6 $value =~ s/\\/\\\\'/g;
11 unlink "DynaLoader.pm" if -f "DynaLoader.pm";
12 open OUT, ">DynaLoader.pm" or die $!;
15 # Generated from DynaLoader.pm.PL (resolved %Config::Config values)
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
24 # (Quote from Tolkien sugested by Anno Siegel.)
26 # See pod text at end of file for documentation.
27 # See also ext/DynaLoader/README in source tree for other information.
29 # Tim.Bunce@ig.co.uk, August 1994
31 $VERSION = $VERSION = "1.03"; # avoid typo warning
34 *AUTOLOAD = \&AutoLoader::AUTOLOAD;
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;
44 # enable debug/trace messages from DynaLoader perl code
45 $dl_debug = $ENV{PERL_DL_DEBUG} || 0 unless defined $dl_debug;
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))
51 # (ignored under VMS; effect is built-in to image linking)
53 # This is called as a class method $module->dl_load_flags. The
54 # definition here will be inherited and result on "default" loading
55 # behaviour unless a sub-class of DynaLoader defines its own version.
58 sub dl_load_flags { 0x00 }
61 # = @Config::Config{'dlext', 'dlsrc'};
64 print OUT " (\$dl_dlext, \$dlsrc) = (",
65 to_string($Config::Config{'dlext'}), ",",
66 to_string($Config::Config{'dlsrc'}), ")\n;" ;
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.
74 $do_expand = $Is_VMS = $^O eq 'VMS';
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
79 @dl_librefs = (); # things we have loaded
80 @dl_modules = (); # Modules we have loaded
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";
85 # Initialise @dl_library_path with the 'standard' library path
86 # for this platform as determined by Configure
88 # push(@dl_library_path, split(' ', $Config::Config{'libpth'});
91 print OUT "push(\@dl_library_path, split(' ', ",
92 to_string($Config::Config{'libpth'}), "));\n";
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};
103 # No prizes for guessing why we don't say 'bootstrap DynaLoader;' here.
104 boot_DynaLoader('DynaLoader') if defined(&boot_DynaLoader) &&
105 !defined(&dl_load_file);
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);
114 1; # End of main code
117 sub croak { require Carp; Carp::croak(@_) }
119 # The bootstrap function cannot be autoloaded (without complications)
120 # so we define it here:
123 # use local vars to enable $module.bs script to edit values
125 local($module) = $args[0];
130 Carp::confess("Usage: DynaLoader::bootstrap(module)");
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.
135 croak("Can't load module $module, dynamic loading not available in this perl.\n".
136 " (You may need to build a new perl executable which either supports\n".
137 " dynamic loading or has the $module module statically linked into it.)\n")
138 unless defined(&dl_load_file);
140 my @modparts = split(/::/,$module);
141 my $modfname = $modparts[-1];
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;
148 my $modpname = join('/',@modparts);
150 print STDERR "DynaLoader::bootstrap for $module ",
151 "(auto/$modpname/$modfname.$dl_dlext)\n" if $dl_debug;
154 chop($_ = VMS::Filespec::unixpath($_)) if $Is_VMS;
155 my $dir = "$_/auto/$modpname";
156 next unless -d $dir; # skip over uninteresting directories
158 # check for common cases to avoid autoload of dl_findfile
159 my $try = "$dir/$modfname.$dl_dlext";
160 last if $file = ($do_expand) ? dl_expandspec($try) : (-f $try && $try);
162 # no luck here, save dir for possible later dl_findfile search
165 # last resort, let dl_findfile have a go in all known locations
166 $file = dl_findfile(map("-L$_",@dirs,@INC), $modfname) unless $file;
168 croak("Can't locate loadable object for module $module in \@INC (\@INC contains: @INC)")
169 unless $file; # wording similar to error from 'require'
171 my $bootname = "boot_$module";
172 $bootname =~ s/\W/_/g;
173 @dl_require_symbols = ($bootname);
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.
179 $bs =~ s/(\.\w+)?$/\.bs/; # look for .bs 'beside' the library
180 if (-s $bs) { # only read file if it's not empty
181 print STDERR "BS: $bs ($^O, $dlsrc)\n" if $dl_debug;
183 warn "$bs: $@\n" if $@;
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
193 my $libref = dl_load_file($file, $module->dl_load_flags) or
194 croak("Can't load '$file' for module $module: ".dl_error()."\n");
196 push(@dl_librefs,$libref); # record loaded object
198 my @unresolved = dl_undef_symbols();
201 Carp::carp("Undefined symbols present after loading $file: @unresolved\n");
204 my $boot_symbol_ref = dl_find_symbol($libref, $bootname) or
205 croak("Can't find '$bootname' symbol in $file\n");
207 my $xs = dl_install_xsub("${module}::bootstrap", $boot_symbol_ref, $file);
209 push(@dl_modules, $module); # record loaded module
211 # See comment block above
216 #sub _check_file { # private utility to handle dl_expandspec vs -f tests
218 # return $file if (!$do_expand && -f $file); # the common case
219 # return $file if ( $do_expand && ($file=dl_expandspec($file)));
224 # Let autosplit and the autoloader deal with these functions:
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.
233 my (@dirs, $dir); # which directories to search
234 my (@found); # full paths to real files we have found
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";
244 print STDERR "dl_findfile(@args)\n" if $dl_debug;
246 # accumulate directories but process files as they appear
247 arg: foreach(@args) {
248 # Special fast case: full filepath requires no search
249 if ($Is_VMS && m%[:>/\]]% && -f $_) {
250 push(@found,dl_expandspec(VMS::Filespec::vmsify($_)));
251 last arg unless wantarray;
254 elsif (m:/: && -f $_ && !$do_expand) {
256 last arg unless wantarray;
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; }
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, $_); next; }
268 # VMS: we may be using native VMS directry syntax instead of
269 # Unix emulation, so check this as well
270 if ($Is_VMS && /[:>\]]/ && -d $_) { push(@dirs, $_); next; }
272 # Only files should get this far...
273 my(@names, $name); # what filenames to look for
274 if (m:-l: ) { # convert -lname to appropriate library name
276 push(@names,"lib$_.$dl_so");
277 push(@names,"lib$_.a");
278 } else { # Umm, a bare name. Try various alternatives:
279 # these should be ordered with the most likely first
280 push(@names,"$_.$dl_ext") unless m/\.$dl_ext$/o;
281 push(@names,"$_.$dl_so") unless m/\.$dl_so$/o;
282 push(@names,"lib$_.$dl_so") unless m:/:;
283 push(@names,"$_.a") if !m/\.a$/ and $dlsrc eq "dl_dld.xs";
286 foreach $dir (@dirs, @dl_library_path) {
288 chop($dir = VMS::Filespec::unixpath($dir)) if $Is_VMS;
289 foreach $name (@names) {
290 my($file) = "$dir/$name";
291 print STDERR " checking in $dir for $name\n" if $dl_debug;
292 $file = ($do_expand) ? dl_expandspec($file) : (-f $file && $file);
293 #$file = _check_file($file);
296 next arg; # no need to look any further
303 print STDERR " dl_findfile ignored non-existent directory: $_\n" unless -d $_;
305 print STDERR "dl_findfile found: @found\n";
307 return $found[0] unless wantarray;
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.
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
324 # Must return undef if $spec is invalid or file does not exist.
326 my $file = $spec; # default output to input
328 if ($Is_VMS) { # dl_expandspec should be defined in dl_vms.xs
330 Carp::croak("dl_expandspec: should be defined in XS file!\n");
332 return undef unless -f $file;
334 print STDERR "dl_expandspec($spec) => $file\n" if $dl_debug;
338 sub dl_find_symbol_anywhere
342 foreach $libref (@dl_librefs) {
343 my $symref = dl_find_symbol($libref,$sym);
344 return $symref if $symref;
351 DynaLoader - Dynamically load C libraries into Perl code
353 dl_error(), dl_findfile(), dl_expandspec(), dl_load_file(), dl_find_symbol(), dl_find_symbol_anywhere(), dl_undef_symbols(), dl_install_xsub(), dl_load_flags(), bootstrap() - routines used by DynaLoader modules
359 @ISA = qw(... DynaLoader ...);
360 bootstrap YourPackage;
362 # optional method for 'global' loading
363 sub dl_load_flags { 0x01 }
368 This document defines a standard generic interface to the dynamic
369 linking mechanisms available on many platforms. Its primary purpose is
370 to implement automatic dynamic loading of Perl modules.
372 This document serves as both a specification for anyone wishing to
373 implement the DynaLoader for a new platform and as a guide for
374 anyone wishing to use the DynaLoader directly in an application.
376 The DynaLoader is designed to be a very simple high-level
377 interface that is sufficiently general to cover the requirements
378 of SunOS, HP-UX, NeXT, Linux, VMS and other platforms.
380 It is also hoped that the interface will cover the needs of OS/2, NT
381 etc and also allow pseudo-dynamic linking (using C<ld -A> at runtime).
383 It must be stressed that the DynaLoader, by itself, is practically
384 useless for accessing non-Perl libraries because it provides almost no
385 Perl-to-C 'glue'. There is, for example, no mechanism for calling a C
386 library function or supplying arguments. A C::DynaLib module
387 is available from CPAN sites which performs that function for some
390 DynaLoader Interface Summary
399 bootstrap($modulename) Perl
400 @filepaths = dl_findfile(@names) Perl
401 $flags = $modulename->dl_load_flags Perl
402 $symref = dl_find_symbol_anywhere($symbol) Perl
404 $libref = dl_load_file($filename, $flags) C
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
412 =item @dl_library_path
414 The standard/default list of directories in which dl_findfile() will
415 search for libraries etc. Directories are searched in order:
416 $dl_library_path[0], [1], ... etc
418 @dl_library_path is initialised to hold the list of 'normal' directories
419 (F</usr/lib>, etc) determined by B<Configure> (C<$Config{'libpth'}>). This should
420 ensure portability across a wide range of platforms.
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).
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.
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.
437 =item @dl_resolve_using
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().
443 This is only required on some platforms which do not handle dependent
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
454 @dl_resolve_using = dl_findfile('-lsocket');
456 =item @dl_require_symbols
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.
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
470 An array of module (package) names that have been bootstrap'ed.
476 $message = dl_error();
478 Error message text from the last failed DynaLoader function. Note
479 that, similar to errno in unix, a successful function call does not
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()).
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.
494 $dl_debug is set to C<$ENV{'PERL_DL_DEBUG'}> if defined.
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
506 @filepaths = dl_findfile(@names)
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.
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.
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.*"
522 If any directories are included in @names they are searched before
523 @dl_library_path. Directories may be specified as B<-Ldir>. Any other
524 names are treated as filenames to be searched for.
526 Using arguments of the form C<-Ldir> and C<-lname> is recommended.
530 @dl_resolve_using = dl_findfile(qw(-L/usr/5lib -lposix));
533 =item dl_expandspec()
537 $filepath = dl_expandspec($spec)
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).
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
544 dl_expandspec() function in F<DynaLoader.pm>. See F<DynaLoader.pm> for
551 $libref = dl_load_file($filename, $flags)
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.
557 The $flags argument to alters dl_load_file behaviour.
560 0x01 make symbols available for linking later dl_load_file's.
561 (only known to work on Solaris 2 using dlopen(RTLD_GLOBAL))
562 (ignored under VMS; this is a normal part of image linking)
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 $libref in any way.)
569 This is the function that does the real work. It should use the
570 current values of @dl_require_symbols and @dl_resolve_using if required.
572 SunOS: dlopen($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])
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.)
586 $flags = dl_loadflags $modulename;
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
593 =item dl_find_symbol()
597 $symref = dl_find_symbol($libref, $symbol)
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
604 The exact manner in which the address is returned in $symref is not
605 currently defined. The only initial requirement is that $symref can
606 be passed to, and understood by, dl_install_xsub().
608 SunOS: dlsym($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)
615 =item dl_find_symbol_anywhere()
619 $symref = dl_find_symbol_anywhere($symbol)
621 Applies dl_find_symbol() to the members of @dl_librefs and returns
622 the first match found.
624 =item dl_undef_symbols()
628 @symbols = dl_undef_symbols()
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
632 a mechanism for this. Most do not need it and hence do not provide it,
633 they just return an empty list.
636 =item dl_install_xsub()
640 dl_install_xsub($perl_name, $symref [, $filename])
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
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 $filename is not defined then "DynaLoader" will be used.
658 This is the normal entry point for automatic dynamic loading in Perl.
660 It performs the following actions:
666 locates an auto/$module directory by searching @INC
670 uses dl_findfile() to determine the filename to load
674 sets @dl_require_symbols to C<("boot_$module")>
678 executes an F<auto/$module/$module.bs> file if it exists
679 (typically used to add to @dl_resolve_using any files which
680 are required to load the module on the current platform)
684 calls dl_load_flags() to determine how to load the file.
688 calls dl_load_file() to load the file
692 calls dl_undef_symbols() and warns if any symbols are undefined
696 calls dl_find_symbol() for "boot_$module"
700 calls dl_install_xsub() to install it as "${module}::bootstrap"
704 calls &{"${module}::bootstrap"} to bootstrap the module (actually
705 it uses the function reference returned by dl_install_xsub for speed)
714 Tim Bunce, 11 August 1994.
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
718 Siegel, Thomas Neumann, Paul Marquess, Charles Bailey, myself and others.
720 Larry Wall designed the elegant inherited bootstrap mechanism and
721 implemented the first Perl 5 dynamic loader using it.
723 Solaris global loading added by Nick Ing-Simmons with design/coding
724 assistance from Tim Bunce, January 1996.