Commit | Line | Data |
03c9e98c |
1 | |
2 | use Config; |
3 | |
4 | sub to_string { |
5 | my ($value) = @_; |
6 | $value =~ s/\\/\\\\'/g; |
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 |
17 | package DynaLoader; |
18 | |
8e07c86e |
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 | |
fb73857a |
31 | $VERSION = $VERSION = "1.03"; # 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 |
44 | # enable debug/trace messages from DynaLoader perl code |
45 | $dl_debug = $ENV{PERL_DL_DEBUG} || 0 unless defined $dl_debug; |
46 | |
ff7f3c60 |
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 |
52 | # |
53 | # This is called as a class method $module->dl_load_flags. The |
54 | # definition here will be inherited and result on "default" loading |
55 | # behaviour unless a sub-class of DynaLoader defines its own version. |
56 | # |
57 | |
58 | sub dl_load_flags { 0x00 } |
59 | |
03c9e98c |
60 | # ($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 |
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'; |
8e07c86e |
75 | |
76 | @dl_require_symbols = (); # names of symbols we need |
77 | @dl_resolve_using = (); # names of files to link with |
78 | @dl_library_path = (); # path to look for files |
ff7f3c60 |
79 | @dl_librefs = (); # things we have loaded |
80 | @dl_modules = (); # Modules we have loaded |
8e07c86e |
81 | |
82 | # This is a fix to support DLD's unfortunate desire to relink -lc |
83 | @dl_resolve_using = dl_findfile('-lc') if $dlsrc eq "dl_dld.xs"; |
84 | |
85 | # Initialise @dl_library_path with the 'standard' library path |
86 | # for this platform as determined by Configure |
03c9e98c |
87 | |
88 | # push(@dl_library_path, split(' ', $Config::Config{'libpth'}); |
89 | EOT |
90 | |
91 | print OUT "push(\@dl_library_path, split(' ', ", |
92 | to_string($Config::Config{'libpth'}), "));\n"; |
93 | |
94 | print OUT <<'EOT'; |
8e07c86e |
95 | |
5cf1d1f1 |
96 | # Add to @dl_library_path any extra directories we can gather |
97 | # from environment variables. |
98 | push(@dl_library_path, split(/:/, $ENV{$Config::Config{ldlibpthname}})) |
99 | if exists $Config::Config{ldlibpthname} && |
100 | $Config::Config{ldlibpthname} ne '' && |
101 | exists $ENV{$Config::Config{ldlibpthname}} ;; |
102 | # E.g. HP-UX supports both its native SHLIB_PATH *and* LD_LIBRARY_PATH. |
8e07c86e |
103 | push(@dl_library_path, split(/:/, $ENV{LD_LIBRARY_PATH})) |
5cf1d1f1 |
104 | if exists $ENV{LD_LIBRARY_PATH}; |
8e07c86e |
105 | |
106 | # No prizes for guessing why we don't say 'bootstrap DynaLoader;' here. |
bb3913c7 |
107 | boot_DynaLoader('DynaLoader') if defined(&boot_DynaLoader) && |
108 | !defined(&dl_load_file); |
8e07c86e |
109 | |
110 | |
111 | if ($dl_debug) { |
112 | print STDERR "DynaLoader.pm loaded (@INC, @dl_library_path)\n"; |
113 | print STDERR "DynaLoader not linked into this perl\n" |
114 | unless defined(&boot_DynaLoader); |
115 | } |
116 | |
117 | 1; # End of main code |
118 | |
119 | |
fb73857a |
120 | sub croak { require Carp; Carp::croak(@_) } |
121 | |
8e07c86e |
122 | # The bootstrap function cannot be autoloaded (without complications) |
123 | # so we define it here: |
124 | |
125 | sub bootstrap { |
126 | # use local vars to enable $module.bs script to edit values |
127 | local(@args) = @_; |
128 | local($module) = $args[0]; |
129 | local(@dirs, $file); |
130 | |
fb73857a |
131 | unless ($module) { |
132 | require Carp; |
133 | Carp::confess("Usage: DynaLoader::bootstrap(module)"); |
134 | } |
8e07c86e |
135 | |
136 | # A common error on platforms which don't support dynamic loading. |
137 | # Since it's fatal and potentially confusing we give a detailed message. |
fb73857a |
138 | croak("Can't load module $module, dynamic loading not available in this perl.\n". |
8e07c86e |
139 | " (You may need to build a new perl executable which either supports\n". |
140 | " dynamic loading or has the $module module statically linked into it.)\n") |
141 | unless defined(&dl_load_file); |
142 | |
143 | my @modparts = split(/::/,$module); |
144 | my $modfname = $modparts[-1]; |
145 | |
146 | # Some systems have restrictions on files names for DLL's etc. |
147 | # mod2fname returns appropriate file base name (typically truncated) |
148 | # It may also edit @modparts if required. |
149 | $modfname = &mod2fname(\@modparts) if defined &mod2fname; |
150 | |
151 | my $modpname = join('/',@modparts); |
152 | |
153 | print STDERR "DynaLoader::bootstrap for $module ", |
154 | "(auto/$modpname/$modfname.$dl_dlext)\n" if $dl_debug; |
155 | |
156 | foreach (@INC) { |
54d6a3b3 |
157 | chop($_ = VMS::Filespec::unixpath($_)) if $Is_VMS; |
8e07c86e |
158 | my $dir = "$_/auto/$modpname"; |
159 | next unless -d $dir; # skip over uninteresting directories |
160 | |
161 | # check for common cases to avoid autoload of dl_findfile |
fb73857a |
162 | my $try = "$dir/$modfname.$dl_dlext"; |
163 | last if $file = ($do_expand) ? dl_expandspec($try) : (-f $try && $try); |
8e07c86e |
164 | |
165 | # no luck here, save dir for possible later dl_findfile search |
fb73857a |
166 | push @dirs, $dir; |
8e07c86e |
167 | } |
168 | # last resort, let dl_findfile have a go in all known locations |
fb73857a |
169 | $file = dl_findfile(map("-L$_",@dirs,@INC), $modfname) unless $file; |
8e07c86e |
170 | |
fb73857a |
171 | croak("Can't locate loadable object for module $module in \@INC (\@INC contains: @INC)") |
172 | unless $file; # wording similar to error from 'require' |
8e07c86e |
173 | |
174 | my $bootname = "boot_$module"; |
175 | $bootname =~ s/\W/_/g; |
176 | @dl_require_symbols = ($bootname); |
177 | |
178 | # Execute optional '.bootstrap' perl script for this module. |
179 | # The .bs file can be used to configure @dl_resolve_using etc to |
180 | # match the needs of the individual module on this architecture. |
181 | my $bs = $file; |
3f45a6dd |
182 | $bs =~ s/(\.\w+)?(;\d*)?$/\.bs/; # look for .bs 'beside' the library |
8e07c86e |
183 | if (-s $bs) { # only read file if it's not empty |
d404d5bf |
184 | print STDERR "BS: $bs ($^O, $dlsrc)\n" if $dl_debug; |
8e07c86e |
185 | eval { do $bs; }; |
186 | warn "$bs: $@\n" if $@; |
187 | } |
188 | |
189 | # Many dynamic extension loading problems will appear to come from |
190 | # this section of code: XYZ failed at line 123 of DynaLoader.pm. |
191 | # Often these errors are actually occurring in the initialisation |
192 | # C code of the extension XS file. Perl reports the error as being |
193 | # in this perl code simply because this was the last perl code |
194 | # it executed. |
195 | |
ff7f3c60 |
196 | my $libref = dl_load_file($file, $module->dl_load_flags) or |
549a6b10 |
197 | croak("Can't load '$file' for module $module: ".dl_error()); |
8e07c86e |
198 | |
ff7f3c60 |
199 | push(@dl_librefs,$libref); # record loaded object |
200 | |
8e07c86e |
201 | my @unresolved = dl_undef_symbols(); |
fb73857a |
202 | if (@unresolved) { |
203 | require Carp; |
204 | Carp::carp("Undefined symbols present after loading $file: @unresolved\n"); |
205 | } |
8e07c86e |
206 | |
207 | my $boot_symbol_ref = dl_find_symbol($libref, $bootname) or |
fb73857a |
208 | croak("Can't find '$bootname' symbol in $file\n"); |
8e07c86e |
209 | |
210 | my $xs = dl_install_xsub("${module}::bootstrap", $boot_symbol_ref, $file); |
211 | |
ff7f3c60 |
212 | push(@dl_modules, $module); # record loaded module |
213 | |
8e07c86e |
214 | # See comment block above |
215 | &$xs(@args); |
216 | } |
217 | |
218 | |
fb73857a |
219 | #sub _check_file { # private utility to handle dl_expandspec vs -f tests |
220 | # my($file) = @_; |
221 | # return $file if (!$do_expand && -f $file); # the common case |
222 | # return $file if ( $do_expand && ($file=dl_expandspec($file))); |
223 | # return undef; |
224 | #} |
8e07c86e |
225 | |
226 | |
227 | # Let autosplit and the autoloader deal with these functions: |
228 | __END__ |
229 | |
230 | |
231 | sub dl_findfile { |
232 | # Read ext/DynaLoader/DynaLoader.doc for detailed information. |
233 | # This function does not automatically consider the architecture |
234 | # or the perl library auto directories. |
235 | my (@args) = @_; |
236 | my (@dirs, $dir); # which directories to search |
237 | my (@found); # full paths to real files we have found |
03c9e98c |
238 | EOT |
239 | |
240 | print OUT ' my $dl_ext= ' . to_string($Config::Config{'dlext'}) . |
241 | "; # \$Config::Config{'dlext'} suffix for perl extensions\n"; |
242 | print OUT ' my $dl_so = ' . to_string($Config::Config{'so'}) . |
243 | "; # \$Config::Config{'so'} suffix for shared libraries\n"; |
244 | |
245 | print OUT <<'EOT'; |
8e07c86e |
246 | |
247 | print STDERR "dl_findfile(@args)\n" if $dl_debug; |
248 | |
249 | # accumulate directories but process files as they appear |
250 | arg: foreach(@args) { |
251 | # Special fast case: full filepath requires no search |
54d6a3b3 |
252 | if ($Is_VMS && m%[:>/\]]% && -f $_) { |
253 | push(@found,dl_expandspec(VMS::Filespec::vmsify($_))); |
254 | last arg unless wantarray; |
255 | next; |
256 | } |
257 | elsif (m:/: && -f $_ && !$do_expand) { |
8e07c86e |
258 | push(@found,$_); |
259 | last arg unless wantarray; |
260 | next; |
261 | } |
262 | |
263 | # Deal with directories first: |
264 | # Using a -L prefix is the preferred option (faster and more robust) |
265 | if (m:^-L:) { s/^-L//; push(@dirs, $_); next; } |
266 | |
267 | # Otherwise we try to try to spot directories by a heuristic |
268 | # (this is a more complicated issue than it first appears) |
269 | if (m:/: && -d $_) { push(@dirs, $_); next; } |
270 | |
271 | # VMS: we may be using native VMS directry syntax instead of |
272 | # Unix emulation, so check this as well |
54d6a3b3 |
273 | if ($Is_VMS && /[:>\]]/ && -d $_) { push(@dirs, $_); next; } |
8e07c86e |
274 | |
275 | # Only files should get this far... |
276 | my(@names, $name); # what filenames to look for |
277 | if (m:-l: ) { # convert -lname to appropriate library name |
278 | s/-l//; |
279 | push(@names,"lib$_.$dl_so"); |
280 | push(@names,"lib$_.a"); |
281 | } else { # Umm, a bare name. Try various alternatives: |
282 | # these should be ordered with the most likely first |
d404d5bf |
283 | push(@names,"$_.$dl_ext") unless m/\.$dl_ext$/o; |
8e07c86e |
284 | push(@names,"$_.$dl_so") unless m/\.$dl_so$/o; |
285 | push(@names,"lib$_.$dl_so") unless m:/:; |
8e07c86e |
286 | push(@names,"$_.a") if !m/\.a$/ and $dlsrc eq "dl_dld.xs"; |
287 | push(@names, $_); |
288 | } |
289 | foreach $dir (@dirs, @dl_library_path) { |
290 | next unless -d $dir; |
54d6a3b3 |
291 | chop($dir = VMS::Filespec::unixpath($dir)) if $Is_VMS; |
8e07c86e |
292 | foreach $name (@names) { |
293 | my($file) = "$dir/$name"; |
294 | print STDERR " checking in $dir for $name\n" if $dl_debug; |
fb73857a |
295 | $file = ($do_expand) ? dl_expandspec($file) : (-f $file && $file); |
296 | #$file = _check_file($file); |
8e07c86e |
297 | if ($file) { |
298 | push(@found, $file); |
299 | next arg; # no need to look any further |
300 | } |
301 | } |
302 | } |
303 | } |
304 | if ($dl_debug) { |
305 | foreach(@dirs) { |
306 | print STDERR " dl_findfile ignored non-existent directory: $_\n" unless -d $_; |
307 | } |
308 | print STDERR "dl_findfile found: @found\n"; |
309 | } |
310 | return $found[0] unless wantarray; |
311 | @found; |
312 | } |
313 | |
314 | |
315 | sub dl_expandspec { |
316 | my($spec) = @_; |
317 | # Optional function invoked if DynaLoader.pm sets $do_expand. |
318 | # Most systems do not require or use this function. |
319 | # Some systems may implement it in the dl_*.xs file in which case |
320 | # this autoload version will not be called but is harmless. |
321 | |
322 | # This function is designed to deal with systems which treat some |
323 | # 'filenames' in a special way. For example VMS 'Logical Names' |
324 | # (something like unix environment variables - but different). |
325 | # This function should recognise such names and expand them into |
326 | # full file paths. |
327 | # Must return undef if $spec is invalid or file does not exist. |
328 | |
329 | my $file = $spec; # default output to input |
330 | |
d404d5bf |
331 | if ($Is_VMS) { # dl_expandspec should be defined in dl_vms.xs |
fb73857a |
332 | require Carp; |
4633a7c4 |
333 | Carp::croak("dl_expandspec: should be defined in XS file!\n"); |
8e07c86e |
334 | } else { |
335 | return undef unless -f $file; |
336 | } |
337 | print STDERR "dl_expandspec($spec) => $file\n" if $dl_debug; |
338 | $file; |
339 | } |
340 | |
ff7f3c60 |
341 | sub dl_find_symbol_anywhere |
342 | { |
343 | my $sym = shift; |
344 | my $libref; |
345 | foreach $libref (@dl_librefs) { |
346 | my $symref = dl_find_symbol($libref,$sym); |
347 | return $symref if $symref; |
348 | } |
349 | return undef; |
350 | } |
8e07c86e |
351 | |
3b35bae3 |
352 | =head1 NAME |
353 | |
354 | DynaLoader - Dynamically load C libraries into Perl code |
355 | |
ff7f3c60 |
356 | dl_error(), dl_findfile(), dl_expandspec(), dl_load_file(), dl_find_symbol(), dl_find_symbol_anywhere(), dl_undef_symbols(), dl_install_xsub(), dl_load_flags(), bootstrap() - routines used by DynaLoader modules |
3b35bae3 |
357 | |
358 | =head1 SYNOPSIS |
359 | |
8e07c86e |
360 | package YourPackage; |
3b35bae3 |
361 | require DynaLoader; |
c2960299 |
362 | @ISA = qw(... DynaLoader ...); |
8e07c86e |
363 | bootstrap YourPackage; |
3b35bae3 |
364 | |
ff7f3c60 |
365 | # optional method for 'global' loading |
366 | sub dl_load_flags { 0x01 } |
367 | |
3b35bae3 |
368 | |
369 | =head1 DESCRIPTION |
370 | |
c2960299 |
371 | This document defines a standard generic interface to the dynamic |
3b35bae3 |
372 | linking mechanisms available on many platforms. Its primary purpose is |
373 | to implement automatic dynamic loading of Perl modules. |
374 | |
c2960299 |
375 | This document serves as both a specification for anyone wishing to |
376 | implement the DynaLoader for a new platform and as a guide for |
377 | anyone wishing to use the DynaLoader directly in an application. |
378 | |
3b35bae3 |
379 | The DynaLoader is designed to be a very simple high-level |
380 | interface that is sufficiently general to cover the requirements |
381 | of SunOS, HP-UX, NeXT, Linux, VMS and other platforms. |
382 | |
c2960299 |
383 | It is also hoped that the interface will cover the needs of OS/2, NT |
384 | etc and also allow pseudo-dynamic linking (using C<ld -A> at runtime). |
3b35bae3 |
385 | |
386 | It must be stressed that the DynaLoader, by itself, is practically |
387 | useless for accessing non-Perl libraries because it provides almost no |
388 | Perl-to-C 'glue'. There is, for example, no mechanism for calling a C |
03c9e98c |
389 | library function or supplying arguments. A C::DynaLib module |
90248788 |
390 | is available from CPAN sites which performs that function for some |
391 | common system types. |
3b35bae3 |
392 | |
393 | DynaLoader Interface Summary |
394 | |
395 | @dl_library_path |
396 | @dl_resolve_using |
397 | @dl_require_symbols |
398 | $dl_debug |
ff7f3c60 |
399 | @dl_librefs |
400 | @dl_modules |
3b35bae3 |
401 | Implemented in: |
402 | bootstrap($modulename) Perl |
403 | @filepaths = dl_findfile(@names) Perl |
ff7f3c60 |
404 | $flags = $modulename->dl_load_flags Perl |
405 | $symref = dl_find_symbol_anywhere($symbol) Perl |
3b35bae3 |
406 | |
ff7f3c60 |
407 | $libref = dl_load_file($filename, $flags) C |
3b35bae3 |
408 | $symref = dl_find_symbol($libref, $symbol) C |
409 | @symbols = dl_undef_symbols() C |
410 | dl_install_xsub($name, $symref [, $filename]) C |
411 | $message = dl_error C |
412 | |
413 | =over 4 |
414 | |
415 | =item @dl_library_path |
416 | |
417 | The standard/default list of directories in which dl_findfile() will |
418 | search for libraries etc. Directories are searched in order: |
419 | $dl_library_path[0], [1], ... etc |
420 | |
421 | @dl_library_path is initialised to hold the list of 'normal' directories |
422 | (F</usr/lib>, etc) determined by B<Configure> (C<$Config{'libpth'}>). This should |
423 | ensure portability across a wide range of platforms. |
424 | |
425 | @dl_library_path should also be initialised with any other directories |
426 | that can be determined from the environment at runtime (such as |
427 | LD_LIBRARY_PATH for SunOS). |
428 | |
429 | After initialisation @dl_library_path can be manipulated by an |
430 | application using push and unshift before calling dl_findfile(). |
431 | Unshift can be used to add directories to the front of the search order |
432 | either to save search time or to override libraries with the same name |
433 | in the 'normal' directories. |
434 | |
435 | The load function that dl_load_file() calls may require an absolute |
436 | pathname. The dl_findfile() function and @dl_library_path can be |
437 | used to search for and return the absolute pathname for the |
438 | library/object that you wish to load. |
439 | |
440 | =item @dl_resolve_using |
441 | |
442 | A list of additional libraries or other shared objects which can be |
443 | used to resolve any undefined symbols that might be generated by a |
444 | later call to load_file(). |
445 | |
446 | This is only required on some platforms which do not handle dependent |
7a2e2cd6 |
447 | libraries automatically. For example the Socket Perl extension |
448 | library (F<auto/Socket/Socket.so>) contains references to many socket |
449 | functions which need to be resolved when it's loaded. Most platforms |
450 | will automatically know where to find the 'dependent' library (e.g., |
451 | F</usr/lib/libsocket.so>). A few platforms need to be told the |
452 | location of the dependent library explicitly. Use @dl_resolve_using |
453 | for this. |
3b35bae3 |
454 | |
455 | Example usage: |
456 | |
457 | @dl_resolve_using = dl_findfile('-lsocket'); |
458 | |
459 | =item @dl_require_symbols |
460 | |
461 | A list of one or more symbol names that are in the library/object file |
462 | to be dynamically loaded. This is only required on some platforms. |
463 | |
ff7f3c60 |
464 | =item @dl_librefs |
465 | |
466 | An array of the handles returned by successful calls to dl_load_file(), |
467 | made by bootstrap, in the order in which they were loaded. |
468 | Can be used with dl_find_symbol() to look for a symbol in any of |
469 | the loaded files. |
470 | |
471 | =item @dl_modules |
472 | |
473 | An array of module (package) names that have been bootstrap'ed. |
474 | |
3b35bae3 |
475 | =item dl_error() |
476 | |
477 | Syntax: |
478 | |
479 | $message = dl_error(); |
480 | |
481 | Error message text from the last failed DynaLoader function. Note |
482 | that, similar to errno in unix, a successful function call does not |
483 | reset this message. |
484 | |
485 | Implementations should detect the error as soon as it occurs in any of |
486 | the other functions and save the corresponding message for later |
487 | retrieval. This will avoid problems on some platforms (such as SunOS) |
488 | where the error message is very temporary (e.g., dlerror()). |
489 | |
490 | =item $dl_debug |
491 | |
492 | Internal debugging messages are enabled when $dl_debug is set true. |
493 | Currently setting $dl_debug only affects the Perl side of the |
494 | DynaLoader. These messages should help an application developer to |
495 | resolve any DynaLoader usage problems. |
496 | |
497 | $dl_debug is set to C<$ENV{'PERL_DL_DEBUG'}> if defined. |
498 | |
499 | For the DynaLoader developer/porter there is a similar debugging |
500 | variable added to the C code (see dlutils.c) and enabled if Perl was |
501 | built with the B<-DDEBUGGING> flag. This can also be set via the |
502 | PERL_DL_DEBUG environment variable. Set to 1 for minimal information or |
503 | higher for more. |
504 | |
505 | =item dl_findfile() |
506 | |
507 | Syntax: |
508 | |
509 | @filepaths = dl_findfile(@names) |
510 | |
511 | Determine the full paths (including file suffix) of one or more |
512 | loadable files given their generic names and optionally one or more |
513 | directories. Searches directories in @dl_library_path by default and |
514 | returns an empty list if no files were found. |
515 | |
516 | Names can be specified in a variety of platform independent forms. Any |
517 | names in the form B<-lname> are converted into F<libname.*>, where F<.*> is |
518 | an appropriate suffix for the platform. |
519 | |
520 | If a name does not already have a suitable prefix and/or suffix then |
521 | the corresponding file will be searched for by trying combinations of |
522 | prefix and suffix appropriate to the platform: "$name.o", "lib$name.*" |
523 | and "$name". |
524 | |
525 | If any directories are included in @names they are searched before |
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526 | @dl_library_path. Directories may be specified as B<-Ldir>. Any other |
527 | names are treated as filenames to be searched for. |
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528 | |
529 | Using arguments of the form C<-Ldir> and C<-lname> is recommended. |
530 | |
531 | Example: |
532 | |
533 | @dl_resolve_using = dl_findfile(qw(-L/usr/5lib -lposix)); |
534 | |
535 | |
536 | =item dl_expandspec() |
537 | |
538 | Syntax: |
539 | |
540 | $filepath = dl_expandspec($spec) |
541 | |
542 | Some unusual systems, such as VMS, require special filename handling in |
543 | order to deal with symbolic names for files (i.e., VMS's Logical Names). |
544 | |
545 | To support these systems a dl_expandspec() function can be implemented |
546 | either in the F<dl_*.xs> file or code can be added to the autoloadable |
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547 | dl_expandspec() function in F<DynaLoader.pm>. See F<DynaLoader.pm> for |
548 | more information. |
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549 | |
550 | =item dl_load_file() |
551 | |
552 | Syntax: |
553 | |
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554 | $libref = dl_load_file($filename, $flags) |
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555 | |
556 | Dynamically load $filename, which must be the path to a shared object |
557 | or library. An opaque 'library reference' is returned as a handle for |
558 | the loaded object. Returns undef on error. |
559 | |
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560 | The $flags argument to alters dl_load_file behaviour. |
561 | Assigned bits: |
562 | |
563 | 0x01 make symbols available for linking later dl_load_file's. |
564 | (only known to work on Solaris 2 using dlopen(RTLD_GLOBAL)) |
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565 | (ignored under VMS; this is a normal part of image linking) |
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566 | |
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567 | (On systems that provide a handle for the loaded object such as SunOS |
568 | and HPUX, $libref will be that handle. On other systems $libref will |
569 | typically be $filename or a pointer to a buffer containing $filename. |
570 | The application should not examine or alter $libref in any way.) |
571 | |
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572 | This is the function that does the real work. It should use the |
573 | current values of @dl_require_symbols and @dl_resolve_using if required. |
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574 | |
575 | SunOS: dlopen($filename) |
576 | HP-UX: shl_load($filename) |
577 | Linux: dld_create_reference(@dl_require_symbols); dld_link($filename) |
578 | NeXT: rld_load($filename, @dl_resolve_using) |
579 | VMS: lib$find_image_symbol($filename,$dl_require_symbols[0]) |
580 | |
ff7f3c60 |
581 | (The dlopen() function is also used by Solaris and some versions of |
582 | Linux, and is a common choice when providing a "wrapper" on other |
583 | mechanisms as is done in the OS/2 port.) |
584 | |
585 | =item dl_loadflags() |
586 | |
587 | Syntax: |
588 | |
589 | $flags = dl_loadflags $modulename; |
590 | |
591 | Designed to be a method call, and to be overridden by a derived class |
592 | (i.e. a class which has DynaLoader in its @ISA). The definition in |
593 | DynaLoader itself returns 0, which produces standard behavior from |
594 | dl_load_file(). |
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595 | |
596 | =item dl_find_symbol() |
597 | |
598 | Syntax: |
599 | |
600 | $symref = dl_find_symbol($libref, $symbol) |
601 | |
602 | Return the address of the symbol $symbol or C<undef> if not found. If the |
603 | target system has separate functions to search for symbols of different |
604 | types then dl_find_symbol() should search for function symbols first and |
605 | then other types. |
606 | |
607 | The exact manner in which the address is returned in $symref is not |
608 | currently defined. The only initial requirement is that $symref can |
609 | be passed to, and understood by, dl_install_xsub(). |
610 | |
611 | SunOS: dlsym($libref, $symbol) |
612 | HP-UX: shl_findsym($libref, $symbol) |
613 | Linux: dld_get_func($symbol) and/or dld_get_symbol($symbol) |
614 | NeXT: rld_lookup("_$symbol") |
615 | VMS: lib$find_image_symbol($libref,$symbol) |
616 | |
617 | |
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618 | =item dl_find_symbol_anywhere() |
619 | |
620 | Syntax: |
621 | |
622 | $symref = dl_find_symbol_anywhere($symbol) |
623 | |
624 | Applies dl_find_symbol() to the members of @dl_librefs and returns |
625 | the first match found. |
626 | |
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627 | =item dl_undef_symbols() |
628 | |
629 | Example |
630 | |
631 | @symbols = dl_undef_symbols() |
632 | |
633 | Return a list of symbol names which remain undefined after load_file(). |
634 | Returns C<()> if not known. Don't worry if your platform does not provide |
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635 | a mechanism for this. Most do not need it and hence do not provide it, |
636 | they just return an empty list. |
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637 | |
638 | |
639 | =item dl_install_xsub() |
640 | |
641 | Syntax: |
642 | |
643 | dl_install_xsub($perl_name, $symref [, $filename]) |
644 | |
645 | Create a new Perl external subroutine named $perl_name using $symref as |
646 | a pointer to the function which implements the routine. This is simply |
647 | a direct call to newXSUB(). Returns a reference to the installed |
648 | function. |
649 | |
650 | The $filename parameter is used by Perl to identify the source file for |
651 | the function if required by die(), caller() or the debugger. If |
652 | $filename is not defined then "DynaLoader" will be used. |
653 | |
654 | |
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655 | =item bootstrap() |
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656 | |
657 | Syntax: |
658 | |
659 | bootstrap($module) |
660 | |
661 | This is the normal entry point for automatic dynamic loading in Perl. |
662 | |
663 | It performs the following actions: |
664 | |
665 | =over 8 |
666 | |
667 | =item * |
668 | |
669 | locates an auto/$module directory by searching @INC |
670 | |
671 | =item * |
672 | |
673 | uses dl_findfile() to determine the filename to load |
674 | |
675 | =item * |
676 | |
677 | sets @dl_require_symbols to C<("boot_$module")> |
678 | |
679 | =item * |
680 | |
681 | executes an F<auto/$module/$module.bs> file if it exists |
682 | (typically used to add to @dl_resolve_using any files which |
683 | are required to load the module on the current platform) |
684 | |
685 | =item * |
686 | |
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687 | calls dl_load_flags() to determine how to load the file. |
688 | |
689 | =item * |
690 | |
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691 | calls dl_load_file() to load the file |
692 | |
693 | =item * |
694 | |
695 | calls dl_undef_symbols() and warns if any symbols are undefined |
696 | |
697 | =item * |
698 | |
699 | calls dl_find_symbol() for "boot_$module" |
700 | |
701 | =item * |
702 | |
703 | calls dl_install_xsub() to install it as "${module}::bootstrap" |
704 | |
705 | =item * |
706 | |
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707 | calls &{"${module}::bootstrap"} to bootstrap the module (actually |
708 | it uses the function reference returned by dl_install_xsub for speed) |
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709 | |
710 | =back |
711 | |
712 | =back |
713 | |
714 | |
715 | =head1 AUTHOR |
716 | |
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717 | Tim Bunce, 11 August 1994. |
718 | |
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719 | This interface is based on the work and comments of (in no particular |
720 | order): Larry Wall, Robert Sanders, Dean Roehrich, Jeff Okamoto, Anno |
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721 | Siegel, Thomas Neumann, Paul Marquess, Charles Bailey, myself and others. |
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722 | |
723 | Larry Wall designed the elegant inherited bootstrap mechanism and |
724 | implemented the first Perl 5 dynamic loader using it. |
725 | |
ff7f3c60 |
726 | Solaris global loading added by Nick Ing-Simmons with design/coding |
727 | assistance from Tim Bunce, January 1996. |
728 | |
3b35bae3 |
729 | =cut |
03c9e98c |
730 | EOT |
731 | |
732 | close OUT or die $!; |
733 | |