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 = "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';
75 $Is_MacOS = $^O eq 'MacOS';
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
80 @dl_librefs = (); # things we have loaded
81 @dl_modules = (); # Modules we have loaded
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";
86 # Initialise @dl_library_path with the 'standard' library path
87 # for this platform as determined by Configure
89 # push(@dl_library_path, split(' ', $Config::Config{'libpth'});
92 print OUT "push(\@dl_library_path, split(' ', ",
93 to_string($Config::Config{'libpth'}), "));\n";
97 # Add to @dl_library_path any extra directories we can gather
98 # from environment variables.
100 push(@dl_library_path, split(/,/, $ENV{LD_LIBRARY_PATH}))
101 if exists $ENV{LD_LIBRARY_PATH};
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}} ;;
111 # E.g. HP-UX supports both its native SHLIB_PATH *and* LD_LIBRARY_PATH.
112 push(@dl_library_path, split(/:/, $ENV{LD_LIBRARY_PATH}))
113 if exists $ENV{LD_LIBRARY_PATH};
116 # No prizes for guessing why we don't say 'bootstrap DynaLoader;' here.
117 boot_DynaLoader('DynaLoader') if defined(&boot_DynaLoader) &&
118 !defined(&dl_load_file);
122 print STDERR "DynaLoader.pm loaded (@INC, @dl_library_path)\n";
123 print STDERR "DynaLoader not linked into this perl\n"
124 unless defined(&boot_DynaLoader);
127 1; # End of main code
130 sub croak { require Carp; Carp::croak(@_) }
132 sub bootstrap_inherit {
134 local *isa = *{"$module\::ISA"};
135 local @isa = (@isa, 'DynaLoader');
136 # Cannot goto due to delocalization. Will report errors on a wrong line?
140 # The bootstrap function cannot be autoloaded (without complications)
141 # so we define it here:
144 # use local vars to enable $module.bs script to edit values
146 local($module) = $args[0];
151 Carp::confess("Usage: DynaLoader::bootstrap(module)");
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.
156 croak("Can't load module $module, dynamic loading not available in this perl.\n".
157 " (You may need to build a new perl executable which either supports\n".
158 " dynamic loading or has the $module module statically linked into it.)\n")
159 unless defined(&dl_load_file);
161 my @modparts = split(/::/,$module);
162 my $modfname = $modparts[-1];
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;
169 my $modpname = join(($Is_MacOS ? ':' : '/'),@modparts);
171 print STDERR "DynaLoader::bootstrap for $module ",
173 ? "(auto/$modpname/$modfname.$dl_dlext)\n" :
174 "(:auto:$modpname:$modfname.$dl_dlext)\n")
178 chop($_ = VMS::Filespec::unixpath($_)) if $Is_VMS;
182 $dir = "$_:auto:$modpname";
184 $dir = "$_/auto/$modpname";
186 next unless -d $dir; # skip over uninteresting directories
188 # check for common cases to avoid autoload of dl_findfile
189 my $try = $Is_MacOS ? "$dir:$modfname.$dl_dlext" : "$dir/$modfname.$dl_dlext";
190 last if $file = ($do_expand) ? dl_expandspec($try) : (-f $try && $try);
192 # no luck here, save dir for possible later dl_findfile search
195 # last resort, let dl_findfile have a go in all known locations
196 $file = dl_findfile(map("-L$_",@dirs,@INC), $modfname) unless $file;
198 croak("Can't locate loadable object for module $module in \@INC (\@INC contains: @INC)")
199 unless $file; # wording similar to error from 'require'
201 $file = uc($file) if $Is_VMS && $Config{d_vms_case_sensitive_symbols};
202 my $bootname = "boot_$module";
203 $bootname =~ s/\W/_/g;
204 @dl_require_symbols = ($bootname);
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.
210 $bs =~ s/(\.\w+)?(;\d*)?$/\.bs/; # look for .bs 'beside' the library
211 if (-s $bs) { # only read file if it's not empty
212 print STDERR "BS: $bs ($^O, $dlsrc)\n" if $dl_debug;
214 warn "$bs: $@\n" if $@;
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
224 my $libref = dl_load_file($file, $module->dl_load_flags) or
225 croak("Can't load '$file' for module $module: ".dl_error());
227 push(@dl_librefs,$libref); # record loaded object
229 my @unresolved = dl_undef_symbols();
232 Carp::carp("Undefined symbols present after loading $file: @unresolved\n");
235 my $boot_symbol_ref = dl_find_symbol($libref, $bootname) or
236 croak("Can't find '$bootname' symbol in $file\n");
238 my $xs = dl_install_xsub("${module}::bootstrap", $boot_symbol_ref, $file);
240 push(@dl_modules, $module); # record loaded module
242 # See comment block above
247 #sub _check_file { # private utility to handle dl_expandspec vs -f tests
249 # return $file if (!$do_expand && -f $file); # the common case
250 # return $file if ( $do_expand && ($file=dl_expandspec($file)));
255 # Let autosplit and the autoloader deal with these functions:
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.
264 my (@dirs, $dir); # which directories to search
265 my (@found); # full paths to real files we have found
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";
275 print STDERR "dl_findfile(@args)\n" if $dl_debug;
277 # accumulate directories but process files as they appear
278 arg: foreach(@args) {
279 # Special fast case: full filepath requires no search
280 if ($Is_VMS && m%[:>/\]]% && -f $_) {
281 push(@found,dl_expandspec(VMS::Filespec::vmsify($_)));
282 last arg unless wantarray;
288 last arg unless wantarray;
291 elsif (m:/: && -f $_ && !$do_expand) {
293 last arg unless wantarray;
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; }
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
309 foreach $dir (@dirs, @dl_library_path) {
311 $dir =~ s/^([^:]+)$/:$1/;
313 foreach $name (@names) {
314 my($file) = "$dir:$name";
315 print STDERR " checking in $dir for $name\n" if $dl_debug;
318 next arg; # no need to look any further
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, $_); next; }
329 # VMS: we may be using native VMS directry syntax instead of
330 # Unix emulation, so check this as well
331 if ($Is_VMS && /[:>\]]/ && -d $_) { push(@dirs, $_); next; }
333 # Only files should get this far...
334 my(@names, $name); # what filenames to look for
335 if (m:-l: ) { # convert -lname to appropriate library name
337 push(@names,"lib$_.$dl_so");
338 push(@names,"lib$_.a");
339 } else { # Umm, a bare name. Try various alternatives:
340 # these should be ordered with the most likely first
341 push(@names,"$_.$dl_ext") unless m/\.$dl_ext$/o;
342 push(@names,"$_.$dl_so") unless m/\.$dl_so$/o;
343 push(@names,"lib$_.$dl_so") unless m:/:;
344 push(@names,"$_.a") if !m/\.a$/ and $dlsrc eq "dl_dld.xs";
347 foreach $dir (@dirs, @dl_library_path) {
349 chop($dir = VMS::Filespec::unixpath($dir)) if $Is_VMS;
350 foreach $name (@names) {
351 my($file) = "$dir/$name";
352 print STDERR " checking in $dir for $name\n" if $dl_debug;
353 $file = ($do_expand) ? dl_expandspec($file) : (-f $file && $file);
354 #$file = _check_file($file);
357 next arg; # no need to look any further
364 print STDERR " dl_findfile ignored non-existent directory: $_\n" unless -d $_;
366 print STDERR "dl_findfile found: @found\n";
368 return $found[0] unless wantarray;
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.
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
385 # Must return undef if $spec is invalid or file does not exist.
387 my $file = $spec; # default output to input
389 if ($Is_VMS) { # dl_expandspec should be defined in dl_vms.xs
391 Carp::croak("dl_expandspec: should be defined in XS file!\n");
393 return undef unless -f $file;
395 print STDERR "dl_expandspec($spec) => $file\n" if $dl_debug;
399 sub dl_find_symbol_anywhere
403 foreach $libref (@dl_librefs) {
404 my $symref = dl_find_symbol($libref,$sym);
405 return $symref if $symref;
412 DynaLoader - Dynamically load C libraries into Perl code
414 dl_error(), dl_findfile(), dl_expandspec(), dl_load_file(), dl_find_symbol(), dl_find_symbol_anywhere(), dl_undef_symbols(), dl_install_xsub(), dl_load_flags(), bootstrap() - routines used by DynaLoader modules
420 @ISA = qw(... DynaLoader ...);
421 bootstrap YourPackage;
423 # optional method for 'global' loading
424 sub dl_load_flags { 0x01 }
429 This document defines a standard generic interface to the dynamic
430 linking mechanisms available on many platforms. Its primary purpose is
431 to implement automatic dynamic loading of Perl modules.
433 This document serves as both a specification for anyone wishing to
434 implement the DynaLoader for a new platform and as a guide for
435 anyone wishing to use the DynaLoader directly in an application.
437 The DynaLoader is designed to be a very simple high-level
438 interface that is sufficiently general to cover the requirements
439 of SunOS, HP-UX, NeXT, Linux, VMS and other platforms.
441 It is also hoped that the interface will cover the needs of OS/2, NT
442 etc and also allow pseudo-dynamic linking (using C<ld -A> at runtime).
444 It must be stressed that the DynaLoader, by itself, is practically
445 useless for accessing non-Perl libraries because it provides almost no
446 Perl-to-C 'glue'. There is, for example, no mechanism for calling a C
447 library function or supplying arguments. A C::DynaLib module
448 is available from CPAN sites which performs that function for some
451 DynaLoader Interface Summary
460 bootstrap($modulename) Perl
461 @filepaths = dl_findfile(@names) Perl
462 $flags = $modulename->dl_load_flags Perl
463 $symref = dl_find_symbol_anywhere($symbol) Perl
465 $libref = dl_load_file($filename, $flags) C
466 $symref = dl_find_symbol($libref, $symbol) C
467 @symbols = dl_undef_symbols() C
468 dl_install_xsub($name, $symref [, $filename]) C
469 $message = dl_error C
473 =item @dl_library_path
475 The standard/default list of directories in which dl_findfile() will
476 search for libraries etc. Directories are searched in order:
477 $dl_library_path[0], [1], ... etc
479 @dl_library_path is initialised to hold the list of 'normal' directories
480 (F</usr/lib>, etc) determined by B<Configure> (C<$Config{'libpth'}>). This should
481 ensure portability across a wide range of platforms.
483 @dl_library_path should also be initialised with any other directories
484 that can be determined from the environment at runtime (such as
485 LD_LIBRARY_PATH for SunOS).
487 After initialisation @dl_library_path can be manipulated by an
488 application using push and unshift before calling dl_findfile().
489 Unshift can be used to add directories to the front of the search order
490 either to save search time or to override libraries with the same name
491 in the 'normal' directories.
493 The load function that dl_load_file() calls may require an absolute
494 pathname. The dl_findfile() function and @dl_library_path can be
495 used to search for and return the absolute pathname for the
496 library/object that you wish to load.
498 =item @dl_resolve_using
500 A list of additional libraries or other shared objects which can be
501 used to resolve any undefined symbols that might be generated by a
502 later call to load_file().
504 This is only required on some platforms which do not handle dependent
505 libraries automatically. For example the Socket Perl extension
506 library (F<auto/Socket/Socket.so>) contains references to many socket
507 functions which need to be resolved when it's loaded. Most platforms
508 will automatically know where to find the 'dependent' library (e.g.,
509 F</usr/lib/libsocket.so>). A few platforms need to be told the
510 location of the dependent library explicitly. Use @dl_resolve_using
515 @dl_resolve_using = dl_findfile('-lsocket');
517 =item @dl_require_symbols
519 A list of one or more symbol names that are in the library/object file
520 to be dynamically loaded. This is only required on some platforms.
524 An array of the handles returned by successful calls to dl_load_file(),
525 made by bootstrap, in the order in which they were loaded.
526 Can be used with dl_find_symbol() to look for a symbol in any of
531 An array of module (package) names that have been bootstrap'ed.
537 $message = dl_error();
539 Error message text from the last failed DynaLoader function. Note
540 that, similar to errno in unix, a successful function call does not
543 Implementations should detect the error as soon as it occurs in any of
544 the other functions and save the corresponding message for later
545 retrieval. This will avoid problems on some platforms (such as SunOS)
546 where the error message is very temporary (e.g., dlerror()).
550 Internal debugging messages are enabled when $dl_debug is set true.
551 Currently setting $dl_debug only affects the Perl side of the
552 DynaLoader. These messages should help an application developer to
553 resolve any DynaLoader usage problems.
555 $dl_debug is set to C<$ENV{'PERL_DL_DEBUG'}> if defined.
557 For the DynaLoader developer/porter there is a similar debugging
558 variable added to the C code (see dlutils.c) and enabled if Perl was
559 built with the B<-DDEBUGGING> flag. This can also be set via the
560 PERL_DL_DEBUG environment variable. Set to 1 for minimal information or
567 @filepaths = dl_findfile(@names)
569 Determine the full paths (including file suffix) of one or more
570 loadable files given their generic names and optionally one or more
571 directories. Searches directories in @dl_library_path by default and
572 returns an empty list if no files were found.
574 Names can be specified in a variety of platform independent forms. Any
575 names in the form B<-lname> are converted into F<libname.*>, where F<.*> is
576 an appropriate suffix for the platform.
578 If a name does not already have a suitable prefix and/or suffix then
579 the corresponding file will be searched for by trying combinations of
580 prefix and suffix appropriate to the platform: "$name.o", "lib$name.*"
583 If any directories are included in @names they are searched before
584 @dl_library_path. Directories may be specified as B<-Ldir>. Any other
585 names are treated as filenames to be searched for.
587 Using arguments of the form C<-Ldir> and C<-lname> is recommended.
591 @dl_resolve_using = dl_findfile(qw(-L/usr/5lib -lposix));
594 =item dl_expandspec()
598 $filepath = dl_expandspec($spec)
600 Some unusual systems, such as VMS, require special filename handling in
601 order to deal with symbolic names for files (i.e., VMS's Logical Names).
603 To support these systems a dl_expandspec() function can be implemented
604 either in the F<dl_*.xs> file or code can be added to the autoloadable
605 dl_expandspec() function in F<DynaLoader.pm>. See F<DynaLoader.pm> for
612 $libref = dl_load_file($filename, $flags)
614 Dynamically load $filename, which must be the path to a shared object
615 or library. An opaque 'library reference' is returned as a handle for
616 the loaded object. Returns undef on error.
618 The $flags argument to alters dl_load_file behaviour.
621 0x01 make symbols available for linking later dl_load_file's.
622 (only known to work on Solaris 2 using dlopen(RTLD_GLOBAL))
623 (ignored under VMS; this is a normal part of image linking)
625 (On systems that provide a handle for the loaded object such as SunOS
626 and HPUX, $libref will be that handle. On other systems $libref will
627 typically be $filename or a pointer to a buffer containing $filename.
628 The application should not examine or alter $libref in any way.)
630 This is the function that does the real work. It should use the
631 current values of @dl_require_symbols and @dl_resolve_using if required.
633 SunOS: dlopen($filename)
634 HP-UX: shl_load($filename)
635 Linux: dld_create_reference(@dl_require_symbols); dld_link($filename)
636 NeXT: rld_load($filename, @dl_resolve_using)
637 VMS: lib$find_image_symbol($filename,$dl_require_symbols[0])
639 (The dlopen() function is also used by Solaris and some versions of
640 Linux, and is a common choice when providing a "wrapper" on other
641 mechanisms as is done in the OS/2 port.)
647 $flags = dl_loadflags $modulename;
649 Designed to be a method call, and to be overridden by a derived class
650 (i.e. a class which has DynaLoader in its @ISA). The definition in
651 DynaLoader itself returns 0, which produces standard behavior from
654 =item dl_find_symbol()
658 $symref = dl_find_symbol($libref, $symbol)
660 Return the address of the symbol $symbol or C<undef> if not found. If the
661 target system has separate functions to search for symbols of different
662 types then dl_find_symbol() should search for function symbols first and
665 The exact manner in which the address is returned in $symref is not
666 currently defined. The only initial requirement is that $symref can
667 be passed to, and understood by, dl_install_xsub().
669 SunOS: dlsym($libref, $symbol)
670 HP-UX: shl_findsym($libref, $symbol)
671 Linux: dld_get_func($symbol) and/or dld_get_symbol($symbol)
672 NeXT: rld_lookup("_$symbol")
673 VMS: lib$find_image_symbol($libref,$symbol)
676 =item dl_find_symbol_anywhere()
680 $symref = dl_find_symbol_anywhere($symbol)
682 Applies dl_find_symbol() to the members of @dl_librefs and returns
683 the first match found.
685 =item dl_undef_symbols()
689 @symbols = dl_undef_symbols()
691 Return a list of symbol names which remain undefined after load_file().
692 Returns C<()> if not known. Don't worry if your platform does not provide
693 a mechanism for this. Most do not need it and hence do not provide it,
694 they just return an empty list.
697 =item dl_install_xsub()
701 dl_install_xsub($perl_name, $symref [, $filename])
703 Create a new Perl external subroutine named $perl_name using $symref as
704 a pointer to the function which implements the routine. This is simply
705 a direct call to newXSUB(). Returns a reference to the installed
708 The $filename parameter is used by Perl to identify the source file for
709 the function if required by die(), caller() or the debugger. If
710 $filename is not defined then "DynaLoader" will be used.
719 This is the normal entry point for automatic dynamic loading in Perl.
721 It performs the following actions:
727 locates an auto/$module directory by searching @INC
731 uses dl_findfile() to determine the filename to load
735 sets @dl_require_symbols to C<("boot_$module")>
739 executes an F<auto/$module/$module.bs> file if it exists
740 (typically used to add to @dl_resolve_using any files which
741 are required to load the module on the current platform)
745 calls dl_load_flags() to determine how to load the file.
749 calls dl_load_file() to load the file
753 calls dl_undef_symbols() and warns if any symbols are undefined
757 calls dl_find_symbol() for "boot_$module"
761 calls dl_install_xsub() to install it as "${module}::bootstrap"
765 calls &{"${module}::bootstrap"} to bootstrap the module (actually
766 it uses the function reference returned by dl_install_xsub for speed)
775 Tim Bunce, 11 August 1994.
777 This interface is based on the work and comments of (in no particular
778 order): Larry Wall, Robert Sanders, Dean Roehrich, Jeff Okamoto, Anno
779 Siegel, Thomas Neumann, Paul Marquess, Charles Bailey, myself and others.
781 Larry Wall designed the elegant inherited bootstrap mechanism and
782 implemented the first Perl 5 dynamic loader using it.
784 Solaris global loading added by Nick Ing-Simmons with design/coding
785 assistance from Tim Bunce, January 1996.