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';
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 # The bootstrap function cannot be autoloaded (without complications)
133 # so we define it here:
136 # use local vars to enable $module.bs script to edit values
138 local($module) = $args[0];
143 Carp::confess("Usage: DynaLoader::bootstrap(module)");
146 # A common error on platforms which don't support dynamic loading.
147 # Since it's fatal and potentially confusing we give a detailed message.
148 croak("Can't load module $module, dynamic loading not available in this perl.\n".
149 " (You may need to build a new perl executable which either supports\n".
150 " dynamic loading or has the $module module statically linked into it.)\n")
151 unless defined(&dl_load_file);
153 my @modparts = split(/::/,$module);
154 my $modfname = $modparts[-1];
156 # Some systems have restrictions on files names for DLL's etc.
157 # mod2fname returns appropriate file base name (typically truncated)
158 # It may also edit @modparts if required.
159 $modfname = &mod2fname(\@modparts) if defined &mod2fname;
161 my $modpname = join(($Is_MacOS ? ':' : '/'),@modparts);
163 print STDERR "DynaLoader::bootstrap for $module ",
165 ? "(auto/$modpname/$modfname.$dl_dlext)\n" :
166 "(:auto:$modpname:$modfname.$dl_dlext)\n")
170 chop($_ = VMS::Filespec::unixpath($_)) if $Is_VMS;
174 $dir = "$_:auto:$modpname";
176 $dir = "$_/auto/$modpname";
178 next unless -d $dir; # skip over uninteresting directories
180 # check for common cases to avoid autoload of dl_findfile
181 my $try = $Is_MacOS ? "$dir:$modfname.$dl_dlext" : "$dir/$modfname.$dl_dlext";
182 last if $file = ($do_expand) ? dl_expandspec($try) : (-f $try && $try);
184 # no luck here, save dir for possible later dl_findfile search
187 # last resort, let dl_findfile have a go in all known locations
188 $file = dl_findfile(map("-L$_",@dirs,@INC), $modfname) unless $file;
190 croak("Can't locate loadable object for module $module in \@INC (\@INC contains: @INC)")
191 unless $file; # wording similar to error from 'require'
193 my $bootname = "boot_$module";
194 $bootname =~ s/\W/_/g;
195 @dl_require_symbols = ($bootname);
197 # Execute optional '.bootstrap' perl script for this module.
198 # The .bs file can be used to configure @dl_resolve_using etc to
199 # match the needs of the individual module on this architecture.
201 $bs =~ s/(\.\w+)?(;\d*)?$/\.bs/; # look for .bs 'beside' the library
202 if (-s $bs) { # only read file if it's not empty
203 print STDERR "BS: $bs ($^O, $dlsrc)\n" if $dl_debug;
205 warn "$bs: $@\n" if $@;
208 # Many dynamic extension loading problems will appear to come from
209 # this section of code: XYZ failed at line 123 of DynaLoader.pm.
210 # Often these errors are actually occurring in the initialisation
211 # C code of the extension XS file. Perl reports the error as being
212 # in this perl code simply because this was the last perl code
215 my $libref = dl_load_file($file, $module->dl_load_flags) or
216 croak("Can't load '$file' for module $module: ".dl_error());
218 push(@dl_librefs,$libref); # record loaded object
220 my @unresolved = dl_undef_symbols();
223 Carp::carp("Undefined symbols present after loading $file: @unresolved\n");
226 my $boot_symbol_ref = dl_find_symbol($libref, $bootname) or
227 croak("Can't find '$bootname' symbol in $file\n");
229 my $xs = dl_install_xsub("${module}::bootstrap", $boot_symbol_ref, $file);
231 push(@dl_modules, $module); # record loaded module
233 # See comment block above
238 #sub _check_file { # private utility to handle dl_expandspec vs -f tests
240 # return $file if (!$do_expand && -f $file); # the common case
241 # return $file if ( $do_expand && ($file=dl_expandspec($file)));
246 # Let autosplit and the autoloader deal with these functions:
251 # Read ext/DynaLoader/DynaLoader.doc for detailed information.
252 # This function does not automatically consider the architecture
253 # or the perl library auto directories.
255 my (@dirs, $dir); # which directories to search
256 my (@found); # full paths to real files we have found
259 print OUT ' my $dl_ext= ' . to_string($Config::Config{'dlext'}) .
260 "; # \$Config::Config{'dlext'} suffix for perl extensions\n";
261 print OUT ' my $dl_so = ' . to_string($Config::Config{'so'}) .
262 "; # \$Config::Config{'so'} suffix for shared libraries\n";
266 print STDERR "dl_findfile(@args)\n" if $dl_debug;
268 # accumulate directories but process files as they appear
269 arg: foreach(@args) {
270 # Special fast case: full filepath requires no search
271 if ($Is_VMS && m%[:>/\]]% && -f $_) {
272 push(@found,dl_expandspec(VMS::Filespec::vmsify($_)));
273 last arg unless wantarray;
279 last arg unless wantarray;
282 elsif (m:/: && -f $_ && !$do_expand) {
284 last arg unless wantarray;
288 # Deal with directories first:
289 # Using a -L prefix is the preferred option (faster and more robust)
290 if (m:^-L:) { s/^-L//; push(@dirs, $_); next; }
293 # Otherwise we try to try to spot directories by a heuristic
294 # (this is a more complicated issue than it first appears)
295 if (m/:/ && -d $_) { push(@dirs, $_); next; }
296 # Only files should get this far...
297 my(@names, $name); # what filenames to look for
300 foreach $dir (@dirs, @dl_library_path) {
302 $dir =~ s/^([^:]+)$/:$1/;
304 foreach $name (@names) {
305 my($file) = "$dir:$name";
306 print STDERR " checking in $dir for $name\n" if $dl_debug;
309 next arg; # no need to look any further
316 # Otherwise we try to try to spot directories by a heuristic
317 # (this is a more complicated issue than it first appears)
318 if (m:/: && -d $_) { push(@dirs, $_); next; }
320 # VMS: we may be using native VMS directry syntax instead of
321 # Unix emulation, so check this as well
322 if ($Is_VMS && /[:>\]]/ && -d $_) { push(@dirs, $_); next; }
324 # Only files should get this far...
325 my(@names, $name); # what filenames to look for
326 if (m:-l: ) { # convert -lname to appropriate library name
328 push(@names,"lib$_.$dl_so");
329 push(@names,"lib$_.a");
330 } else { # Umm, a bare name. Try various alternatives:
331 # these should be ordered with the most likely first
332 push(@names,"$_.$dl_ext") unless m/\.$dl_ext$/o;
333 push(@names,"$_.$dl_so") unless m/\.$dl_so$/o;
334 push(@names,"lib$_.$dl_so") unless m:/:;
335 push(@names,"$_.a") if !m/\.a$/ and $dlsrc eq "dl_dld.xs";
338 foreach $dir (@dirs, @dl_library_path) {
340 chop($dir = VMS::Filespec::unixpath($dir)) if $Is_VMS;
341 foreach $name (@names) {
342 my($file) = "$dir/$name";
343 print STDERR " checking in $dir for $name\n" if $dl_debug;
344 $file = ($do_expand) ? dl_expandspec($file) : (-f $file && $file);
345 #$file = _check_file($file);
348 next arg; # no need to look any further
355 print STDERR " dl_findfile ignored non-existent directory: $_\n" unless -d $_;
357 print STDERR "dl_findfile found: @found\n";
359 return $found[0] unless wantarray;
366 # Optional function invoked if DynaLoader.pm sets $do_expand.
367 # Most systems do not require or use this function.
368 # Some systems may implement it in the dl_*.xs file in which case
369 # this autoload version will not be called but is harmless.
371 # This function is designed to deal with systems which treat some
372 # 'filenames' in a special way. For example VMS 'Logical Names'
373 # (something like unix environment variables - but different).
374 # This function should recognise such names and expand them into
376 # Must return undef if $spec is invalid or file does not exist.
378 my $file = $spec; # default output to input
380 if ($Is_VMS) { # dl_expandspec should be defined in dl_vms.xs
382 Carp::croak("dl_expandspec: should be defined in XS file!\n");
384 return undef unless -f $file;
386 print STDERR "dl_expandspec($spec) => $file\n" if $dl_debug;
390 sub dl_find_symbol_anywhere
394 foreach $libref (@dl_librefs) {
395 my $symref = dl_find_symbol($libref,$sym);
396 return $symref if $symref;
403 DynaLoader - Dynamically load C libraries into Perl code
405 dl_error(), dl_findfile(), dl_expandspec(), dl_load_file(), dl_find_symbol(), dl_find_symbol_anywhere(), dl_undef_symbols(), dl_install_xsub(), dl_load_flags(), bootstrap() - routines used by DynaLoader modules
411 @ISA = qw(... DynaLoader ...);
412 bootstrap YourPackage;
414 # optional method for 'global' loading
415 sub dl_load_flags { 0x01 }
420 This document defines a standard generic interface to the dynamic
421 linking mechanisms available on many platforms. Its primary purpose is
422 to implement automatic dynamic loading of Perl modules.
424 This document serves as both a specification for anyone wishing to
425 implement the DynaLoader for a new platform and as a guide for
426 anyone wishing to use the DynaLoader directly in an application.
428 The DynaLoader is designed to be a very simple high-level
429 interface that is sufficiently general to cover the requirements
430 of SunOS, HP-UX, NeXT, Linux, VMS and other platforms.
432 It is also hoped that the interface will cover the needs of OS/2, NT
433 etc and also allow pseudo-dynamic linking (using C<ld -A> at runtime).
435 It must be stressed that the DynaLoader, by itself, is practically
436 useless for accessing non-Perl libraries because it provides almost no
437 Perl-to-C 'glue'. There is, for example, no mechanism for calling a C
438 library function or supplying arguments. A C::DynaLib module
439 is available from CPAN sites which performs that function for some
442 DynaLoader Interface Summary
451 bootstrap($modulename) Perl
452 @filepaths = dl_findfile(@names) Perl
453 $flags = $modulename->dl_load_flags Perl
454 $symref = dl_find_symbol_anywhere($symbol) Perl
456 $libref = dl_load_file($filename, $flags) C
457 $symref = dl_find_symbol($libref, $symbol) C
458 @symbols = dl_undef_symbols() C
459 dl_install_xsub($name, $symref [, $filename]) C
460 $message = dl_error C
464 =item @dl_library_path
466 The standard/default list of directories in which dl_findfile() will
467 search for libraries etc. Directories are searched in order:
468 $dl_library_path[0], [1], ... etc
470 @dl_library_path is initialised to hold the list of 'normal' directories
471 (F</usr/lib>, etc) determined by B<Configure> (C<$Config{'libpth'}>). This should
472 ensure portability across a wide range of platforms.
474 @dl_library_path should also be initialised with any other directories
475 that can be determined from the environment at runtime (such as
476 LD_LIBRARY_PATH for SunOS).
478 After initialisation @dl_library_path can be manipulated by an
479 application using push and unshift before calling dl_findfile().
480 Unshift can be used to add directories to the front of the search order
481 either to save search time or to override libraries with the same name
482 in the 'normal' directories.
484 The load function that dl_load_file() calls may require an absolute
485 pathname. The dl_findfile() function and @dl_library_path can be
486 used to search for and return the absolute pathname for the
487 library/object that you wish to load.
489 =item @dl_resolve_using
491 A list of additional libraries or other shared objects which can be
492 used to resolve any undefined symbols that might be generated by a
493 later call to load_file().
495 This is only required on some platforms which do not handle dependent
496 libraries automatically. For example the Socket Perl extension
497 library (F<auto/Socket/Socket.so>) contains references to many socket
498 functions which need to be resolved when it's loaded. Most platforms
499 will automatically know where to find the 'dependent' library (e.g.,
500 F</usr/lib/libsocket.so>). A few platforms need to be told the
501 location of the dependent library explicitly. Use @dl_resolve_using
506 @dl_resolve_using = dl_findfile('-lsocket');
508 =item @dl_require_symbols
510 A list of one or more symbol names that are in the library/object file
511 to be dynamically loaded. This is only required on some platforms.
515 An array of the handles returned by successful calls to dl_load_file(),
516 made by bootstrap, in the order in which they were loaded.
517 Can be used with dl_find_symbol() to look for a symbol in any of
522 An array of module (package) names that have been bootstrap'ed.
528 $message = dl_error();
530 Error message text from the last failed DynaLoader function. Note
531 that, similar to errno in unix, a successful function call does not
534 Implementations should detect the error as soon as it occurs in any of
535 the other functions and save the corresponding message for later
536 retrieval. This will avoid problems on some platforms (such as SunOS)
537 where the error message is very temporary (e.g., dlerror()).
541 Internal debugging messages are enabled when $dl_debug is set true.
542 Currently setting $dl_debug only affects the Perl side of the
543 DynaLoader. These messages should help an application developer to
544 resolve any DynaLoader usage problems.
546 $dl_debug is set to C<$ENV{'PERL_DL_DEBUG'}> if defined.
548 For the DynaLoader developer/porter there is a similar debugging
549 variable added to the C code (see dlutils.c) and enabled if Perl was
550 built with the B<-DDEBUGGING> flag. This can also be set via the
551 PERL_DL_DEBUG environment variable. Set to 1 for minimal information or
558 @filepaths = dl_findfile(@names)
560 Determine the full paths (including file suffix) of one or more
561 loadable files given their generic names and optionally one or more
562 directories. Searches directories in @dl_library_path by default and
563 returns an empty list if no files were found.
565 Names can be specified in a variety of platform independent forms. Any
566 names in the form B<-lname> are converted into F<libname.*>, where F<.*> is
567 an appropriate suffix for the platform.
569 If a name does not already have a suitable prefix and/or suffix then
570 the corresponding file will be searched for by trying combinations of
571 prefix and suffix appropriate to the platform: "$name.o", "lib$name.*"
574 If any directories are included in @names they are searched before
575 @dl_library_path. Directories may be specified as B<-Ldir>. Any other
576 names are treated as filenames to be searched for.
578 Using arguments of the form C<-Ldir> and C<-lname> is recommended.
582 @dl_resolve_using = dl_findfile(qw(-L/usr/5lib -lposix));
585 =item dl_expandspec()
589 $filepath = dl_expandspec($spec)
591 Some unusual systems, such as VMS, require special filename handling in
592 order to deal with symbolic names for files (i.e., VMS's Logical Names).
594 To support these systems a dl_expandspec() function can be implemented
595 either in the F<dl_*.xs> file or code can be added to the autoloadable
596 dl_expandspec() function in F<DynaLoader.pm>. See F<DynaLoader.pm> for
603 $libref = dl_load_file($filename, $flags)
605 Dynamically load $filename, which must be the path to a shared object
606 or library. An opaque 'library reference' is returned as a handle for
607 the loaded object. Returns undef on error.
609 The $flags argument to alters dl_load_file behaviour.
612 0x01 make symbols available for linking later dl_load_file's.
613 (only known to work on Solaris 2 using dlopen(RTLD_GLOBAL))
614 (ignored under VMS; this is a normal part of image linking)
616 (On systems that provide a handle for the loaded object such as SunOS
617 and HPUX, $libref will be that handle. On other systems $libref will
618 typically be $filename or a pointer to a buffer containing $filename.
619 The application should not examine or alter $libref in any way.)
621 This is the function that does the real work. It should use the
622 current values of @dl_require_symbols and @dl_resolve_using if required.
624 SunOS: dlopen($filename)
625 HP-UX: shl_load($filename)
626 Linux: dld_create_reference(@dl_require_symbols); dld_link($filename)
627 NeXT: rld_load($filename, @dl_resolve_using)
628 VMS: lib$find_image_symbol($filename,$dl_require_symbols[0])
630 (The dlopen() function is also used by Solaris and some versions of
631 Linux, and is a common choice when providing a "wrapper" on other
632 mechanisms as is done in the OS/2 port.)
638 $flags = dl_loadflags $modulename;
640 Designed to be a method call, and to be overridden by a derived class
641 (i.e. a class which has DynaLoader in its @ISA). The definition in
642 DynaLoader itself returns 0, which produces standard behavior from
645 =item dl_find_symbol()
649 $symref = dl_find_symbol($libref, $symbol)
651 Return the address of the symbol $symbol or C<undef> if not found. If the
652 target system has separate functions to search for symbols of different
653 types then dl_find_symbol() should search for function symbols first and
656 The exact manner in which the address is returned in $symref is not
657 currently defined. The only initial requirement is that $symref can
658 be passed to, and understood by, dl_install_xsub().
660 SunOS: dlsym($libref, $symbol)
661 HP-UX: shl_findsym($libref, $symbol)
662 Linux: dld_get_func($symbol) and/or dld_get_symbol($symbol)
663 NeXT: rld_lookup("_$symbol")
664 VMS: lib$find_image_symbol($libref,$symbol)
667 =item dl_find_symbol_anywhere()
671 $symref = dl_find_symbol_anywhere($symbol)
673 Applies dl_find_symbol() to the members of @dl_librefs and returns
674 the first match found.
676 =item dl_undef_symbols()
680 @symbols = dl_undef_symbols()
682 Return a list of symbol names which remain undefined after load_file().
683 Returns C<()> if not known. Don't worry if your platform does not provide
684 a mechanism for this. Most do not need it and hence do not provide it,
685 they just return an empty list.
688 =item dl_install_xsub()
692 dl_install_xsub($perl_name, $symref [, $filename])
694 Create a new Perl external subroutine named $perl_name using $symref as
695 a pointer to the function which implements the routine. This is simply
696 a direct call to newXSUB(). Returns a reference to the installed
699 The $filename parameter is used by Perl to identify the source file for
700 the function if required by die(), caller() or the debugger. If
701 $filename is not defined then "DynaLoader" will be used.
710 This is the normal entry point for automatic dynamic loading in Perl.
712 It performs the following actions:
718 locates an auto/$module directory by searching @INC
722 uses dl_findfile() to determine the filename to load
726 sets @dl_require_symbols to C<("boot_$module")>
730 executes an F<auto/$module/$module.bs> file if it exists
731 (typically used to add to @dl_resolve_using any files which
732 are required to load the module on the current platform)
736 calls dl_load_flags() to determine how to load the file.
740 calls dl_load_file() to load the file
744 calls dl_undef_symbols() and warns if any symbols are undefined
748 calls dl_find_symbol() for "boot_$module"
752 calls dl_install_xsub() to install it as "${module}::bootstrap"
756 calls &{"${module}::bootstrap"} to bootstrap the module (actually
757 it uses the function reference returned by dl_install_xsub for speed)
766 Tim Bunce, 11 August 1994.
768 This interface is based on the work and comments of (in no particular
769 order): Larry Wall, Robert Sanders, Dean Roehrich, Jeff Okamoto, Anno
770 Siegel, Thomas Neumann, Paul Marquess, Charles Bailey, myself and others.
772 Larry Wall designed the elegant inherited bootstrap mechanism and
773 implemented the first Perl 5 dynamic loader using it.
775 Solaris global loading added by Nick Ing-Simmons with design/coding
776 assistance from Tim Bunce, January 1996.