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
122 goto &DynaLoader::bootstrap_inherit;
131 XSLoader - Dynamically load C libraries into Perl code
138 XSLoader::load 'YourPackage', $YourPackage::VERSION;
142 This module defines a standard I<simplified> interface to the dynamic
143 linking mechanisms available on many platforms. Its primary purpose is
144 to implement cheap automatic dynamic loading of Perl modules.
146 For a more complicated interface, see L<DynaLoader>. Many (most)
147 features of DynaLoader are not implemented in XSLoader, like for
148 example the dl_load_flags, not honored by XSLoader.
150 =head2 Migration from C<DynaLoader>
152 A typical module using L<DynaLoader|DynaLoader> starts like this:
157 our @ISA = qw( OnePackage OtherPackage DynaLoader );
158 our $VERSION = '0.01';
159 bootstrap YourPackage $VERSION;
166 our @ISA = qw( OnePackage OtherPackage );
167 our $VERSION = '0.01';
168 XSLoader::load 'YourPackage', $VERSION;
170 In other words: replace C<require DynaLoader> by C<use XSLoader>, remove
171 C<DynaLoader> from @ISA, change C<bootstrap> by C<XSLoader::load>. Do not
172 forget to quote the name of your package on the C<XSLoader::load> line,
173 and add comma (C<,>) before the arguments ($VERSION above).
175 Of course, if @ISA contained only C<DynaLoader>, there is no need to have the
176 @ISA assignment at all; moreover, if instead of C<our> one uses the more
179 use vars qw($VERSION @ISA);
181 one can remove this reference to @ISA together with the @ISA assignment.
183 If no $VERSION was specified on the C<bootstrap> line, the last line becomes
185 XSLoader::load 'YourPackage';
187 =head2 Backward compatible boilerplate
189 If you want to have your cake and eat it too, you need a more complicated
193 use vars qw($VERSION @ISA);
195 @ISA = qw( OnePackage OtherPackage );
199 XSLoader::load('YourPackage', $VERSION);
203 push @ISA, 'DynaLoader';
204 bootstrap YourPackage $VERSION;
207 The parentheses about XSLoader::load() arguments are needed since we replaced
208 C<use XSLoader> by C<require>, so the compiler does not know that a function
209 XSLoader::load() is present.
211 This boilerplate uses the low-overhead C<XSLoader> if present; if used with
212 an antic Perl which has no C<XSLoader>, it falls back to using C<DynaLoader>.
214 =head1 Order of initialization: early load()
216 I<Skip this section if the XSUB functions are supposed to be called from other
217 modules only; read it only if you call your XSUBs from the code in your module,
218 or have a C<BOOT:> section in your XS file (see L<perlxs/"The BOOT: Keyword">).
219 What is described here is equally applicable to the L<DynaLoader|DynaLoader>
222 A sufficiently complicated module using XS would have both Perl code (defined
223 in F<YourPackage.pm>) and XS code (defined in F<YourPackage.xs>). If this
224 Perl code makes calls into this XS code, and/or this XS code makes calls to
225 the Perl code, one should be careful with the order of initialization.
227 The call to XSLoader::load() (or bootstrap()) has three side effects:
233 if $VERSION was specified, a sanity check is done to ensure that the versions
234 of the F<.pm> and the (compiled) F<.xs> parts are compatible;
238 the XSUBs are made accessible from Perl;
242 if a C<BOOT:> section was present in the F<.xs> file, the code there is called.
246 Consequently, if the code in the F<.pm> file makes calls to these XSUBs, it is
247 convenient to have XSUBs installed before the Perl code is defined; for
248 example, this makes prototypes for XSUBs visible to this Perl code.
249 Alternatively, if the C<BOOT:> section makes calls to Perl functions (or
250 uses Perl variables) defined in the F<.pm> file, they must be defined prior to
251 the call to XSLoader::load() (or bootstrap()).
253 The first situation being much more frequent, it makes sense to rewrite the
258 use vars qw($VERSION @ISA);
261 @ISA = qw( OnePackage OtherPackage );
264 # Put Perl code used in the BOOT: section here
266 XSLoader::load 'YourPackage', $VERSION;
269 # Put Perl code making calls into XSUBs here
271 =head2 The most hairy case
273 If the interdependence of your C<BOOT:> section and Perl code is
274 more complicated than this (e.g., the C<BOOT:> section makes calls to Perl
275 functions which make calls to XSUBs with prototypes), get rid of the C<BOOT:>
276 section altogether. Replace it with a function onBOOT(), and call it like
281 use vars qw($VERSION @ISA);
284 @ISA = qw( OnePackage OtherPackage );
286 XSLoader::load 'YourPackage', $VERSION;
289 # Put Perl code used in onBOOT() function here; calls to XSUBs are
294 # Put Perl initialization code assuming that XS is initialized here
298 To reduce the overhead as much as possible, only one possible location
299 is checked to find the extension DLL (this location is where C<make install>
300 would put the DLL). If not found, the search for the DLL is transparently
301 delegated to C<DynaLoader>, which looks for the DLL along the @INC list.
303 In particular, this is applicable to the structure of @INC used for testing
304 not-yet-installed extensions. This means that running uninstalled extensions
305 may have much more overhead than running the same extensions after
310 Ilya Zakharevich: extraction from DynaLoader.