Commit | Line | Data |
---|---|---|
03c9e98c GS |
1 | |
2 | use Config; | |
3 | ||
4 | sub to_string { | |
5 | my ($value) = @_; | |
146174a9 | 6 | $value =~ s/\\/\\\\/g; |
03c9e98c GS |
7 | $value =~ s/'/\\'/g; |
8 | return "'$value'"; | |
9 | } | |
10 | ||
11 | unlink "DynaLoader.pm" if -f "DynaLoader.pm"; | |
12 | open OUT, ">DynaLoader.pm" or die $!; | |
13 | print OUT <<'EOT'; | |
14 | ||
15 | # Generated from DynaLoader.pm.PL (resolved %Config::Config values) | |
16 | ||
a0d0e21e LW |
17 | package DynaLoader; |
18 | ||
8e07c86e AD |
19 | # And Gandalf said: 'Many folk like to know beforehand what is to |
20 | # be set on the table; but those who have laboured to prepare the | |
21 | # feast like to keep their secret; for wonder makes the words of | |
22 | # praise louder.' | |
23 | ||
24 | # (Quote from Tolkien sugested by Anno Siegel.) | |
25 | # | |
26 | # See pod text at end of file for documentation. | |
27 | # See also ext/DynaLoader/README in source tree for other information. | |
28 | # | |
29 | # Tim.Bunce@ig.co.uk, August 1994 | |
30 | ||
abb9e9dc | 31 | $VERSION = "1.04"; # avoid typo warning |
dc848c6f | 32 | |
dc848c6f | 33 | require AutoLoader; |
34 | *AUTOLOAD = \&AutoLoader::AUTOLOAD; | |
8e07c86e | 35 | |
fb73857a | 36 | # The following require can't be removed during maintenance |
37 | # releases, sadly, because of the risk of buggy code that does | |
38 | # require Carp; Carp::croak "..."; without brackets dying | |
39 | # if Carp hasn't been loaded in earlier compile time. :-( | |
40 | # We'll let those bugs get found on the development track. | |
41 | require Carp if $] < 5.00450; | |
42 | ||
43 | ||
8e07c86e AD |
44 | # enable debug/trace messages from DynaLoader perl code |
45 | $dl_debug = $ENV{PERL_DL_DEBUG} || 0 unless defined $dl_debug; | |
46 | ||
ff7f3c60 NIS |
47 | # |
48 | # Flags to alter dl_load_file behaviour. Assigned bits: | |
49 | # 0x01 make symbols available for linking later dl_load_file's. | |
50 | # (only known to work on Solaris 2 using dlopen(RTLD_GLOBAL)) | |
f86702cc | 51 | # (ignored under VMS; effect is built-in to image linking) |
ff7f3c60 NIS |
52 | # |
53 | # This is called as a class method $module->dl_load_flags. The | |
54 | # definition here will be inherited and result on "default" loading | |
55 | # behaviour unless a sub-class of DynaLoader defines its own version. | |
56 | # | |
57 | ||
58 | sub dl_load_flags { 0x00 } | |
59 | ||
03c9e98c GS |
60 | # ($dl_dlext, $dlsrc) |
61 | # = @Config::Config{'dlext', 'dlsrc'}; | |
62 | EOT | |
63 | ||
64 | print OUT " (\$dl_dlext, \$dlsrc) = (", | |
65 | to_string($Config::Config{'dlext'}), ",", | |
66 | to_string($Config::Config{'dlsrc'}), ")\n;" ; | |
ff7f3c60 | 67 | |
03c9e98c | 68 | print OUT <<'EOT'; |
8e07c86e AD |
69 | |
70 | # Some systems need special handling to expand file specifications | |
71 | # (VMS support by Charles Bailey <bailey@HMIVAX.HUMGEN.UPENN.EDU>) | |
72 | # See dl_expandspec() for more details. Should be harmless but | |
73 | # inefficient to define on systems that don't need it. | |
d404d5bf | 74 | $do_expand = $Is_VMS = $^O eq 'VMS'; |
146174a9 | 75 | $Is_MacOS = $^O eq 'MacOS'; |
8e07c86e AD |
76 | |
77 | @dl_require_symbols = (); # names of symbols we need | |
78 | @dl_resolve_using = (); # names of files to link with | |
79 | @dl_library_path = (); # path to look for files | |
65f19062 GS |
80 | #@dl_librefs = (); # things we have loaded |
81 | #@dl_modules = (); # Modules we have loaded | |
8e07c86e AD |
82 | |
83 | # This is a fix to support DLD's unfortunate desire to relink -lc | |
84 | @dl_resolve_using = dl_findfile('-lc') if $dlsrc eq "dl_dld.xs"; | |
85 | ||
86 | # Initialise @dl_library_path with the 'standard' library path | |
87 | # for this platform as determined by Configure | |
03c9e98c GS |
88 | |
89 | # push(@dl_library_path, split(' ', $Config::Config{'libpth'}); | |
90 | EOT | |
91 | ||
92 | print OUT "push(\@dl_library_path, split(' ', ", | |
93 | to_string($Config::Config{'libpth'}), "));\n"; | |
94 | ||
95 | print OUT <<'EOT'; | |
8e07c86e | 96 | |
5cf1d1f1 JH |
97 | # Add to @dl_library_path any extra directories we can gather |
98 | # from environment variables. | |
146174a9 CB |
99 | if ($Is_MacOS) { |
100 | push(@dl_library_path, split(/,/, $ENV{LD_LIBRARY_PATH})) | |
101 | if exists $ENV{LD_LIBRARY_PATH}; | |
102 | } else { | |
103 | push(@dl_library_path, split(/:/, $ENV{$Config::Config{ldlibpthname}})) | |
104 | if exists $Config::Config{ldlibpthname} && | |
105 | $Config::Config{ldlibpthname} ne '' && | |
106 | exists $ENV{$Config::Config{ldlibpthname}} ;; | |
107 | push(@dl_library_path, split(/:/, $ENV{$Config::Config{ldlibpthname}})) | |
108 | if exists $Config::Config{ldlibpthname} && | |
109 | $Config::Config{ldlibpthname} ne '' && | |
110 | exists $ENV{$Config::Config{ldlibpthname}} ;; | |
5cf1d1f1 | 111 | # E.g. HP-UX supports both its native SHLIB_PATH *and* LD_LIBRARY_PATH. |
8e07c86e | 112 | push(@dl_library_path, split(/:/, $ENV{LD_LIBRARY_PATH})) |
5cf1d1f1 | 113 | if exists $ENV{LD_LIBRARY_PATH}; |
146174a9 | 114 | } |
8e07c86e AD |
115 | |
116 | # No prizes for guessing why we don't say 'bootstrap DynaLoader;' here. | |
bb3913c7 JD |
117 | boot_DynaLoader('DynaLoader') if defined(&boot_DynaLoader) && |
118 | !defined(&dl_load_file); | |
8e07c86e AD |
119 | |
120 | ||
121 | if ($dl_debug) { | |
122 | print STDERR "DynaLoader.pm loaded (@INC, @dl_library_path)\n"; | |
123 | print STDERR "DynaLoader not linked into this perl\n" | |
124 | unless defined(&boot_DynaLoader); | |
125 | } | |
126 | ||
127 | 1; # End of main code | |
128 | ||
129 | ||
fb73857a | 130 | sub croak { require Carp; Carp::croak(@_) } |
131 | ||
146174a9 CB |
132 | sub bootstrap_inherit { |
133 | my $module = $_[0]; | |
134 | local *isa = *{"$module\::ISA"}; | |
135 | local @isa = (@isa, 'DynaLoader'); | |
136 | # Cannot goto due to delocalization. Will report errors on a wrong line? | |
137 | bootstrap(@_); | |
138 | } | |
139 | ||
8e07c86e AD |
140 | # The bootstrap function cannot be autoloaded (without complications) |
141 | # so we define it here: | |
142 | ||
143 | sub bootstrap { | |
144 | # use local vars to enable $module.bs script to edit values | |
145 | local(@args) = @_; | |
146 | local($module) = $args[0]; | |
147 | local(@dirs, $file); | |
148 | ||
fb73857a | 149 | unless ($module) { |
150 | require Carp; | |
151 | Carp::confess("Usage: DynaLoader::bootstrap(module)"); | |
152 | } | |
8e07c86e AD |
153 | |
154 | # A common error on platforms which don't support dynamic loading. | |
155 | # Since it's fatal and potentially confusing we give a detailed message. | |
fb73857a | 156 | croak("Can't load module $module, dynamic loading not available in this perl.\n". |
8e07c86e AD |
157 | " (You may need to build a new perl executable which either supports\n". |
158 | " dynamic loading or has the $module module statically linked into it.)\n") | |
159 | unless defined(&dl_load_file); | |
160 | ||
161 | my @modparts = split(/::/,$module); | |
162 | my $modfname = $modparts[-1]; | |
163 | ||
164 | # Some systems have restrictions on files names for DLL's etc. | |
165 | # mod2fname returns appropriate file base name (typically truncated) | |
166 | # It may also edit @modparts if required. | |
167 | $modfname = &mod2fname(\@modparts) if defined &mod2fname; | |
168 | ||
146174a9 | 169 | my $modpname = join(($Is_MacOS ? ':' : '/'),@modparts); |
8e07c86e AD |
170 | |
171 | print STDERR "DynaLoader::bootstrap for $module ", | |
146174a9 CB |
172 | ($Is_MacOS |
173 | ? "(auto/$modpname/$modfname.$dl_dlext)\n" : | |
174 | "(:auto:$modpname:$modfname.$dl_dlext)\n") | |
175 | if $dl_debug; | |
8e07c86e AD |
176 | |
177 | foreach (@INC) { | |
54d6a3b3 | 178 | chop($_ = VMS::Filespec::unixpath($_)) if $Is_VMS; |
146174a9 CB |
179 | my $dir; |
180 | if ($Is_MacOS) { | |
181 | chop $_ if /:$/; | |
182 | $dir = "$_:auto:$modpname"; | |
183 | } else { | |
184 | $dir = "$_/auto/$modpname"; | |
185 | } | |
8e07c86e AD |
186 | next unless -d $dir; # skip over uninteresting directories |
187 | ||
188 | # check for common cases to avoid autoload of dl_findfile | |
146174a9 | 189 | my $try = $Is_MacOS ? "$dir:$modfname.$dl_dlext" : "$dir/$modfname.$dl_dlext"; |
fb73857a | 190 | last if $file = ($do_expand) ? dl_expandspec($try) : (-f $try && $try); |
8e07c86e AD |
191 | |
192 | # no luck here, save dir for possible later dl_findfile search | |
fb73857a | 193 | push @dirs, $dir; |
8e07c86e AD |
194 | } |
195 | # last resort, let dl_findfile have a go in all known locations | |
fb73857a | 196 | $file = dl_findfile(map("-L$_",@dirs,@INC), $modfname) unless $file; |
8e07c86e | 197 | |
fb73857a | 198 | croak("Can't locate loadable object for module $module in \@INC (\@INC contains: @INC)") |
199 | unless $file; # wording similar to error from 'require' | |
8e07c86e | 200 | |
b6837a3b | 201 | $file = uc($file) if $Is_VMS && $Config{d_vms_case_sensitive_symbols}; |
8e07c86e AD |
202 | my $bootname = "boot_$module"; |
203 | $bootname =~ s/\W/_/g; | |
204 | @dl_require_symbols = ($bootname); | |
205 | ||
206 | # Execute optional '.bootstrap' perl script for this module. | |
207 | # The .bs file can be used to configure @dl_resolve_using etc to | |
208 | # match the needs of the individual module on this architecture. | |
209 | my $bs = $file; | |
3f45a6dd | 210 | $bs =~ s/(\.\w+)?(;\d*)?$/\.bs/; # look for .bs 'beside' the library |
8e07c86e | 211 | if (-s $bs) { # only read file if it's not empty |
d404d5bf | 212 | print STDERR "BS: $bs ($^O, $dlsrc)\n" if $dl_debug; |
8e07c86e AD |
213 | eval { do $bs; }; |
214 | warn "$bs: $@\n" if $@; | |
215 | } | |
216 | ||
217 | # Many dynamic extension loading problems will appear to come from | |
218 | # this section of code: XYZ failed at line 123 of DynaLoader.pm. | |
219 | # Often these errors are actually occurring in the initialisation | |
220 | # C code of the extension XS file. Perl reports the error as being | |
221 | # in this perl code simply because this was the last perl code | |
222 | # it executed. | |
223 | ||
ff7f3c60 | 224 | my $libref = dl_load_file($file, $module->dl_load_flags) or |
549a6b10 | 225 | croak("Can't load '$file' for module $module: ".dl_error()); |
8e07c86e | 226 | |
ff7f3c60 NIS |
227 | push(@dl_librefs,$libref); # record loaded object |
228 | ||
8e07c86e | 229 | my @unresolved = dl_undef_symbols(); |
fb73857a | 230 | if (@unresolved) { |
231 | require Carp; | |
232 | Carp::carp("Undefined symbols present after loading $file: @unresolved\n"); | |
233 | } | |
8e07c86e AD |
234 | |
235 | my $boot_symbol_ref = dl_find_symbol($libref, $bootname) or | |
fb73857a | 236 | croak("Can't find '$bootname' symbol in $file\n"); |
8e07c86e AD |
237 | |
238 | my $xs = dl_install_xsub("${module}::bootstrap", $boot_symbol_ref, $file); | |
239 | ||
ff7f3c60 NIS |
240 | push(@dl_modules, $module); # record loaded module |
241 | ||
8e07c86e AD |
242 | # See comment block above |
243 | &$xs(@args); | |
244 | } | |
245 | ||
246 | ||
fb73857a | 247 | #sub _check_file { # private utility to handle dl_expandspec vs -f tests |
248 | # my($file) = @_; | |
249 | # return $file if (!$do_expand && -f $file); # the common case | |
250 | # return $file if ( $do_expand && ($file=dl_expandspec($file))); | |
251 | # return undef; | |
252 | #} | |
8e07c86e AD |
253 | |
254 | ||
255 | # Let autosplit and the autoloader deal with these functions: | |
256 | __END__ | |
257 | ||
258 | ||
259 | sub dl_findfile { | |
260 | # Read ext/DynaLoader/DynaLoader.doc for detailed information. | |
261 | # This function does not automatically consider the architecture | |
262 | # or the perl library auto directories. | |
263 | my (@args) = @_; | |
264 | my (@dirs, $dir); # which directories to search | |
265 | my (@found); # full paths to real files we have found | |
03c9e98c GS |
266 | EOT |
267 | ||
268 | print OUT ' my $dl_ext= ' . to_string($Config::Config{'dlext'}) . | |
269 | "; # \$Config::Config{'dlext'} suffix for perl extensions\n"; | |
270 | print OUT ' my $dl_so = ' . to_string($Config::Config{'so'}) . | |
271 | "; # \$Config::Config{'so'} suffix for shared libraries\n"; | |
272 | ||
273 | print OUT <<'EOT'; | |
8e07c86e AD |
274 | |
275 | print STDERR "dl_findfile(@args)\n" if $dl_debug; | |
276 | ||
277 | # accumulate directories but process files as they appear | |
278 | arg: foreach(@args) { | |
279 | # Special fast case: full filepath requires no search | |
54d6a3b3 | 280 | if ($Is_VMS && m%[:>/\]]% && -f $_) { |
281 | push(@found,dl_expandspec(VMS::Filespec::vmsify($_))); | |
282 | last arg unless wantarray; | |
283 | next; | |
284 | } | |
146174a9 CB |
285 | elsif ($Is_MacOS) { |
286 | if (m/:/ && -f $_) { | |
287 | push(@found,$_); | |
288 | last arg unless wantarray; | |
289 | } | |
290 | } | |
54d6a3b3 | 291 | elsif (m:/: && -f $_ && !$do_expand) { |
8e07c86e AD |
292 | push(@found,$_); |
293 | last arg unless wantarray; | |
294 | next; | |
295 | } | |
296 | ||
297 | # Deal with directories first: | |
298 | # Using a -L prefix is the preferred option (faster and more robust) | |
299 | if (m:^-L:) { s/^-L//; push(@dirs, $_); next; } | |
300 | ||
146174a9 CB |
301 | if ($Is_MacOS) { |
302 | # Otherwise we try to try to spot directories by a heuristic | |
303 | # (this is a more complicated issue than it first appears) | |
304 | if (m/:/ && -d $_) { push(@dirs, $_); next; } | |
305 | # Only files should get this far... | |
306 | my(@names, $name); # what filenames to look for | |
307 | s/^-l//; | |
308 | push(@names, $_); | |
309 | foreach $dir (@dirs, @dl_library_path) { | |
310 | next unless -d $dir; | |
311 | $dir =~ s/^([^:]+)$/:$1/; | |
312 | $dir =~ s/:$//; | |
313 | foreach $name (@names) { | |
314 | my($file) = "$dir:$name"; | |
315 | print STDERR " checking in $dir for $name\n" if $dl_debug; | |
316 | if (-f $file) { | |
317 | push(@found, $file); | |
318 | next arg; # no need to look any further | |
319 | } | |
320 | } | |
321 | } | |
322 | next; | |
323 | } | |
324 | ||
8e07c86e AD |
325 | # Otherwise we try to try to spot directories by a heuristic |
326 | # (this is a more complicated issue than it first appears) | |
327 | if (m:/: && -d $_) { push(@dirs, $_); next; } | |
328 | ||
329 | # VMS: we may be using native VMS directry syntax instead of | |
330 | # Unix emulation, so check this as well | |
54d6a3b3 | 331 | if ($Is_VMS && /[:>\]]/ && -d $_) { push(@dirs, $_); next; } |
8e07c86e AD |
332 | |
333 | # Only files should get this far... | |
334 | my(@names, $name); # what filenames to look for | |
335 | if (m:-l: ) { # convert -lname to appropriate library name | |
336 | s/-l//; | |
337 | push(@names,"lib$_.$dl_so"); | |
338 | push(@names,"lib$_.a"); | |
339 | } else { # Umm, a bare name. Try various alternatives: | |
340 | # these should be ordered with the most likely first | |
d404d5bf | 341 | push(@names,"$_.$dl_ext") unless m/\.$dl_ext$/o; |
8e07c86e AD |
342 | push(@names,"$_.$dl_so") unless m/\.$dl_so$/o; |
343 | push(@names,"lib$_.$dl_so") unless m:/:; | |
8e07c86e AD |
344 | push(@names,"$_.a") if !m/\.a$/ and $dlsrc eq "dl_dld.xs"; |
345 | push(@names, $_); | |
346 | } | |
347 | foreach $dir (@dirs, @dl_library_path) { | |
348 | next unless -d $dir; | |
54d6a3b3 | 349 | chop($dir = VMS::Filespec::unixpath($dir)) if $Is_VMS; |
8e07c86e AD |
350 | foreach $name (@names) { |
351 | my($file) = "$dir/$name"; | |
352 | print STDERR " checking in $dir for $name\n" if $dl_debug; | |
fb73857a | 353 | $file = ($do_expand) ? dl_expandspec($file) : (-f $file && $file); |
354 | #$file = _check_file($file); | |
8e07c86e AD |
355 | if ($file) { |
356 | push(@found, $file); | |
357 | next arg; # no need to look any further | |
358 | } | |
359 | } | |
360 | } | |
361 | } | |
362 | if ($dl_debug) { | |
363 | foreach(@dirs) { | |
364 | print STDERR " dl_findfile ignored non-existent directory: $_\n" unless -d $_; | |
365 | } | |
366 | print STDERR "dl_findfile found: @found\n"; | |
367 | } | |
368 | return $found[0] unless wantarray; | |
369 | @found; | |
370 | } | |
371 | ||
372 | ||
373 | sub dl_expandspec { | |
374 | my($spec) = @_; | |
375 | # Optional function invoked if DynaLoader.pm sets $do_expand. | |
376 | # Most systems do not require or use this function. | |
377 | # Some systems may implement it in the dl_*.xs file in which case | |
378 | # this autoload version will not be called but is harmless. | |
379 | ||
380 | # This function is designed to deal with systems which treat some | |
381 | # 'filenames' in a special way. For example VMS 'Logical Names' | |
382 | # (something like unix environment variables - but different). | |
383 | # This function should recognise such names and expand them into | |
384 | # full file paths. | |
385 | # Must return undef if $spec is invalid or file does not exist. | |
386 | ||
387 | my $file = $spec; # default output to input | |
388 | ||
d404d5bf | 389 | if ($Is_VMS) { # dl_expandspec should be defined in dl_vms.xs |
fb73857a | 390 | require Carp; |
4633a7c4 | 391 | Carp::croak("dl_expandspec: should be defined in XS file!\n"); |
8e07c86e AD |
392 | } else { |
393 | return undef unless -f $file; | |
394 | } | |
395 | print STDERR "dl_expandspec($spec) => $file\n" if $dl_debug; | |
396 | $file; | |
397 | } | |
398 | ||
ff7f3c60 NIS |
399 | sub dl_find_symbol_anywhere |
400 | { | |
401 | my $sym = shift; | |
402 | my $libref; | |
403 | foreach $libref (@dl_librefs) { | |
404 | my $symref = dl_find_symbol($libref,$sym); | |
405 | return $symref if $symref; | |
406 | } | |
407 | return undef; | |
408 | } | |
8e07c86e | 409 | |
3b35bae3 AD |
410 | =head1 NAME |
411 | ||
412 | DynaLoader - Dynamically load C libraries into Perl code | |
413 | ||
abb9e9dc | 414 | dl_error(), dl_findfile(), dl_expandspec(), dl_load_file(), dl_unload_file(), dl_find_symbol(), dl_find_symbol_anywhere(), dl_undef_symbols(), dl_install_xsub(), dl_load_flags(), bootstrap() - routines used by DynaLoader modules |
3b35bae3 AD |
415 | |
416 | =head1 SYNOPSIS | |
417 | ||
8e07c86e | 418 | package YourPackage; |
3b35bae3 | 419 | require DynaLoader; |
c2960299 | 420 | @ISA = qw(... DynaLoader ...); |
8e07c86e | 421 | bootstrap YourPackage; |
3b35bae3 | 422 | |
ff7f3c60 NIS |
423 | # optional method for 'global' loading |
424 | sub dl_load_flags { 0x01 } | |
425 | ||
3b35bae3 AD |
426 | |
427 | =head1 DESCRIPTION | |
428 | ||
c2960299 | 429 | This document defines a standard generic interface to the dynamic |
3b35bae3 AD |
430 | linking mechanisms available on many platforms. Its primary purpose is |
431 | to implement automatic dynamic loading of Perl modules. | |
432 | ||
c2960299 AD |
433 | This document serves as both a specification for anyone wishing to |
434 | implement the DynaLoader for a new platform and as a guide for | |
435 | anyone wishing to use the DynaLoader directly in an application. | |
436 | ||
3b35bae3 AD |
437 | The DynaLoader is designed to be a very simple high-level |
438 | interface that is sufficiently general to cover the requirements | |
439 | of SunOS, HP-UX, NeXT, Linux, VMS and other platforms. | |
440 | ||
c2960299 AD |
441 | It is also hoped that the interface will cover the needs of OS/2, NT |
442 | etc and also allow pseudo-dynamic linking (using C<ld -A> at runtime). | |
3b35bae3 AD |
443 | |
444 | It must be stressed that the DynaLoader, by itself, is practically | |
445 | useless for accessing non-Perl libraries because it provides almost no | |
446 | Perl-to-C 'glue'. There is, for example, no mechanism for calling a C | |
03c9e98c | 447 | library function or supplying arguments. A C::DynaLib module |
90248788 TB |
448 | is available from CPAN sites which performs that function for some |
449 | common system types. | |
3b35bae3 AD |
450 | |
451 | DynaLoader Interface Summary | |
452 | ||
453 | @dl_library_path | |
454 | @dl_resolve_using | |
455 | @dl_require_symbols | |
456 | $dl_debug | |
ff7f3c60 NIS |
457 | @dl_librefs |
458 | @dl_modules | |
3b35bae3 AD |
459 | Implemented in: |
460 | bootstrap($modulename) Perl | |
461 | @filepaths = dl_findfile(@names) Perl | |
ff7f3c60 NIS |
462 | $flags = $modulename->dl_load_flags Perl |
463 | $symref = dl_find_symbol_anywhere($symbol) Perl | |
3b35bae3 | 464 | |
ff7f3c60 | 465 | $libref = dl_load_file($filename, $flags) C |
abb9e9dc | 466 | $status = dl_unload_file($libref) C |
3b35bae3 AD |
467 | $symref = dl_find_symbol($libref, $symbol) C |
468 | @symbols = dl_undef_symbols() C | |
469 | dl_install_xsub($name, $symref [, $filename]) C | |
470 | $message = dl_error C | |
471 | ||
472 | =over 4 | |
473 | ||
474 | =item @dl_library_path | |
475 | ||
476 | The standard/default list of directories in which dl_findfile() will | |
477 | search for libraries etc. Directories are searched in order: | |
478 | $dl_library_path[0], [1], ... etc | |
479 | ||
480 | @dl_library_path is initialised to hold the list of 'normal' directories | |
481 | (F</usr/lib>, etc) determined by B<Configure> (C<$Config{'libpth'}>). This should | |
482 | ensure portability across a wide range of platforms. | |
483 | ||
484 | @dl_library_path should also be initialised with any other directories | |
485 | that can be determined from the environment at runtime (such as | |
486 | LD_LIBRARY_PATH for SunOS). | |
487 | ||
488 | After initialisation @dl_library_path can be manipulated by an | |
489 | application using push and unshift before calling dl_findfile(). | |
490 | Unshift can be used to add directories to the front of the search order | |
491 | either to save search time or to override libraries with the same name | |
492 | in the 'normal' directories. | |
493 | ||
494 | The load function that dl_load_file() calls may require an absolute | |
495 | pathname. The dl_findfile() function and @dl_library_path can be | |
496 | used to search for and return the absolute pathname for the | |
497 | library/object that you wish to load. | |
498 | ||
499 | =item @dl_resolve_using | |
500 | ||
501 | A list of additional libraries or other shared objects which can be | |
502 | used to resolve any undefined symbols that might be generated by a | |
503 | later call to load_file(). | |
504 | ||
505 | This is only required on some platforms which do not handle dependent | |
7a2e2cd6 | 506 | libraries automatically. For example the Socket Perl extension |
507 | library (F<auto/Socket/Socket.so>) contains references to many socket | |
508 | functions which need to be resolved when it's loaded. Most platforms | |
509 | will automatically know where to find the 'dependent' library (e.g., | |
510 | F</usr/lib/libsocket.so>). A few platforms need to be told the | |
511 | location of the dependent library explicitly. Use @dl_resolve_using | |
512 | for this. | |
3b35bae3 AD |
513 | |
514 | Example usage: | |
515 | ||
516 | @dl_resolve_using = dl_findfile('-lsocket'); | |
517 | ||
518 | =item @dl_require_symbols | |
519 | ||
520 | A list of one or more symbol names that are in the library/object file | |
521 | to be dynamically loaded. This is only required on some platforms. | |
522 | ||
ff7f3c60 NIS |
523 | =item @dl_librefs |
524 | ||
525 | An array of the handles returned by successful calls to dl_load_file(), | |
526 | made by bootstrap, in the order in which they were loaded. | |
527 | Can be used with dl_find_symbol() to look for a symbol in any of | |
528 | the loaded files. | |
529 | ||
530 | =item @dl_modules | |
531 | ||
532 | An array of module (package) names that have been bootstrap'ed. | |
533 | ||
3b35bae3 AD |
534 | =item dl_error() |
535 | ||
536 | Syntax: | |
537 | ||
538 | $message = dl_error(); | |
539 | ||
540 | Error message text from the last failed DynaLoader function. Note | |
541 | that, similar to errno in unix, a successful function call does not | |
542 | reset this message. | |
543 | ||
544 | Implementations should detect the error as soon as it occurs in any of | |
545 | the other functions and save the corresponding message for later | |
546 | retrieval. This will avoid problems on some platforms (such as SunOS) | |
547 | where the error message is very temporary (e.g., dlerror()). | |
548 | ||
549 | =item $dl_debug | |
550 | ||
551 | Internal debugging messages are enabled when $dl_debug is set true. | |
552 | Currently setting $dl_debug only affects the Perl side of the | |
553 | DynaLoader. These messages should help an application developer to | |
554 | resolve any DynaLoader usage problems. | |
555 | ||
556 | $dl_debug is set to C<$ENV{'PERL_DL_DEBUG'}> if defined. | |
557 | ||
558 | For the DynaLoader developer/porter there is a similar debugging | |
559 | variable added to the C code (see dlutils.c) and enabled if Perl was | |
560 | built with the B<-DDEBUGGING> flag. This can also be set via the | |
561 | PERL_DL_DEBUG environment variable. Set to 1 for minimal information or | |
562 | higher for more. | |
563 | ||
564 | =item dl_findfile() | |
565 | ||
566 | Syntax: | |
567 | ||
568 | @filepaths = dl_findfile(@names) | |
569 | ||
570 | Determine the full paths (including file suffix) of one or more | |
571 | loadable files given their generic names and optionally one or more | |
572 | directories. Searches directories in @dl_library_path by default and | |
573 | returns an empty list if no files were found. | |
574 | ||
575 | Names can be specified in a variety of platform independent forms. Any | |
576 | names in the form B<-lname> are converted into F<libname.*>, where F<.*> is | |
577 | an appropriate suffix for the platform. | |
578 | ||
579 | If a name does not already have a suitable prefix and/or suffix then | |
580 | the corresponding file will be searched for by trying combinations of | |
581 | prefix and suffix appropriate to the platform: "$name.o", "lib$name.*" | |
582 | and "$name". | |
583 | ||
584 | If any directories are included in @names they are searched before | |
c2960299 AD |
585 | @dl_library_path. Directories may be specified as B<-Ldir>. Any other |
586 | names are treated as filenames to be searched for. | |
3b35bae3 AD |
587 | |
588 | Using arguments of the form C<-Ldir> and C<-lname> is recommended. | |
589 | ||
590 | Example: | |
591 | ||
592 | @dl_resolve_using = dl_findfile(qw(-L/usr/5lib -lposix)); | |
593 | ||
594 | ||
595 | =item dl_expandspec() | |
596 | ||
597 | Syntax: | |
598 | ||
599 | $filepath = dl_expandspec($spec) | |
600 | ||
601 | Some unusual systems, such as VMS, require special filename handling in | |
602 | order to deal with symbolic names for files (i.e., VMS's Logical Names). | |
603 | ||
604 | To support these systems a dl_expandspec() function can be implemented | |
605 | either in the F<dl_*.xs> file or code can be added to the autoloadable | |
c2960299 AD |
606 | dl_expandspec() function in F<DynaLoader.pm>. See F<DynaLoader.pm> for |
607 | more information. | |
3b35bae3 AD |
608 | |
609 | =item dl_load_file() | |
610 | ||
611 | Syntax: | |
612 | ||
ff7f3c60 | 613 | $libref = dl_load_file($filename, $flags) |
3b35bae3 AD |
614 | |
615 | Dynamically load $filename, which must be the path to a shared object | |
616 | or library. An opaque 'library reference' is returned as a handle for | |
617 | the loaded object. Returns undef on error. | |
618 | ||
ff7f3c60 NIS |
619 | The $flags argument to alters dl_load_file behaviour. |
620 | Assigned bits: | |
621 | ||
622 | 0x01 make symbols available for linking later dl_load_file's. | |
623 | (only known to work on Solaris 2 using dlopen(RTLD_GLOBAL)) | |
f86702cc | 624 | (ignored under VMS; this is a normal part of image linking) |
ff7f3c60 | 625 | |
3b35bae3 AD |
626 | (On systems that provide a handle for the loaded object such as SunOS |
627 | and HPUX, $libref will be that handle. On other systems $libref will | |
628 | typically be $filename or a pointer to a buffer containing $filename. | |
629 | The application should not examine or alter $libref in any way.) | |
630 | ||
ff7f3c60 NIS |
631 | This is the function that does the real work. It should use the |
632 | current values of @dl_require_symbols and @dl_resolve_using if required. | |
3b35bae3 AD |
633 | |
634 | SunOS: dlopen($filename) | |
635 | HP-UX: shl_load($filename) | |
636 | Linux: dld_create_reference(@dl_require_symbols); dld_link($filename) | |
637 | NeXT: rld_load($filename, @dl_resolve_using) | |
638 | VMS: lib$find_image_symbol($filename,$dl_require_symbols[0]) | |
639 | ||
ff7f3c60 NIS |
640 | (The dlopen() function is also used by Solaris and some versions of |
641 | Linux, and is a common choice when providing a "wrapper" on other | |
642 | mechanisms as is done in the OS/2 port.) | |
643 | ||
abb9e9dc GS |
644 | =item dl_unload_file() |
645 | ||
646 | Syntax: | |
647 | ||
648 | $status = dl_unload_file($libref) | |
649 | ||
650 | Dynamically unload $libref, which must be an opaque 'library reference' as | |
651 | returned from dl_load_file. Returns one on success and zero on failure. | |
652 | ||
653 | This function is optional and may not necessarily be provided on all platforms. | |
654 | If it is defined, it is called automatically when the interpreter exits for | |
655 | every shared object or library loaded by DynaLoader::bootstrap. All such | |
656 | library references are stored in @dl_librefs by DynaLoader::Bootstrap as it | |
22851543 | 657 | loads the libraries. The files are unloaded in last-in, first-out order. |
abb9e9dc GS |
658 | |
659 | This unloading is usually necessary when embedding a shared-object perl (e.g. | |
660 | one configured with -Duseshrplib) within a larger application, and the perl | |
661 | interpreter is created and destroyed several times within the lifetime of the | |
662 | application. In this case it is possible that the system dynamic linker will | |
663 | unload and then subsequently reload the shared libperl without relocating any | |
664 | references to it from any files DynaLoaded by the previous incarnation of the | |
665 | interpreter. As a result, any shared objects opened by DynaLoader may point to | |
666 | a now invalid 'ghost' of the libperl shared object, causing apparently random | |
667 | memory corruption and crashes. This behaviour is most commonly seen when using | |
668 | Apache and mod_perl built with the APXS mechanism. | |
669 | ||
670 | SunOS: dlclose($libref) | |
671 | HP-UX: ??? | |
672 | Linux: ??? | |
673 | NeXT: ??? | |
674 | VMS: ??? | |
675 | ||
676 | (The dlclose() function is also used by Solaris and some versions of | |
677 | Linux, and is a common choice when providing a "wrapper" on other | |
678 | mechanisms as is done in the OS/2 port.) | |
679 | ||
ff7f3c60 NIS |
680 | =item dl_loadflags() |
681 | ||
682 | Syntax: | |
683 | ||
684 | $flags = dl_loadflags $modulename; | |
685 | ||
686 | Designed to be a method call, and to be overridden by a derived class | |
687 | (i.e. a class which has DynaLoader in its @ISA). The definition in | |
688 | DynaLoader itself returns 0, which produces standard behavior from | |
689 | dl_load_file(). | |
3b35bae3 AD |
690 | |
691 | =item dl_find_symbol() | |
692 | ||
693 | Syntax: | |
694 | ||
695 | $symref = dl_find_symbol($libref, $symbol) | |
696 | ||
697 | Return the address of the symbol $symbol or C<undef> if not found. If the | |
698 | target system has separate functions to search for symbols of different | |
699 | types then dl_find_symbol() should search for function symbols first and | |
700 | then other types. | |
701 | ||
702 | The exact manner in which the address is returned in $symref is not | |
703 | currently defined. The only initial requirement is that $symref can | |
704 | be passed to, and understood by, dl_install_xsub(). | |
705 | ||
706 | SunOS: dlsym($libref, $symbol) | |
707 | HP-UX: shl_findsym($libref, $symbol) | |
708 | Linux: dld_get_func($symbol) and/or dld_get_symbol($symbol) | |
709 | NeXT: rld_lookup("_$symbol") | |
710 | VMS: lib$find_image_symbol($libref,$symbol) | |
711 | ||
712 | ||
ff7f3c60 NIS |
713 | =item dl_find_symbol_anywhere() |
714 | ||
715 | Syntax: | |
716 | ||
717 | $symref = dl_find_symbol_anywhere($symbol) | |
718 | ||
719 | Applies dl_find_symbol() to the members of @dl_librefs and returns | |
720 | the first match found. | |
721 | ||
3b35bae3 AD |
722 | =item dl_undef_symbols() |
723 | ||
724 | Example | |
725 | ||
726 | @symbols = dl_undef_symbols() | |
727 | ||
728 | Return a list of symbol names which remain undefined after load_file(). | |
729 | Returns C<()> if not known. Don't worry if your platform does not provide | |
c2960299 AD |
730 | a mechanism for this. Most do not need it and hence do not provide it, |
731 | they just return an empty list. | |
3b35bae3 AD |
732 | |
733 | ||
734 | =item dl_install_xsub() | |
735 | ||
736 | Syntax: | |
737 | ||
738 | dl_install_xsub($perl_name, $symref [, $filename]) | |
739 | ||
740 | Create a new Perl external subroutine named $perl_name using $symref as | |
741 | a pointer to the function which implements the routine. This is simply | |
742 | a direct call to newXSUB(). Returns a reference to the installed | |
743 | function. | |
744 | ||
745 | The $filename parameter is used by Perl to identify the source file for | |
746 | the function if required by die(), caller() or the debugger. If | |
747 | $filename is not defined then "DynaLoader" will be used. | |
748 | ||
749 | ||
1fef88e7 | 750 | =item bootstrap() |
3b35bae3 AD |
751 | |
752 | Syntax: | |
753 | ||
754 | bootstrap($module) | |
755 | ||
756 | This is the normal entry point for automatic dynamic loading in Perl. | |
757 | ||
758 | It performs the following actions: | |
759 | ||
760 | =over 8 | |
761 | ||
762 | =item * | |
763 | ||
764 | locates an auto/$module directory by searching @INC | |
765 | ||
766 | =item * | |
767 | ||
768 | uses dl_findfile() to determine the filename to load | |
769 | ||
770 | =item * | |
771 | ||
772 | sets @dl_require_symbols to C<("boot_$module")> | |
773 | ||
774 | =item * | |
775 | ||
776 | executes an F<auto/$module/$module.bs> file if it exists | |
777 | (typically used to add to @dl_resolve_using any files which | |
778 | are required to load the module on the current platform) | |
779 | ||
780 | =item * | |
781 | ||
ff7f3c60 NIS |
782 | calls dl_load_flags() to determine how to load the file. |
783 | ||
784 | =item * | |
785 | ||
3b35bae3 AD |
786 | calls dl_load_file() to load the file |
787 | ||
788 | =item * | |
789 | ||
790 | calls dl_undef_symbols() and warns if any symbols are undefined | |
791 | ||
792 | =item * | |
793 | ||
794 | calls dl_find_symbol() for "boot_$module" | |
795 | ||
796 | =item * | |
797 | ||
798 | calls dl_install_xsub() to install it as "${module}::bootstrap" | |
799 | ||
800 | =item * | |
801 | ||
8e07c86e AD |
802 | calls &{"${module}::bootstrap"} to bootstrap the module (actually |
803 | it uses the function reference returned by dl_install_xsub for speed) | |
3b35bae3 AD |
804 | |
805 | =back | |
806 | ||
807 | =back | |
808 | ||
809 | ||
810 | =head1 AUTHOR | |
811 | ||
c2960299 AD |
812 | Tim Bunce, 11 August 1994. |
813 | ||
3b35bae3 AD |
814 | This interface is based on the work and comments of (in no particular |
815 | order): Larry Wall, Robert Sanders, Dean Roehrich, Jeff Okamoto, Anno | |
c2960299 | 816 | Siegel, Thomas Neumann, Paul Marquess, Charles Bailey, myself and others. |
3b35bae3 AD |
817 | |
818 | Larry Wall designed the elegant inherited bootstrap mechanism and | |
819 | implemented the first Perl 5 dynamic loader using it. | |
820 | ||
ff7f3c60 NIS |
821 | Solaris global loading added by Nick Ing-Simmons with design/coding |
822 | assistance from Tim Bunce, January 1996. | |
823 | ||
3b35bae3 | 824 | =cut |
03c9e98c GS |
825 | EOT |
826 | ||
827 | close OUT or die $!; | |
828 |