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
97 # from environment variables.
98 push(@dl_library_path, split(/:/, $ENV{$Config::Config{ldlibpthname}}))
99 if exists $Config::Config{ldlibpthname} &&
100 $Config::Config{ldlibpthname} ne '' &&
101 exists $ENV{$Config::Config{ldlibpthname}} ;;
102 # E.g. HP-UX supports both its native SHLIB_PATH *and* LD_LIBRARY_PATH.
103 push(@dl_library_path, split(/:/, $ENV{LD_LIBRARY_PATH}))
104 if exists $ENV{LD_LIBRARY_PATH};
106 # No prizes for guessing why we don't say 'bootstrap DynaLoader;' here.
107 boot_DynaLoader('DynaLoader') if defined(&boot_DynaLoader) &&
108 !defined(&dl_load_file);
112 print STDERR "DynaLoader.pm loaded (@INC, @dl_library_path)\n";
113 print STDERR "DynaLoader not linked into this perl\n"
114 unless defined(&boot_DynaLoader);
117 1; # End of main code
120 sub croak { require Carp; Carp::croak(@_) }
122 # The bootstrap function cannot be autoloaded (without complications)
123 # so we define it here:
126 # use local vars to enable $module.bs script to edit values
128 local($module) = $args[0];
133 Carp::confess("Usage: DynaLoader::bootstrap(module)");
136 # A common error on platforms which don't support dynamic loading.
137 # Since it's fatal and potentially confusing we give a detailed message.
138 croak("Can't load module $module, dynamic loading not available in this perl.\n".
139 " (You may need to build a new perl executable which either supports\n".
140 " dynamic loading or has the $module module statically linked into it.)\n")
141 unless defined(&dl_load_file);
143 my @modparts = split(/::/,$module);
144 my $modfname = $modparts[-1];
146 # Some systems have restrictions on files names for DLL's etc.
147 # mod2fname returns appropriate file base name (typically truncated)
148 # It may also edit @modparts if required.
149 $modfname = &mod2fname(\@modparts) if defined &mod2fname;
151 my $modpname = join('/',@modparts);
153 print STDERR "DynaLoader::bootstrap for $module ",
154 "(auto/$modpname/$modfname.$dl_dlext)\n" if $dl_debug;
157 chop($_ = VMS::Filespec::unixpath($_)) if $Is_VMS;
158 my $dir = "$_/auto/$modpname";
159 next unless -d $dir; # skip over uninteresting directories
161 # check for common cases to avoid autoload of dl_findfile
162 my $try = "$dir/$modfname.$dl_dlext";
163 last if $file = ($do_expand) ? dl_expandspec($try) : (-f $try && $try);
165 # no luck here, save dir for possible later dl_findfile search
168 # last resort, let dl_findfile have a go in all known locations
169 $file = dl_findfile(map("-L$_",@dirs,@INC), $modfname) unless $file;
171 croak("Can't locate loadable object for module $module in \@INC (\@INC contains: @INC)")
172 unless $file; # wording similar to error from 'require'
174 my $bootname = "boot_$module";
175 $bootname =~ s/\W/_/g;
176 @dl_require_symbols = ($bootname);
178 # Execute optional '.bootstrap' perl script for this module.
179 # The .bs file can be used to configure @dl_resolve_using etc to
180 # match the needs of the individual module on this architecture.
182 $bs =~ s/(\.\w+)?$/\.bs/; # look for .bs 'beside' the library
183 if (-s $bs) { # only read file if it's not empty
184 print STDERR "BS: $bs ($^O, $dlsrc)\n" if $dl_debug;
186 warn "$bs: $@\n" if $@;
189 # Many dynamic extension loading problems will appear to come from
190 # this section of code: XYZ failed at line 123 of DynaLoader.pm.
191 # Often these errors are actually occurring in the initialisation
192 # C code of the extension XS file. Perl reports the error as being
193 # in this perl code simply because this was the last perl code
196 my $libref = dl_load_file($file, $module->dl_load_flags) or
197 croak("Can't load '$file' for module $module: ".dl_error());
199 push(@dl_librefs,$libref); # record loaded object
201 my @unresolved = dl_undef_symbols();
204 Carp::carp("Undefined symbols present after loading $file: @unresolved\n");
207 my $boot_symbol_ref = dl_find_symbol($libref, $bootname) or
208 croak("Can't find '$bootname' symbol in $file\n");
210 my $xs = dl_install_xsub("${module}::bootstrap", $boot_symbol_ref, $file);
212 push(@dl_modules, $module); # record loaded module
214 # See comment block above
219 #sub _check_file { # private utility to handle dl_expandspec vs -f tests
221 # return $file if (!$do_expand && -f $file); # the common case
222 # return $file if ( $do_expand && ($file=dl_expandspec($file)));
227 # Let autosplit and the autoloader deal with these functions:
232 # Read ext/DynaLoader/DynaLoader.doc for detailed information.
233 # This function does not automatically consider the architecture
234 # or the perl library auto directories.
236 my (@dirs, $dir); # which directories to search
237 my (@found); # full paths to real files we have found
240 print OUT ' my $dl_ext= ' . to_string($Config::Config{'dlext'}) .
241 "; # \$Config::Config{'dlext'} suffix for perl extensions\n";
242 print OUT ' my $dl_so = ' . to_string($Config::Config{'so'}) .
243 "; # \$Config::Config{'so'} suffix for shared libraries\n";
247 print STDERR "dl_findfile(@args)\n" if $dl_debug;
249 # accumulate directories but process files as they appear
250 arg: foreach(@args) {
251 # Special fast case: full filepath requires no search
252 if ($Is_VMS && m%[:>/\]]% && -f $_) {
253 push(@found,dl_expandspec(VMS::Filespec::vmsify($_)));
254 last arg unless wantarray;
257 elsif (m:/: && -f $_ && !$do_expand) {
259 last arg unless wantarray;
263 # Deal with directories first:
264 # Using a -L prefix is the preferred option (faster and more robust)
265 if (m:^-L:) { s/^-L//; push(@dirs, $_); next; }
267 # Otherwise we try to try to spot directories by a heuristic
268 # (this is a more complicated issue than it first appears)
269 if (m:/: && -d $_) { push(@dirs, $_); next; }
271 # VMS: we may be using native VMS directry syntax instead of
272 # Unix emulation, so check this as well
273 if ($Is_VMS && /[:>\]]/ && -d $_) { push(@dirs, $_); next; }
275 # Only files should get this far...
276 my(@names, $name); # what filenames to look for
277 if (m:-l: ) { # convert -lname to appropriate library name
279 push(@names,"lib$_.$dl_so");
280 push(@names,"lib$_.a");
281 } else { # Umm, a bare name. Try various alternatives:
282 # these should be ordered with the most likely first
283 push(@names,"$_.$dl_ext") unless m/\.$dl_ext$/o;
284 push(@names,"$_.$dl_so") unless m/\.$dl_so$/o;
285 push(@names,"lib$_.$dl_so") unless m:/:;
286 push(@names,"$_.a") if !m/\.a$/ and $dlsrc eq "dl_dld.xs";
289 foreach $dir (@dirs, @dl_library_path) {
291 chop($dir = VMS::Filespec::unixpath($dir)) if $Is_VMS;
292 foreach $name (@names) {
293 my($file) = "$dir/$name";
294 print STDERR " checking in $dir for $name\n" if $dl_debug;
295 $file = ($do_expand) ? dl_expandspec($file) : (-f $file && $file);
296 #$file = _check_file($file);
299 next arg; # no need to look any further
306 print STDERR " dl_findfile ignored non-existent directory: $_\n" unless -d $_;
308 print STDERR "dl_findfile found: @found\n";
310 return $found[0] unless wantarray;
317 # Optional function invoked if DynaLoader.pm sets $do_expand.
318 # Most systems do not require or use this function.
319 # Some systems may implement it in the dl_*.xs file in which case
320 # this autoload version will not be called but is harmless.
322 # This function is designed to deal with systems which treat some
323 # 'filenames' in a special way. For example VMS 'Logical Names'
324 # (something like unix environment variables - but different).
325 # This function should recognise such names and expand them into
327 # Must return undef if $spec is invalid or file does not exist.
329 my $file = $spec; # default output to input
331 if ($Is_VMS) { # dl_expandspec should be defined in dl_vms.xs
333 Carp::croak("dl_expandspec: should be defined in XS file!\n");
335 return undef unless -f $file;
337 print STDERR "dl_expandspec($spec) => $file\n" if $dl_debug;
341 sub dl_find_symbol_anywhere
345 foreach $libref (@dl_librefs) {
346 my $symref = dl_find_symbol($libref,$sym);
347 return $symref if $symref;
354 DynaLoader - Dynamically load C libraries into Perl code
356 dl_error(), dl_findfile(), dl_expandspec(), dl_load_file(), dl_find_symbol(), dl_find_symbol_anywhere(), dl_undef_symbols(), dl_install_xsub(), dl_load_flags(), bootstrap() - routines used by DynaLoader modules
362 @ISA = qw(... DynaLoader ...);
363 bootstrap YourPackage;
365 # optional method for 'global' loading
366 sub dl_load_flags { 0x01 }
371 This document defines a standard generic interface to the dynamic
372 linking mechanisms available on many platforms. Its primary purpose is
373 to implement automatic dynamic loading of Perl modules.
375 This document serves as both a specification for anyone wishing to
376 implement the DynaLoader for a new platform and as a guide for
377 anyone wishing to use the DynaLoader directly in an application.
379 The DynaLoader is designed to be a very simple high-level
380 interface that is sufficiently general to cover the requirements
381 of SunOS, HP-UX, NeXT, Linux, VMS and other platforms.
383 It is also hoped that the interface will cover the needs of OS/2, NT
384 etc and also allow pseudo-dynamic linking (using C<ld -A> at runtime).
386 It must be stressed that the DynaLoader, by itself, is practically
387 useless for accessing non-Perl libraries because it provides almost no
388 Perl-to-C 'glue'. There is, for example, no mechanism for calling a C
389 library function or supplying arguments. A C::DynaLib module
390 is available from CPAN sites which performs that function for some
393 DynaLoader Interface Summary
402 bootstrap($modulename) Perl
403 @filepaths = dl_findfile(@names) Perl
404 $flags = $modulename->dl_load_flags Perl
405 $symref = dl_find_symbol_anywhere($symbol) Perl
407 $libref = dl_load_file($filename, $flags) C
408 $symref = dl_find_symbol($libref, $symbol) C
409 @symbols = dl_undef_symbols() C
410 dl_install_xsub($name, $symref [, $filename]) C
411 $message = dl_error C
415 =item @dl_library_path
417 The standard/default list of directories in which dl_findfile() will
418 search for libraries etc. Directories are searched in order:
419 $dl_library_path[0], [1], ... etc
421 @dl_library_path is initialised to hold the list of 'normal' directories
422 (F</usr/lib>, etc) determined by B<Configure> (C<$Config{'libpth'}>). This should
423 ensure portability across a wide range of platforms.
425 @dl_library_path should also be initialised with any other directories
426 that can be determined from the environment at runtime (such as
427 LD_LIBRARY_PATH for SunOS).
429 After initialisation @dl_library_path can be manipulated by an
430 application using push and unshift before calling dl_findfile().
431 Unshift can be used to add directories to the front of the search order
432 either to save search time or to override libraries with the same name
433 in the 'normal' directories.
435 The load function that dl_load_file() calls may require an absolute
436 pathname. The dl_findfile() function and @dl_library_path can be
437 used to search for and return the absolute pathname for the
438 library/object that you wish to load.
440 =item @dl_resolve_using
442 A list of additional libraries or other shared objects which can be
443 used to resolve any undefined symbols that might be generated by a
444 later call to load_file().
446 This is only required on some platforms which do not handle dependent
447 libraries automatically. For example the Socket Perl extension
448 library (F<auto/Socket/Socket.so>) contains references to many socket
449 functions which need to be resolved when it's loaded. Most platforms
450 will automatically know where to find the 'dependent' library (e.g.,
451 F</usr/lib/libsocket.so>). A few platforms need to be told the
452 location of the dependent library explicitly. Use @dl_resolve_using
457 @dl_resolve_using = dl_findfile('-lsocket');
459 =item @dl_require_symbols
461 A list of one or more symbol names that are in the library/object file
462 to be dynamically loaded. This is only required on some platforms.
466 An array of the handles returned by successful calls to dl_load_file(),
467 made by bootstrap, in the order in which they were loaded.
468 Can be used with dl_find_symbol() to look for a symbol in any of
473 An array of module (package) names that have been bootstrap'ed.
479 $message = dl_error();
481 Error message text from the last failed DynaLoader function. Note
482 that, similar to errno in unix, a successful function call does not
485 Implementations should detect the error as soon as it occurs in any of
486 the other functions and save the corresponding message for later
487 retrieval. This will avoid problems on some platforms (such as SunOS)
488 where the error message is very temporary (e.g., dlerror()).
492 Internal debugging messages are enabled when $dl_debug is set true.
493 Currently setting $dl_debug only affects the Perl side of the
494 DynaLoader. These messages should help an application developer to
495 resolve any DynaLoader usage problems.
497 $dl_debug is set to C<$ENV{'PERL_DL_DEBUG'}> if defined.
499 For the DynaLoader developer/porter there is a similar debugging
500 variable added to the C code (see dlutils.c) and enabled if Perl was
501 built with the B<-DDEBUGGING> flag. This can also be set via the
502 PERL_DL_DEBUG environment variable. Set to 1 for minimal information or
509 @filepaths = dl_findfile(@names)
511 Determine the full paths (including file suffix) of one or more
512 loadable files given their generic names and optionally one or more
513 directories. Searches directories in @dl_library_path by default and
514 returns an empty list if no files were found.
516 Names can be specified in a variety of platform independent forms. Any
517 names in the form B<-lname> are converted into F<libname.*>, where F<.*> is
518 an appropriate suffix for the platform.
520 If a name does not already have a suitable prefix and/or suffix then
521 the corresponding file will be searched for by trying combinations of
522 prefix and suffix appropriate to the platform: "$name.o", "lib$name.*"
525 If any directories are included in @names they are searched before
526 @dl_library_path. Directories may be specified as B<-Ldir>. Any other
527 names are treated as filenames to be searched for.
529 Using arguments of the form C<-Ldir> and C<-lname> is recommended.
533 @dl_resolve_using = dl_findfile(qw(-L/usr/5lib -lposix));
536 =item dl_expandspec()
540 $filepath = dl_expandspec($spec)
542 Some unusual systems, such as VMS, require special filename handling in
543 order to deal with symbolic names for files (i.e., VMS's Logical Names).
545 To support these systems a dl_expandspec() function can be implemented
546 either in the F<dl_*.xs> file or code can be added to the autoloadable
547 dl_expandspec() function in F<DynaLoader.pm>. See F<DynaLoader.pm> for
554 $libref = dl_load_file($filename, $flags)
556 Dynamically load $filename, which must be the path to a shared object
557 or library. An opaque 'library reference' is returned as a handle for
558 the loaded object. Returns undef on error.
560 The $flags argument to alters dl_load_file behaviour.
563 0x01 make symbols available for linking later dl_load_file's.
564 (only known to work on Solaris 2 using dlopen(RTLD_GLOBAL))
565 (ignored under VMS; this is a normal part of image linking)
567 (On systems that provide a handle for the loaded object such as SunOS
568 and HPUX, $libref will be that handle. On other systems $libref will
569 typically be $filename or a pointer to a buffer containing $filename.
570 The application should not examine or alter $libref in any way.)
572 This is the function that does the real work. It should use the
573 current values of @dl_require_symbols and @dl_resolve_using if required.
575 SunOS: dlopen($filename)
576 HP-UX: shl_load($filename)
577 Linux: dld_create_reference(@dl_require_symbols); dld_link($filename)
578 NeXT: rld_load($filename, @dl_resolve_using)
579 VMS: lib$find_image_symbol($filename,$dl_require_symbols[0])
581 (The dlopen() function is also used by Solaris and some versions of
582 Linux, and is a common choice when providing a "wrapper" on other
583 mechanisms as is done in the OS/2 port.)
589 $flags = dl_loadflags $modulename;
591 Designed to be a method call, and to be overridden by a derived class
592 (i.e. a class which has DynaLoader in its @ISA). The definition in
593 DynaLoader itself returns 0, which produces standard behavior from
596 =item dl_find_symbol()
600 $symref = dl_find_symbol($libref, $symbol)
602 Return the address of the symbol $symbol or C<undef> if not found. If the
603 target system has separate functions to search for symbols of different
604 types then dl_find_symbol() should search for function symbols first and
607 The exact manner in which the address is returned in $symref is not
608 currently defined. The only initial requirement is that $symref can
609 be passed to, and understood by, dl_install_xsub().
611 SunOS: dlsym($libref, $symbol)
612 HP-UX: shl_findsym($libref, $symbol)
613 Linux: dld_get_func($symbol) and/or dld_get_symbol($symbol)
614 NeXT: rld_lookup("_$symbol")
615 VMS: lib$find_image_symbol($libref,$symbol)
618 =item dl_find_symbol_anywhere()
622 $symref = dl_find_symbol_anywhere($symbol)
624 Applies dl_find_symbol() to the members of @dl_librefs and returns
625 the first match found.
627 =item dl_undef_symbols()
631 @symbols = dl_undef_symbols()
633 Return a list of symbol names which remain undefined after load_file().
634 Returns C<()> if not known. Don't worry if your platform does not provide
635 a mechanism for this. Most do not need it and hence do not provide it,
636 they just return an empty list.
639 =item dl_install_xsub()
643 dl_install_xsub($perl_name, $symref [, $filename])
645 Create a new Perl external subroutine named $perl_name using $symref as
646 a pointer to the function which implements the routine. This is simply
647 a direct call to newXSUB(). Returns a reference to the installed
650 The $filename parameter is used by Perl to identify the source file for
651 the function if required by die(), caller() or the debugger. If
652 $filename is not defined then "DynaLoader" will be used.
661 This is the normal entry point for automatic dynamic loading in Perl.
663 It performs the following actions:
669 locates an auto/$module directory by searching @INC
673 uses dl_findfile() to determine the filename to load
677 sets @dl_require_symbols to C<("boot_$module")>
681 executes an F<auto/$module/$module.bs> file if it exists
682 (typically used to add to @dl_resolve_using any files which
683 are required to load the module on the current platform)
687 calls dl_load_flags() to determine how to load the file.
691 calls dl_load_file() to load the file
695 calls dl_undef_symbols() and warns if any symbols are undefined
699 calls dl_find_symbol() for "boot_$module"
703 calls dl_install_xsub() to install it as "${module}::bootstrap"
707 calls &{"${module}::bootstrap"} to bootstrap the module (actually
708 it uses the function reference returned by dl_install_xsub for speed)
717 Tim Bunce, 11 August 1994.
719 This interface is based on the work and comments of (in no particular
720 order): Larry Wall, Robert Sanders, Dean Roehrich, Jeff Okamoto, Anno
721 Siegel, Thomas Neumann, Paul Marquess, Charles Bailey, myself and others.
723 Larry Wall designed the elegant inherited bootstrap mechanism and
724 implemented the first Perl 5 dynamic loader using it.
726 Solaris global loading added by Nick Ing-Simmons with design/coding
727 assistance from Tim Bunce, January 1996.