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 my $bootname = "boot_$module";
202 $bootname =~ s/\W/_/g;
203 @dl_require_symbols = ($bootname);
205 # Execute optional '.bootstrap' perl script for this module.
206 # The .bs file can be used to configure @dl_resolve_using etc to
207 # match the needs of the individual module on this architecture.
209 $bs =~ s/(\.\w+)?(;\d*)?$/\.bs/; # look for .bs 'beside' the library
210 if (-s $bs) { # only read file if it's not empty
211 print STDERR "BS: $bs ($^O, $dlsrc)\n" if $dl_debug;
213 warn "$bs: $@\n" if $@;
216 # Many dynamic extension loading problems will appear to come from
217 # this section of code: XYZ failed at line 123 of DynaLoader.pm.
218 # Often these errors are actually occurring in the initialisation
219 # C code of the extension XS file. Perl reports the error as being
220 # in this perl code simply because this was the last perl code
223 my $libref = dl_load_file($file, $module->dl_load_flags) or
224 croak("Can't load '$file' for module $module: ".dl_error());
226 push(@dl_librefs,$libref); # record loaded object
228 my @unresolved = dl_undef_symbols();
231 Carp::carp("Undefined symbols present after loading $file: @unresolved\n");
234 my $boot_symbol_ref = dl_find_symbol($libref, $bootname) or
235 croak("Can't find '$bootname' symbol in $file\n");
237 my $xs = dl_install_xsub("${module}::bootstrap", $boot_symbol_ref, $file);
239 push(@dl_modules, $module); # record loaded module
241 # See comment block above
246 #sub _check_file { # private utility to handle dl_expandspec vs -f tests
248 # return $file if (!$do_expand && -f $file); # the common case
249 # return $file if ( $do_expand && ($file=dl_expandspec($file)));
254 # Let autosplit and the autoloader deal with these functions:
259 # Read ext/DynaLoader/DynaLoader.doc for detailed information.
260 # This function does not automatically consider the architecture
261 # or the perl library auto directories.
263 my (@dirs, $dir); # which directories to search
264 my (@found); # full paths to real files we have found
267 print OUT ' my $dl_ext= ' . to_string($Config::Config{'dlext'}) .
268 "; # \$Config::Config{'dlext'} suffix for perl extensions\n";
269 print OUT ' my $dl_so = ' . to_string($Config::Config{'so'}) .
270 "; # \$Config::Config{'so'} suffix for shared libraries\n";
274 print STDERR "dl_findfile(@args)\n" if $dl_debug;
276 # accumulate directories but process files as they appear
277 arg: foreach(@args) {
278 # Special fast case: full filepath requires no search
279 if ($Is_VMS && m%[:>/\]]% && -f $_) {
280 push(@found,dl_expandspec(VMS::Filespec::vmsify($_)));
281 last arg unless wantarray;
287 last arg unless wantarray;
290 elsif (m:/: && -f $_ && !$do_expand) {
292 last arg unless wantarray;
296 # Deal with directories first:
297 # Using a -L prefix is the preferred option (faster and more robust)
298 if (m:^-L:) { s/^-L//; push(@dirs, $_); next; }
301 # Otherwise we try to try to spot directories by a heuristic
302 # (this is a more complicated issue than it first appears)
303 if (m/:/ && -d $_) { push(@dirs, $_); next; }
304 # Only files should get this far...
305 my(@names, $name); # what filenames to look for
308 foreach $dir (@dirs, @dl_library_path) {
310 $dir =~ s/^([^:]+)$/:$1/;
312 foreach $name (@names) {
313 my($file) = "$dir:$name";
314 print STDERR " checking in $dir for $name\n" if $dl_debug;
317 next arg; # no need to look any further
324 # Otherwise we try to try to spot directories by a heuristic
325 # (this is a more complicated issue than it first appears)
326 if (m:/: && -d $_) { push(@dirs, $_); next; }
328 # VMS: we may be using native VMS directry syntax instead of
329 # Unix emulation, so check this as well
330 if ($Is_VMS && /[:>\]]/ && -d $_) { push(@dirs, $_); next; }
332 # Only files should get this far...
333 my(@names, $name); # what filenames to look for
334 if (m:-l: ) { # convert -lname to appropriate library name
336 push(@names,"lib$_.$dl_so");
337 push(@names,"lib$_.a");
338 } else { # Umm, a bare name. Try various alternatives:
339 # these should be ordered with the most likely first
340 push(@names,"$_.$dl_ext") unless m/\.$dl_ext$/o;
341 push(@names,"$_.$dl_so") unless m/\.$dl_so$/o;
342 push(@names,"lib$_.$dl_so") unless m:/:;
343 push(@names,"$_.a") if !m/\.a$/ and $dlsrc eq "dl_dld.xs";
346 foreach $dir (@dirs, @dl_library_path) {
348 chop($dir = VMS::Filespec::unixpath($dir)) if $Is_VMS;
349 foreach $name (@names) {
350 my($file) = "$dir/$name";
351 print STDERR " checking in $dir for $name\n" if $dl_debug;
352 $file = ($do_expand) ? dl_expandspec($file) : (-f $file && $file);
353 #$file = _check_file($file);
356 next arg; # no need to look any further
363 print STDERR " dl_findfile ignored non-existent directory: $_\n" unless -d $_;
365 print STDERR "dl_findfile found: @found\n";
367 return $found[0] unless wantarray;
374 # Optional function invoked if DynaLoader.pm sets $do_expand.
375 # Most systems do not require or use this function.
376 # Some systems may implement it in the dl_*.xs file in which case
377 # this autoload version will not be called but is harmless.
379 # This function is designed to deal with systems which treat some
380 # 'filenames' in a special way. For example VMS 'Logical Names'
381 # (something like unix environment variables - but different).
382 # This function should recognise such names and expand them into
384 # Must return undef if $spec is invalid or file does not exist.
386 my $file = $spec; # default output to input
388 if ($Is_VMS) { # dl_expandspec should be defined in dl_vms.xs
390 Carp::croak("dl_expandspec: should be defined in XS file!\n");
392 return undef unless -f $file;
394 print STDERR "dl_expandspec($spec) => $file\n" if $dl_debug;
398 sub dl_find_symbol_anywhere
402 foreach $libref (@dl_librefs) {
403 my $symref = dl_find_symbol($libref,$sym);
404 return $symref if $symref;
411 DynaLoader - Dynamically load C libraries into Perl code
413 dl_error(), dl_findfile(), dl_expandspec(), dl_load_file(), dl_find_symbol(), dl_find_symbol_anywhere(), dl_undef_symbols(), dl_install_xsub(), dl_load_flags(), bootstrap() - routines used by DynaLoader modules
419 @ISA = qw(... DynaLoader ...);
420 bootstrap YourPackage;
422 # optional method for 'global' loading
423 sub dl_load_flags { 0x01 }
428 This document defines a standard generic interface to the dynamic
429 linking mechanisms available on many platforms. Its primary purpose is
430 to implement automatic dynamic loading of Perl modules.
432 This document serves as both a specification for anyone wishing to
433 implement the DynaLoader for a new platform and as a guide for
434 anyone wishing to use the DynaLoader directly in an application.
436 The DynaLoader is designed to be a very simple high-level
437 interface that is sufficiently general to cover the requirements
438 of SunOS, HP-UX, NeXT, Linux, VMS and other platforms.
440 It is also hoped that the interface will cover the needs of OS/2, NT
441 etc and also allow pseudo-dynamic linking (using C<ld -A> at runtime).
443 It must be stressed that the DynaLoader, by itself, is practically
444 useless for accessing non-Perl libraries because it provides almost no
445 Perl-to-C 'glue'. There is, for example, no mechanism for calling a C
446 library function or supplying arguments. A C::DynaLib module
447 is available from CPAN sites which performs that function for some
450 DynaLoader Interface Summary
459 bootstrap($modulename) Perl
460 @filepaths = dl_findfile(@names) Perl
461 $flags = $modulename->dl_load_flags Perl
462 $symref = dl_find_symbol_anywhere($symbol) Perl
464 $libref = dl_load_file($filename, $flags) C
465 $symref = dl_find_symbol($libref, $symbol) C
466 @symbols = dl_undef_symbols() C
467 dl_install_xsub($name, $symref [, $filename]) C
468 $message = dl_error C
472 =item @dl_library_path
474 The standard/default list of directories in which dl_findfile() will
475 search for libraries etc. Directories are searched in order:
476 $dl_library_path[0], [1], ... etc
478 @dl_library_path is initialised to hold the list of 'normal' directories
479 (F</usr/lib>, etc) determined by B<Configure> (C<$Config{'libpth'}>). This should
480 ensure portability across a wide range of platforms.
482 @dl_library_path should also be initialised with any other directories
483 that can be determined from the environment at runtime (such as
484 LD_LIBRARY_PATH for SunOS).
486 After initialisation @dl_library_path can be manipulated by an
487 application using push and unshift before calling dl_findfile().
488 Unshift can be used to add directories to the front of the search order
489 either to save search time or to override libraries with the same name
490 in the 'normal' directories.
492 The load function that dl_load_file() calls may require an absolute
493 pathname. The dl_findfile() function and @dl_library_path can be
494 used to search for and return the absolute pathname for the
495 library/object that you wish to load.
497 =item @dl_resolve_using
499 A list of additional libraries or other shared objects which can be
500 used to resolve any undefined symbols that might be generated by a
501 later call to load_file().
503 This is only required on some platforms which do not handle dependent
504 libraries automatically. For example the Socket Perl extension
505 library (F<auto/Socket/Socket.so>) contains references to many socket
506 functions which need to be resolved when it's loaded. Most platforms
507 will automatically know where to find the 'dependent' library (e.g.,
508 F</usr/lib/libsocket.so>). A few platforms need to be told the
509 location of the dependent library explicitly. Use @dl_resolve_using
514 @dl_resolve_using = dl_findfile('-lsocket');
516 =item @dl_require_symbols
518 A list of one or more symbol names that are in the library/object file
519 to be dynamically loaded. This is only required on some platforms.
523 An array of the handles returned by successful calls to dl_load_file(),
524 made by bootstrap, in the order in which they were loaded.
525 Can be used with dl_find_symbol() to look for a symbol in any of
530 An array of module (package) names that have been bootstrap'ed.
536 $message = dl_error();
538 Error message text from the last failed DynaLoader function. Note
539 that, similar to errno in unix, a successful function call does not
542 Implementations should detect the error as soon as it occurs in any of
543 the other functions and save the corresponding message for later
544 retrieval. This will avoid problems on some platforms (such as SunOS)
545 where the error message is very temporary (e.g., dlerror()).
549 Internal debugging messages are enabled when $dl_debug is set true.
550 Currently setting $dl_debug only affects the Perl side of the
551 DynaLoader. These messages should help an application developer to
552 resolve any DynaLoader usage problems.
554 $dl_debug is set to C<$ENV{'PERL_DL_DEBUG'}> if defined.
556 For the DynaLoader developer/porter there is a similar debugging
557 variable added to the C code (see dlutils.c) and enabled if Perl was
558 built with the B<-DDEBUGGING> flag. This can also be set via the
559 PERL_DL_DEBUG environment variable. Set to 1 for minimal information or
566 @filepaths = dl_findfile(@names)
568 Determine the full paths (including file suffix) of one or more
569 loadable files given their generic names and optionally one or more
570 directories. Searches directories in @dl_library_path by default and
571 returns an empty list if no files were found.
573 Names can be specified in a variety of platform independent forms. Any
574 names in the form B<-lname> are converted into F<libname.*>, where F<.*> is
575 an appropriate suffix for the platform.
577 If a name does not already have a suitable prefix and/or suffix then
578 the corresponding file will be searched for by trying combinations of
579 prefix and suffix appropriate to the platform: "$name.o", "lib$name.*"
582 If any directories are included in @names they are searched before
583 @dl_library_path. Directories may be specified as B<-Ldir>. Any other
584 names are treated as filenames to be searched for.
586 Using arguments of the form C<-Ldir> and C<-lname> is recommended.
590 @dl_resolve_using = dl_findfile(qw(-L/usr/5lib -lposix));
593 =item dl_expandspec()
597 $filepath = dl_expandspec($spec)
599 Some unusual systems, such as VMS, require special filename handling in
600 order to deal with symbolic names for files (i.e., VMS's Logical Names).
602 To support these systems a dl_expandspec() function can be implemented
603 either in the F<dl_*.xs> file or code can be added to the autoloadable
604 dl_expandspec() function in F<DynaLoader.pm>. See F<DynaLoader.pm> for
611 $libref = dl_load_file($filename, $flags)
613 Dynamically load $filename, which must be the path to a shared object
614 or library. An opaque 'library reference' is returned as a handle for
615 the loaded object. Returns undef on error.
617 The $flags argument to alters dl_load_file behaviour.
620 0x01 make symbols available for linking later dl_load_file's.
621 (only known to work on Solaris 2 using dlopen(RTLD_GLOBAL))
622 (ignored under VMS; this is a normal part of image linking)
624 (On systems that provide a handle for the loaded object such as SunOS
625 and HPUX, $libref will be that handle. On other systems $libref will
626 typically be $filename or a pointer to a buffer containing $filename.
627 The application should not examine or alter $libref in any way.)
629 This is the function that does the real work. It should use the
630 current values of @dl_require_symbols and @dl_resolve_using if required.
632 SunOS: dlopen($filename)
633 HP-UX: shl_load($filename)
634 Linux: dld_create_reference(@dl_require_symbols); dld_link($filename)
635 NeXT: rld_load($filename, @dl_resolve_using)
636 VMS: lib$find_image_symbol($filename,$dl_require_symbols[0])
638 (The dlopen() function is also used by Solaris and some versions of
639 Linux, and is a common choice when providing a "wrapper" on other
640 mechanisms as is done in the OS/2 port.)
646 $flags = dl_loadflags $modulename;
648 Designed to be a method call, and to be overridden by a derived class
649 (i.e. a class which has DynaLoader in its @ISA). The definition in
650 DynaLoader itself returns 0, which produces standard behavior from
653 =item dl_find_symbol()
657 $symref = dl_find_symbol($libref, $symbol)
659 Return the address of the symbol $symbol or C<undef> if not found. If the
660 target system has separate functions to search for symbols of different
661 types then dl_find_symbol() should search for function symbols first and
664 The exact manner in which the address is returned in $symref is not
665 currently defined. The only initial requirement is that $symref can
666 be passed to, and understood by, dl_install_xsub().
668 SunOS: dlsym($libref, $symbol)
669 HP-UX: shl_findsym($libref, $symbol)
670 Linux: dld_get_func($symbol) and/or dld_get_symbol($symbol)
671 NeXT: rld_lookup("_$symbol")
672 VMS: lib$find_image_symbol($libref,$symbol)
675 =item dl_find_symbol_anywhere()
679 $symref = dl_find_symbol_anywhere($symbol)
681 Applies dl_find_symbol() to the members of @dl_librefs and returns
682 the first match found.
684 =item dl_undef_symbols()
688 @symbols = dl_undef_symbols()
690 Return a list of symbol names which remain undefined after load_file().
691 Returns C<()> if not known. Don't worry if your platform does not provide
692 a mechanism for this. Most do not need it and hence do not provide it,
693 they just return an empty list.
696 =item dl_install_xsub()
700 dl_install_xsub($perl_name, $symref [, $filename])
702 Create a new Perl external subroutine named $perl_name using $symref as
703 a pointer to the function which implements the routine. This is simply
704 a direct call to newXSUB(). Returns a reference to the installed
707 The $filename parameter is used by Perl to identify the source file for
708 the function if required by die(), caller() or the debugger. If
709 $filename is not defined then "DynaLoader" will be used.
718 This is the normal entry point for automatic dynamic loading in Perl.
720 It performs the following actions:
726 locates an auto/$module directory by searching @INC
730 uses dl_findfile() to determine the filename to load
734 sets @dl_require_symbols to C<("boot_$module")>
738 executes an F<auto/$module/$module.bs> file if it exists
739 (typically used to add to @dl_resolve_using any files which
740 are required to load the module on the current platform)
744 calls dl_load_flags() to determine how to load the file.
748 calls dl_load_file() to load the file
752 calls dl_undef_symbols() and warns if any symbols are undefined
756 calls dl_find_symbol() for "boot_$module"
760 calls dl_install_xsub() to install it as "${module}::bootstrap"
764 calls &{"${module}::bootstrap"} to bootstrap the module (actually
765 it uses the function reference returned by dl_install_xsub for speed)
774 Tim Bunce, 11 August 1994.
776 This interface is based on the work and comments of (in no particular
777 order): Larry Wall, Robert Sanders, Dean Roehrich, Jeff Okamoto, Anno
778 Siegel, Thomas Neumann, Paul Marquess, Charles Bailey, myself and others.
780 Larry Wall designed the elegant inherited bootstrap mechanism and
781 implemented the first Perl 5 dynamic loader using it.
783 Solaris global loading added by Nick Ing-Simmons with design/coding
784 assistance from Tim Bunce, January 1996.