSION;
290 # Put Perl code used in onBOOT() function here; calls to XSUBs are
295 # Put Perl initialization code assuming that XS is initialized here
299 To reduce the overhead as much as possible, only one possible location
300 is checked to find the extension DLL (this location is where C<make install>
301 would put the DLL). If not found, the search for the DLL is transparently
302 delegated to C<DynaLoader>, which looks for the DLL along the @INC list.
304 In particular, this is applicable to the structure of @INC used for testing
305 not-yet-installed extensions. This means that running uninstalled extensions
306 may have much more overhead than running the same extensions after
311 Ilya Zakharevich: extraction from DynaLoader.