Commit | Line | Data |
---|---|---|
03c9e98c GS |
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 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 | ||
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 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'; |
8e07c86e AD |
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 NIS |
79 | @dl_librefs = (); # things we have loaded |
80 | @dl_modules = (); # Modules we have loaded | |
8e07c86e AD |
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 GS |
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 AD |
95 | |
96 | # Add to @dl_library_path any extra directories we can gather from | |
97 | # environment variables. So far LD_LIBRARY_PATH is the only known | |
98 | # variable used for this purpose. Others may be added later. | |
99 | push(@dl_library_path, split(/:/, $ENV{LD_LIBRARY_PATH})) | |
100 | if $ENV{LD_LIBRARY_PATH}; | |
101 | ||
102 | ||
103 | # No prizes for guessing why we don't say 'bootstrap DynaLoader;' here. | |
340937ab JD |
104 | boot_DynaLoader('DynaLoader') if defined(&boot_DynaLoader) && |
105 | !defined(&dl_load_file); | |
8e07c86e AD |
106 | |
107 | ||
108 | if ($dl_debug) { | |
109 | print STDERR "DynaLoader.pm loaded (@INC, @dl_library_path)\n"; | |
110 | print STDERR "DynaLoader not linked into this perl\n" | |
111 | unless defined(&boot_DynaLoader); | |
112 | } | |
113 | ||
114 | 1; # End of main code | |
115 | ||
116 | ||
fb73857a | 117 | sub croak { require Carp; Carp::croak(@_) } |
118 | ||
8e07c86e AD |
119 | # The bootstrap function cannot be autoloaded (without complications) |
120 | # so we define it here: | |
121 | ||
122 | sub bootstrap { | |
123 | # use local vars to enable $module.bs script to edit values | |
124 | local(@args) = @_; | |
125 | local($module) = $args[0]; | |
126 | local(@dirs, $file); | |
127 | ||
fb73857a | 128 | unless ($module) { |
129 | require Carp; | |
130 | Carp::confess("Usage: DynaLoader::bootstrap(module)"); | |
131 | } | |
8e07c86e AD |
132 | |
133 | # A common error on platforms which don't support dynamic loading. | |
134 | # Since it's fatal and potentially confusing we give a detailed message. | |
fb73857a | 135 | croak("Can't load module $module, dynamic loading not available in this perl.\n". |
8e07c86e AD |
136 | " (You may need to build a new perl executable which either supports\n". |
137 | " dynamic loading or has the $module module statically linked into it.)\n") | |
138 | unless defined(&dl_load_file); | |
139 | ||
140 | my @modparts = split(/::/,$module); | |
141 | my $modfname = $modparts[-1]; | |
142 | ||
143 | # Some systems have restrictions on files names for DLL's etc. | |
144 | # mod2fname returns appropriate file base name (typically truncated) | |
145 | # It may also edit @modparts if required. | |
146 | $modfname = &mod2fname(\@modparts) if defined &mod2fname; | |
147 | ||
148 | my $modpname = join('/',@modparts); | |
149 | ||
150 | print STDERR "DynaLoader::bootstrap for $module ", | |
151 | "(auto/$modpname/$modfname.$dl_dlext)\n" if $dl_debug; | |
152 | ||
153 | foreach (@INC) { | |
54d6a3b3 | 154 | chop($_ = VMS::Filespec::unixpath($_)) if $Is_VMS; |
8e07c86e AD |
155 | my $dir = "$_/auto/$modpname"; |
156 | next unless -d $dir; # skip over uninteresting directories | |
157 | ||
158 | # check for common cases to avoid autoload of dl_findfile | |
fb73857a | 159 | my $try = "$dir/$modfname.$dl_dlext"; |
160 | last if $file = ($do_expand) ? dl_expandspec($try) : (-f $try && $try); | |
8e07c86e AD |
161 | |
162 | # no luck here, save dir for possible later dl_findfile search | |
fb73857a | 163 | push @dirs, $dir; |
8e07c86e AD |
164 | } |
165 | # last resort, let dl_findfile have a go in all known locations | |
fb73857a | 166 | $file = dl_findfile(map("-L$_",@dirs,@INC), $modfname) unless $file; |
8e07c86e | 167 | |
fb73857a | 168 | croak("Can't locate loadable object for module $module in \@INC (\@INC contains: @INC)") |
169 | unless $file; # wording similar to error from 'require' | |
8e07c86e AD |
170 | |
171 | my $bootname = "boot_$module"; | |
172 | $bootname =~ s/\W/_/g; | |
173 | @dl_require_symbols = ($bootname); | |
174 | ||
175 | # Execute optional '.bootstrap' perl script for this module. | |
176 | # The .bs file can be used to configure @dl_resolve_using etc to | |
177 | # match the needs of the individual module on this architecture. | |
178 | my $bs = $file; | |
179 | $bs =~ s/(\.\w+)?$/\.bs/; # look for .bs 'beside' the library | |
180 | if (-s $bs) { # only read file if it's not empty | |
d404d5bf | 181 | print STDERR "BS: $bs ($^O, $dlsrc)\n" if $dl_debug; |
8e07c86e AD |
182 | eval { do $bs; }; |
183 | warn "$bs: $@\n" if $@; | |
184 | } | |
185 | ||
186 | # Many dynamic extension loading problems will appear to come from | |
187 | # this section of code: XYZ failed at line 123 of DynaLoader.pm. | |
188 | # Often these errors are actually occurring in the initialisation | |
189 | # C code of the extension XS file. Perl reports the error as being | |
190 | # in this perl code simply because this was the last perl code | |
191 | # it executed. | |
192 | ||
ff7f3c60 | 193 | my $libref = dl_load_file($file, $module->dl_load_flags) or |
fb73857a | 194 | croak("Can't load '$file' for module $module: ".dl_error()."\n"); |
8e07c86e | 195 | |
ff7f3c60 NIS |
196 | push(@dl_librefs,$libref); # record loaded object |
197 | ||
8e07c86e | 198 | my @unresolved = dl_undef_symbols(); |
fb73857a | 199 | if (@unresolved) { |
200 | require Carp; | |
201 | Carp::carp("Undefined symbols present after loading $file: @unresolved\n"); | |
202 | } | |
8e07c86e AD |
203 | |
204 | my $boot_symbol_ref = dl_find_symbol($libref, $bootname) or | |
fb73857a | 205 | croak("Can't find '$bootname' symbol in $file\n"); |
8e07c86e AD |
206 | |
207 | my $xs = dl_install_xsub("${module}::bootstrap", $boot_symbol_ref, $file); | |
208 | ||
ff7f3c60 NIS |
209 | push(@dl_modules, $module); # record loaded module |
210 | ||
8e07c86e AD |
211 | # See comment block above |
212 | &$xs(@args); | |
213 | } | |
214 | ||
215 | ||
fb73857a | 216 | #sub _check_file { # private utility to handle dl_expandspec vs -f tests |
217 | # my($file) = @_; | |
218 | # return $file if (!$do_expand && -f $file); # the common case | |
219 | # return $file if ( $do_expand && ($file=dl_expandspec($file))); | |
220 | # return undef; | |
221 | #} | |
8e07c86e AD |
222 | |
223 | ||
224 | # Let autosplit and the autoloader deal with these functions: | |
225 | __END__ | |
226 | ||
227 | ||
228 | sub dl_findfile { | |
229 | # Read ext/DynaLoader/DynaLoader.doc for detailed information. | |
230 | # This function does not automatically consider the architecture | |
231 | # or the perl library auto directories. | |
232 | my (@args) = @_; | |
233 | my (@dirs, $dir); # which directories to search | |
234 | my (@found); # full paths to real files we have found | |
03c9e98c GS |
235 | EOT |
236 | ||
237 | print OUT ' my $dl_ext= ' . to_string($Config::Config{'dlext'}) . | |
238 | "; # \$Config::Config{'dlext'} suffix for perl extensions\n"; | |
239 | print OUT ' my $dl_so = ' . to_string($Config::Config{'so'}) . | |
240 | "; # \$Config::Config{'so'} suffix for shared libraries\n"; | |
241 | ||
242 | print OUT <<'EOT'; | |
8e07c86e AD |
243 | |
244 | print STDERR "dl_findfile(@args)\n" if $dl_debug; | |
245 | ||
246 | # accumulate directories but process files as they appear | |
247 | arg: foreach(@args) { | |
248 | # Special fast case: full filepath requires no search | |
54d6a3b3 | 249 | if ($Is_VMS && m%[:>/\]]% && -f $_) { |
250 | push(@found,dl_expandspec(VMS::Filespec::vmsify($_))); | |
251 | last arg unless wantarray; | |
252 | next; | |
253 | } | |
254 | elsif (m:/: && -f $_ && !$do_expand) { | |
8e07c86e AD |
255 | push(@found,$_); |
256 | last arg unless wantarray; | |
257 | next; | |
258 | } | |
259 | ||
260 | # Deal with directories first: | |
261 | # Using a -L prefix is the preferred option (faster and more robust) | |
262 | if (m:^-L:) { s/^-L//; push(@dirs, $_); next; } | |
263 | ||
264 | # Otherwise we try to try to spot directories by a heuristic | |
265 | # (this is a more complicated issue than it first appears) | |
266 | if (m:/: && -d $_) { push(@dirs, $_); next; } | |
267 | ||
268 | # VMS: we may be using native VMS directry syntax instead of | |
269 | # Unix emulation, so check this as well | |
54d6a3b3 | 270 | if ($Is_VMS && /[:>\]]/ && -d $_) { push(@dirs, $_); next; } |
8e07c86e AD |
271 | |
272 | # Only files should get this far... | |
273 | my(@names, $name); # what filenames to look for | |
274 | if (m:-l: ) { # convert -lname to appropriate library name | |
275 | s/-l//; | |
276 | push(@names,"lib$_.$dl_so"); | |
277 | push(@names,"lib$_.a"); | |
278 | } else { # Umm, a bare name. Try various alternatives: | |
279 | # these should be ordered with the most likely first | |
d404d5bf | 280 | push(@names,"$_.$dl_ext") unless m/\.$dl_ext$/o; |
8e07c86e AD |
281 | push(@names,"$_.$dl_so") unless m/\.$dl_so$/o; |
282 | push(@names,"lib$_.$dl_so") unless m:/:; | |
8e07c86e AD |
283 | push(@names,"$_.a") if !m/\.a$/ and $dlsrc eq "dl_dld.xs"; |
284 | push(@names, $_); | |
285 | } | |
286 | foreach $dir (@dirs, @dl_library_path) { | |
287 | next unless -d $dir; | |
54d6a3b3 | 288 | chop($dir = VMS::Filespec::unixpath($dir)) if $Is_VMS; |
8e07c86e AD |
289 | foreach $name (@names) { |
290 | my($file) = "$dir/$name"; | |
291 | print STDERR " checking in $dir for $name\n" if $dl_debug; | |
fb73857a | 292 | $file = ($do_expand) ? dl_expandspec($file) : (-f $file && $file); |
293 | #$file = _check_file($file); | |
8e07c86e AD |
294 | if ($file) { |
295 | push(@found, $file); | |
296 | next arg; # no need to look any further | |
297 | } | |
298 | } | |
299 | } | |
300 | } | |
301 | if ($dl_debug) { | |
302 | foreach(@dirs) { | |
303 | print STDERR " dl_findfile ignored non-existent directory: $_\n" unless -d $_; | |
304 | } | |
305 | print STDERR "dl_findfile found: @found\n"; | |
306 | } | |
307 | return $found[0] unless wantarray; | |
308 | @found; | |
309 | } | |
310 | ||
311 | ||
312 | sub dl_expandspec { | |
313 | my($spec) = @_; | |
314 | # Optional function invoked if DynaLoader.pm sets $do_expand. | |
315 | # Most systems do not require or use this function. | |
316 | # Some systems may implement it in the dl_*.xs file in which case | |
317 | # this autoload version will not be called but is harmless. | |
318 | ||
319 | # This function is designed to deal with systems which treat some | |
320 | # 'filenames' in a special way. For example VMS 'Logical Names' | |
321 | # (something like unix environment variables - but different). | |
322 | # This function should recognise such names and expand them into | |
323 | # full file paths. | |
324 | # Must return undef if $spec is invalid or file does not exist. | |
325 | ||
326 | my $file = $spec; # default output to input | |
327 | ||
d404d5bf | 328 | if ($Is_VMS) { # dl_expandspec should be defined in dl_vms.xs |
fb73857a | 329 | require Carp; |
4633a7c4 | 330 | Carp::croak("dl_expandspec: should be defined in XS file!\n"); |
8e07c86e AD |
331 | } else { |
332 | return undef unless -f $file; | |
333 | } | |
334 | print STDERR "dl_expandspec($spec) => $file\n" if $dl_debug; | |
335 | $file; | |
336 | } | |
337 | ||
ff7f3c60 NIS |
338 | sub dl_find_symbol_anywhere |
339 | { | |
340 | my $sym = shift; | |
341 | my $libref; | |
342 | foreach $libref (@dl_librefs) { | |
343 | my $symref = dl_find_symbol($libref,$sym); | |
344 | return $symref if $symref; | |
345 | } | |
346 | return undef; | |
347 | } | |
8e07c86e | 348 | |
3b35bae3 AD |
349 | =head1 NAME |
350 | ||
351 | DynaLoader - Dynamically load C libraries into Perl code | |
352 | ||
ff7f3c60 | 353 | 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 AD |
354 | |
355 | =head1 SYNOPSIS | |
356 | ||
8e07c86e | 357 | package YourPackage; |
3b35bae3 | 358 | require DynaLoader; |
c2960299 | 359 | @ISA = qw(... DynaLoader ...); |
8e07c86e | 360 | bootstrap YourPackage; |
3b35bae3 | 361 | |
ff7f3c60 NIS |
362 | # optional method for 'global' loading |
363 | sub dl_load_flags { 0x01 } | |
364 | ||
3b35bae3 AD |
365 | |
366 | =head1 DESCRIPTION | |
367 | ||
c2960299 | 368 | This document defines a standard generic interface to the dynamic |
3b35bae3 AD |
369 | linking mechanisms available on many platforms. Its primary purpose is |
370 | to implement automatic dynamic loading of Perl modules. | |
371 | ||
c2960299 AD |
372 | This document serves as both a specification for anyone wishing to |
373 | implement the DynaLoader for a new platform and as a guide for | |
374 | anyone wishing to use the DynaLoader directly in an application. | |
375 | ||
3b35bae3 AD |
376 | The DynaLoader is designed to be a very simple high-level |
377 | interface that is sufficiently general to cover the requirements | |
378 | of SunOS, HP-UX, NeXT, Linux, VMS and other platforms. | |
379 | ||
c2960299 AD |
380 | It is also hoped that the interface will cover the needs of OS/2, NT |
381 | etc and also allow pseudo-dynamic linking (using C<ld -A> at runtime). | |
3b35bae3 AD |
382 | |
383 | It must be stressed that the DynaLoader, by itself, is practically | |
384 | useless for accessing non-Perl libraries because it provides almost no | |
385 | Perl-to-C 'glue'. There is, for example, no mechanism for calling a C | |
03c9e98c | 386 | library function or supplying arguments. A C::DynaLib module |
90248788 TB |
387 | is available from CPAN sites which performs that function for some |
388 | common system types. | |
3b35bae3 AD |
389 | |
390 | DynaLoader Interface Summary | |
391 | ||
392 | @dl_library_path | |
393 | @dl_resolve_using | |
394 | @dl_require_symbols | |
395 | $dl_debug | |
ff7f3c60 NIS |
396 | @dl_librefs |
397 | @dl_modules | |
3b35bae3 AD |
398 | Implemented in: |
399 | bootstrap($modulename) Perl | |
400 | @filepaths = dl_findfile(@names) Perl | |
ff7f3c60 NIS |
401 | $flags = $modulename->dl_load_flags Perl |
402 | $symref = dl_find_symbol_anywhere($symbol) Perl | |
3b35bae3 | 403 | |
ff7f3c60 | 404 | $libref = dl_load_file($filename, $flags) C |
3b35bae3 AD |
405 | $symref = dl_find_symbol($libref, $symbol) C |
406 | @symbols = dl_undef_symbols() C | |
407 | dl_install_xsub($name, $symref [, $filename]) C | |
408 | $message = dl_error C | |
409 | ||
410 | =over 4 | |
411 | ||
412 | =item @dl_library_path | |
413 | ||
414 | The standard/default list of directories in which dl_findfile() will | |
415 | search for libraries etc. Directories are searched in order: | |
416 | $dl_library_path[0], [1], ... etc | |
417 | ||
418 | @dl_library_path is initialised to hold the list of 'normal' directories | |
419 | (F</usr/lib>, etc) determined by B<Configure> (C<$Config{'libpth'}>). This should | |
420 | ensure portability across a wide range of platforms. | |
421 | ||
422 | @dl_library_path should also be initialised with any other directories | |
423 | that can be determined from the environment at runtime (such as | |
424 | LD_LIBRARY_PATH for SunOS). | |
425 | ||
426 | After initialisation @dl_library_path can be manipulated by an | |
427 | application using push and unshift before calling dl_findfile(). | |
428 | Unshift can be used to add directories to the front of the search order | |
429 | either to save search time or to override libraries with the same name | |
430 | in the 'normal' directories. | |
431 | ||
432 | The load function that dl_load_file() calls may require an absolute | |
433 | pathname. The dl_findfile() function and @dl_library_path can be | |
434 | used to search for and return the absolute pathname for the | |
435 | library/object that you wish to load. | |
436 | ||
437 | =item @dl_resolve_using | |
438 | ||
439 | A list of additional libraries or other shared objects which can be | |
440 | used to resolve any undefined symbols that might be generated by a | |
441 | later call to load_file(). | |
442 | ||
443 | This is only required on some platforms which do not handle dependent | |
7a2e2cd6 | 444 | libraries automatically. For example the Socket Perl extension |
445 | library (F<auto/Socket/Socket.so>) contains references to many socket | |
446 | functions which need to be resolved when it's loaded. Most platforms | |
447 | will automatically know where to find the 'dependent' library (e.g., | |
448 | F</usr/lib/libsocket.so>). A few platforms need to be told the | |
449 | location of the dependent library explicitly. Use @dl_resolve_using | |
450 | for this. | |
3b35bae3 AD |
451 | |
452 | Example usage: | |
453 | ||
454 | @dl_resolve_using = dl_findfile('-lsocket'); | |
455 | ||
456 | =item @dl_require_symbols | |
457 | ||
458 | A list of one or more symbol names that are in the library/object file | |
459 | to be dynamically loaded. This is only required on some platforms. | |
460 | ||
ff7f3c60 NIS |
461 | =item @dl_librefs |
462 | ||
463 | An array of the handles returned by successful calls to dl_load_file(), | |
464 | made by bootstrap, in the order in which they were loaded. | |
465 | Can be used with dl_find_symbol() to look for a symbol in any of | |
466 | the loaded files. | |
467 | ||
468 | =item @dl_modules | |
469 | ||
470 | An array of module (package) names that have been bootstrap'ed. | |
471 | ||
3b35bae3 AD |
472 | =item dl_error() |
473 | ||
474 | Syntax: | |
475 | ||
476 | $message = dl_error(); | |
477 | ||
478 | Error message text from the last failed DynaLoader function. Note | |
479 | that, similar to errno in unix, a successful function call does not | |
480 | reset this message. | |
481 | ||
482 | Implementations should detect the error as soon as it occurs in any of | |
483 | the other functions and save the corresponding message for later | |
484 | retrieval. This will avoid problems on some platforms (such as SunOS) | |
485 | where the error message is very temporary (e.g., dlerror()). | |
486 | ||
487 | =item $dl_debug | |
488 | ||
489 | Internal debugging messages are enabled when $dl_debug is set true. | |
490 | Currently setting $dl_debug only affects the Perl side of the | |
491 | DynaLoader. These messages should help an application developer to | |
492 | resolve any DynaLoader usage problems. | |
493 | ||
494 | $dl_debug is set to C<$ENV{'PERL_DL_DEBUG'}> if defined. | |
495 | ||
496 | For the DynaLoader developer/porter there is a similar debugging | |
497 | variable added to the C code (see dlutils.c) and enabled if Perl was | |
498 | built with the B<-DDEBUGGING> flag. This can also be set via the | |
499 | PERL_DL_DEBUG environment variable. Set to 1 for minimal information or | |
500 | higher for more. | |
501 | ||
502 | =item dl_findfile() | |
503 | ||
504 | Syntax: | |
505 | ||
506 | @filepaths = dl_findfile(@names) | |
507 | ||
508 | Determine the full paths (including file suffix) of one or more | |
509 | loadable files given their generic names and optionally one or more | |
510 | directories. Searches directories in @dl_library_path by default and | |
511 | returns an empty list if no files were found. | |
512 | ||
513 | Names can be specified in a variety of platform independent forms. Any | |
514 | names in the form B<-lname> are converted into F<libname.*>, where F<.*> is | |
515 | an appropriate suffix for the platform. | |
516 | ||
517 | If a name does not already have a suitable prefix and/or suffix then | |
518 | the corresponding file will be searched for by trying combinations of | |
519 | prefix and suffix appropriate to the platform: "$name.o", "lib$name.*" | |
520 | and "$name". | |
521 | ||
522 | If any directories are included in @names they are searched before | |
c2960299 AD |
523 | @dl_library_path. Directories may be specified as B<-Ldir>. Any other |
524 | names are treated as filenames to be searched for. | |
3b35bae3 AD |
525 | |
526 | Using arguments of the form C<-Ldir> and C<-lname> is recommended. | |
527 | ||
528 | Example: | |
529 | ||
530 | @dl_resolve_using = dl_findfile(qw(-L/usr/5lib -lposix)); | |
531 | ||
532 | ||
533 | =item dl_expandspec() | |
534 | ||
535 | Syntax: | |
536 | ||
537 | $filepath = dl_expandspec($spec) | |
538 | ||
539 | Some unusual systems, such as VMS, require special filename handling in | |
540 | order to deal with symbolic names for files (i.e., VMS's Logical Names). | |
541 | ||
542 | To support these systems a dl_expandspec() function can be implemented | |
543 | either in the F<dl_*.xs> file or code can be added to the autoloadable | |
c2960299 AD |
544 | dl_expandspec() function in F<DynaLoader.pm>. See F<DynaLoader.pm> for |
545 | more information. | |
3b35bae3 AD |
546 | |
547 | =item dl_load_file() | |
548 | ||
549 | Syntax: | |
550 | ||
ff7f3c60 | 551 | $libref = dl_load_file($filename, $flags) |
3b35bae3 AD |
552 | |
553 | Dynamically load $filename, which must be the path to a shared object | |
554 | or library. An opaque 'library reference' is returned as a handle for | |
555 | the loaded object. Returns undef on error. | |
556 | ||
ff7f3c60 NIS |
557 | The $flags argument to alters dl_load_file behaviour. |
558 | Assigned bits: | |
559 | ||
560 | 0x01 make symbols available for linking later dl_load_file's. | |
561 | (only known to work on Solaris 2 using dlopen(RTLD_GLOBAL)) | |
f86702cc | 562 | (ignored under VMS; this is a normal part of image linking) |
ff7f3c60 | 563 | |
3b35bae3 AD |
564 | (On systems that provide a handle for the loaded object such as SunOS |
565 | and HPUX, $libref will be that handle. On other systems $libref will | |
566 | typically be $filename or a pointer to a buffer containing $filename. | |
567 | The application should not examine or alter $libref in any way.) | |
568 | ||
ff7f3c60 NIS |
569 | This is the function that does the real work. It should use the |
570 | current values of @dl_require_symbols and @dl_resolve_using if required. | |
3b35bae3 AD |
571 | |
572 | SunOS: dlopen($filename) | |
573 | HP-UX: shl_load($filename) | |
574 | Linux: dld_create_reference(@dl_require_symbols); dld_link($filename) | |
575 | NeXT: rld_load($filename, @dl_resolve_using) | |
576 | VMS: lib$find_image_symbol($filename,$dl_require_symbols[0]) | |
577 | ||
ff7f3c60 NIS |
578 | (The dlopen() function is also used by Solaris and some versions of |
579 | Linux, and is a common choice when providing a "wrapper" on other | |
580 | mechanisms as is done in the OS/2 port.) | |
581 | ||
582 | =item dl_loadflags() | |
583 | ||
584 | Syntax: | |
585 | ||
586 | $flags = dl_loadflags $modulename; | |
587 | ||
588 | Designed to be a method call, and to be overridden by a derived class | |
589 | (i.e. a class which has DynaLoader in its @ISA). The definition in | |
590 | DynaLoader itself returns 0, which produces standard behavior from | |
591 | dl_load_file(). | |
3b35bae3 AD |
592 | |
593 | =item dl_find_symbol() | |
594 | ||
595 | Syntax: | |
596 | ||
597 | $symref = dl_find_symbol($libref, $symbol) | |
598 | ||
599 | Return the address of the symbol $symbol or C<undef> if not found. If the | |
600 | target system has separate functions to search for symbols of different | |
601 | types then dl_find_symbol() should search for function symbols first and | |
602 | then other types. | |
603 | ||
604 | The exact manner in which the address is returned in $symref is not | |
605 | currently defined. The only initial requirement is that $symref can | |
606 | be passed to, and understood by, dl_install_xsub(). | |
607 | ||
608 | SunOS: dlsym($libref, $symbol) | |
609 | HP-UX: shl_findsym($libref, $symbol) | |
610 | Linux: dld_get_func($symbol) and/or dld_get_symbol($symbol) | |
611 | NeXT: rld_lookup("_$symbol") | |
612 | VMS: lib$find_image_symbol($libref,$symbol) | |
613 | ||
614 | ||
ff7f3c60 NIS |
615 | =item dl_find_symbol_anywhere() |
616 | ||
617 | Syntax: | |
618 | ||
619 | $symref = dl_find_symbol_anywhere($symbol) | |
620 | ||
621 | Applies dl_find_symbol() to the members of @dl_librefs and returns | |
622 | the first match found. | |
623 | ||
3b35bae3 AD |
624 | =item dl_undef_symbols() |
625 | ||
626 | Example | |
627 | ||
628 | @symbols = dl_undef_symbols() | |
629 | ||
630 | Return a list of symbol names which remain undefined after load_file(). | |
631 | Returns C<()> if not known. Don't worry if your platform does not provide | |
c2960299 AD |
632 | a mechanism for this. Most do not need it and hence do not provide it, |
633 | they just return an empty list. | |
3b35bae3 AD |
634 | |
635 | ||
636 | =item dl_install_xsub() | |
637 | ||
638 | Syntax: | |
639 | ||
640 | dl_install_xsub($perl_name, $symref [, $filename]) | |
641 | ||
642 | Create a new Perl external subroutine named $perl_name using $symref as | |
643 | a pointer to the function which implements the routine. This is simply | |
644 | a direct call to newXSUB(). Returns a reference to the installed | |
645 | function. | |
646 | ||
647 | The $filename parameter is used by Perl to identify the source file for | |
648 | the function if required by die(), caller() or the debugger. If | |
649 | $filename is not defined then "DynaLoader" will be used. | |
650 | ||
651 | ||
1fef88e7 | 652 | =item bootstrap() |
3b35bae3 AD |
653 | |
654 | Syntax: | |
655 | ||
656 | bootstrap($module) | |
657 | ||
658 | This is the normal entry point for automatic dynamic loading in Perl. | |
659 | ||
660 | It performs the following actions: | |
661 | ||
662 | =over 8 | |
663 | ||
664 | =item * | |
665 | ||
666 | locates an auto/$module directory by searching @INC | |
667 | ||
668 | =item * | |
669 | ||
670 | uses dl_findfile() to determine the filename to load | |
671 | ||
672 | =item * | |
673 | ||
674 | sets @dl_require_symbols to C<("boot_$module")> | |
675 | ||
676 | =item * | |
677 | ||
678 | executes an F<auto/$module/$module.bs> file if it exists | |
679 | (typically used to add to @dl_resolve_using any files which | |
680 | are required to load the module on the current platform) | |
681 | ||
682 | =item * | |
683 | ||
ff7f3c60 NIS |
684 | calls dl_load_flags() to determine how to load the file. |
685 | ||
686 | =item * | |
687 | ||
3b35bae3 AD |
688 | calls dl_load_file() to load the file |
689 | ||
690 | =item * | |
691 | ||
692 | calls dl_undef_symbols() and warns if any symbols are undefined | |
693 | ||
694 | =item * | |
695 | ||
696 | calls dl_find_symbol() for "boot_$module" | |
697 | ||
698 | =item * | |
699 | ||
700 | calls dl_install_xsub() to install it as "${module}::bootstrap" | |
701 | ||
702 | =item * | |
703 | ||
8e07c86e AD |
704 | calls &{"${module}::bootstrap"} to bootstrap the module (actually |
705 | it uses the function reference returned by dl_install_xsub for speed) | |
3b35bae3 AD |
706 | |
707 | =back | |
708 | ||
709 | =back | |
710 | ||
711 | ||
712 | =head1 AUTHOR | |
713 | ||
c2960299 AD |
714 | Tim Bunce, 11 August 1994. |
715 | ||
3b35bae3 AD |
716 | This interface is based on the work and comments of (in no particular |
717 | order): Larry Wall, Robert Sanders, Dean Roehrich, Jeff Okamoto, Anno | |
c2960299 | 718 | Siegel, Thomas Neumann, Paul Marquess, Charles Bailey, myself and others. |
3b35bae3 AD |
719 | |
720 | Larry Wall designed the elegant inherited bootstrap mechanism and | |
721 | implemented the first Perl 5 dynamic loader using it. | |
722 | ||
ff7f3c60 NIS |
723 | Solaris global loading added by Nick Ing-Simmons with design/coding |
724 | assistance from Tim Bunce, January 1996. | |
725 | ||
3b35bae3 | 726 | =cut |
03c9e98c GS |
727 | EOT |
728 | ||
729 | close OUT or die $!; | |
730 |