6 $value =~ s/\\/\\\\'/g;
11 unlink "DynaLoader.pm" if -f "DynaLoader.pm";
12 open OUT, ">DynaLoader.pm" or die $!;
15 # Generated from DynaLoader.pm.PL (resolved %Config::Config values)
19 # And Gandalf said: 'Many folk like to know beforehand what is to
20 # be set on the table; but those who have laboured to prepare the
21 # feast like to keep their secret; for wonder makes the words of
24 # (Quote from Tolkien sugested by Anno Siegel.)
26 # See pod text at end of file for documentation.
27 # See also ext/DynaLoader/README in source tree for other information.
29 # Tim.Bunce@ig.co.uk, August 1994
31 $VERSION = $VERSION = "1.03"; # avoid typo warning
34 *AUTOLOAD = \&AutoLoader::AUTOLOAD;
36 # The following require can't be removed during maintenance
37 # releases, sadly, because of the risk of buggy code that does
38 # require Carp; Carp::croak "..."; without brackets dying
39 # if Carp hasn't been loaded in earlier compile time. :-(
40 # We'll let those bugs get found on the development track.
41 require Carp if $] < 5.00450;
44 # enable debug/trace messages from DynaLoader perl code
45 $dl_debug = $ENV{PERL_DL_DEBUG} || 0 unless defined $dl_debug;
48 # Flags to alter dl_load_file behaviour. Assigned bits:
49 # 0x01 make symbols available for linking later dl_load_file's.
50 # (only known to work on Solaris 2 using dlopen(RTLD_GLOBAL))
51 # (ignored under VMS; effect is built-in to image linking)
53 # This is called as a class method $module->dl_load_flags. The
54 # definition here will be inherited and result on "default" loading
55 # behaviour unless a sub-class of DynaLoader defines its own version.
58 sub dl_load_flags { 0x00 }
61 # = @Config::Config{'dlext', 'dlsrc'};
64 print OUT " (\$dl_dlext, \$dlsrc) = (",
65 to_string($Config::Config{'dlext'}), ",",
66 to_string($Config::Config{'dlsrc'}), ")\n;" ;
70 # Some systems need special handling to expand file specifications
71 # (VMS support by Charles Bailey <bailey@HMIVAX.HUMGEN.UPENN.EDU>)
72 # See dl_expandspec() for more details. Should be harmless but
73 # inefficient to define on systems that don't need it.
74 $do_expand = $Is_VMS = $^O eq 'VMS';
76 @dl_require_symbols = (); # names of symbols we need
77 @dl_resolve_using = (); # names of files to link with
78 @dl_library_path = (); # path to look for files
79 @dl_librefs = (); # things we have loaded
80 @dl_modules = (); # Modules we have loaded
82 # This is a fix to support DLD's unfortunate desire to relink -lc
83 @dl_resolve_using = dl_findfile('-lc') if $dlsrc eq "dl_dld.xs";
85 # Initialise @dl_library_path with the 'standard' library path
86 # for this platform as determined by Configure
88 # push(@dl_library_path, split(' ', $Config::Config{'libpth'});
91 print OUT "push(\@dl_library_path, split(' ', ",
92 to_string($Config::Config{'libpth'}), "));\n";
96 # Add to @dl_library_path any extra directories we can gather from
97 # environment variables. So far LD_LIBRARY_PATH is the only known
98 # variable used for this purpose. Others may be added later.
99 push(@dl_library_path, split(/:/, $ENV{LD_LIBRARY_PATH}))
100 if $ENV{LD_LIBRARY_PATH};
103 # No prizes for guessing why we don't say 'bootstrap DynaLoader;' here.
104 boot_DynaLoader('DynaLoader') if defined(&boot_DynaLoader);
108 print STDERR "DynaLoader.pm loaded (@INC, @dl_library_path)\n";
109 print STDERR "DynaLoader not linked into this perl\n"
110 unless defined(&boot_DynaLoader);
113 1; # End of main code
116 sub croak { require Carp; Carp::croak(@_) }
118 # The bootstrap function cannot be autoloaded (without complications)
119 # so we define it here:
122 # use local vars to enable $module.bs script to edit values
124 local($module) = $args[0];
129 Carp::confess("Usage: DynaLoader::bootstrap(module)");
132 # A common error on platforms which don't support dynamic loading.
133 # Since it's fatal and potentially confusing we give a detailed message.
134 croak("Can't load module $module, dynamic loading not available in this perl.\n".
135 " (You may need to build a new perl executable which either supports\n".
136 " dynamic loading or has the $module module statically linked into it.)\n")
137 unless defined(&dl_load_file);
139 my @modparts = split(/::/,$module);
140 my $modfname = $modparts[-1];
142 # Some systems have restrictions on files names for DLL's etc.
143 # mod2fname returns appropriate file base name (typically truncated)
144 # It may also edit @modparts if required.
145 $modfname = &mod2fname(\@modparts) if defined &mod2fname;
147 my $modpname = join('/',@modparts);
149 print STDERR "DynaLoader::bootstrap for $module ",
150 "(auto/$modpname/$modfname.$dl_dlext)\n" if $dl_debug;
153 chop($_ = VMS::Filespec::unixpath($_)) if $Is_VMS;
154 my $dir = "$_/auto/$modpname";
155 next unless -d $dir; # skip over uninteresting directories
157 # check for common cases to avoid autoload of dl_findfile
158 my $try = "$dir/$modfname.$dl_dlext";
159 last if $file = ($do_expand) ? dl_expandspec($try) : (-f $try && $try);
161 # no luck here, save dir for possible later dl_findfile search
164 # last resort, let dl_findfile have a go in all known locations
165 $file = dl_findfile(map("-L$_",@dirs,@INC), $modfname) unless $file;
167 croak("Can't locate loadable object for module $module in \@INC (\@INC contains: @INC)")
168 unless $file; # wording similar to error from 'require'
170 my $bootname = "boot_$module";
171 $bootname =~ s/\W/_/g;
172 @dl_require_symbols = ($bootname);
174 # Execute optional '.bootstrap' perl script for this module.
175 # The .bs file can be used to configure @dl_resolve_using etc to
176 # match the needs of the individual module on this architecture.
178 $bs =~ s/(\.\w+)?$/\.bs/; # look for .bs 'beside' the library
179 if (-s $bs) { # only read file if it's not empty
180 print STDERR "BS: $bs ($^O, $dlsrc)\n" if $dl_debug;
182 warn "$bs: $@\n" if $@;
185 # Many dynamic extension loading problems will appear to come from
186 # this section of code: XYZ failed at line 123 of DynaLoader.pm.
187 # Often these errors are actually occurring in the initialisation
188 # C code of the extension XS file. Perl reports the error as being
189 # in this perl code simply because this was the last perl code
192 my $libref = dl_load_file($file, $module->dl_load_flags) or
193 croak("Can't load '$file' for module $module: ".dl_error()."\n");
195 push(@dl_librefs,$libref); # record loaded object
197 my @unresolved = dl_undef_symbols();
200 Carp::carp("Undefined symbols present after loading $file: @unresolved\n");
203 my $boot_symbol_ref = dl_find_symbol($libref, $bootname) or
204 croak("Can't find '$bootname' symbol in $file\n");
206 my $xs = dl_install_xsub("${module}::bootstrap", $boot_symbol_ref, $file);
208 push(@dl_modules, $module); # record loaded module
210 # See comment block above
215 #sub _check_file { # private utility to handle dl_expandspec vs -f tests
217 # return $file if (!$do_expand && -f $file); # the common case
218 # return $file if ( $do_expand && ($file=dl_expandspec($file)));
223 # Let autosplit and the autoloader deal with these functions:
228 # Read ext/DynaLoader/DynaLoader.doc for detailed information.
229 # This function does not automatically consider the architecture
230 # or the perl library auto directories.
232 my (@dirs, $dir); # which directories to search
233 my (@found); # full paths to real files we have found
236 print OUT ' my $dl_ext= ' . to_string($Config::Config{'dlext'}) .
237 "; # \$Config::Config{'dlext'} suffix for perl extensions\n";
238 print OUT ' my $dl_so = ' . to_string($Config::Config{'so'}) .
239 "; # \$Config::Config{'so'} suffix for shared libraries\n";
243 print STDERR "dl_findfile(@args)\n" if $dl_debug;
245 # accumulate directories but process files as they appear
246 arg: foreach(@args) {
247 # Special fast case: full filepath requires no search
248 if ($Is_VMS && m%[:>/\]]% && -f $_) {
249 push(@found,dl_expandspec(VMS::Filespec::vmsify($_)));
250 last arg unless wantarray;
253 elsif (m:/: && -f $_ && !$do_expand) {
255 last arg unless wantarray;
259 # Deal with directories first:
260 # Using a -L prefix is the preferred option (faster and more robust)
261 if (m:^-L:) { s/^-L//; push(@dirs, $_); next; }
263 # Otherwise we try to try to spot directories by a heuristic
264 # (this is a more complicated issue than it first appears)
265 if (m:/: && -d $_) { push(@dirs, $_); next; }
267 # VMS: we may be using native VMS directry syntax instead of
268 # Unix emulation, so check this as well
269 if ($Is_VMS && /[:>\]]/ && -d $_) { push(@dirs, $_); next; }
271 # Only files should get this far...
272 my(@names, $name); # what filenames to look for
273 if (m:-l: ) { # convert -lname to appropriate library name
275 push(@names,"lib$_.$dl_so");
276 push(@names,"lib$_.a");
277 } else { # Umm, a bare name. Try various alternatives:
278 # these should be ordered with the most likely first
279 push(@names,"$_.$dl_ext") unless m/\.$dl_ext$/o;
280 push(@names,"$_.$dl_so") unless m/\.$dl_so$/o;
281 push(@names,"lib$_.$dl_so") unless m:/:;
282 push(@names,"$_.a") if !m/\.a$/ and $dlsrc eq "dl_dld.xs";
285 foreach $dir (@dirs, @dl_library_path) {
287 chop($dir = VMS::Filespec::unixpath($dir)) if $Is_VMS;
288 foreach $name (@names) {
289 my($file) = "$dir/$name";
290 print STDERR " checking in $dir for $name\n" if $dl_debug;
291 $file = ($do_expand) ? dl_expandspec($file) : (-f $file && $file);
292 #$file = _check_file($file);
295 next arg; # no need to look any further
302 print STDERR " dl_findfile ignored non-existent directory: $_\n" unless -d $_;
304 print STDERR "dl_findfile found: @found\n";
306 return $found[0] unless wantarray;
313 # Optional function invoked if DynaLoader.pm sets $do_expand.
314 # Most systems do not require or use this function.
315 # Some systems may implement it in the dl_*.xs file in which case
316 # this autoload version will not be called but is harmless.
318 # This function is designed to deal with systems which treat some
319 # 'filenames' in a special way. For example VMS 'Logical Names'
320 # (something like unix environment variables - but different).
321 # This function should recognise such names and expand them into
323 # Must return undef if $spec is invalid or file does not exist.
325 my $file = $spec; # default output to input
327 if ($Is_VMS) { # dl_expandspec should be defined in dl_vms.xs
329 Carp::croak("dl_expandspec: should be defined in XS file!\n");
331 return undef unless -f $file;
333 print STDERR "dl_expandspec($spec) => $file\n" if $dl_debug;
337 sub dl_find_symbol_anywhere
341 foreach $libref (@dl_librefs) {
342 my $symref = dl_find_symbol($libref,$sym);
343 return $symref if $symref;
350 DynaLoader - Dynamically load C libraries into Perl code
352 dl_error(), dl_findfile(), dl_expandspec(), dl_load_file(), dl_find_symbol(), dl_find_symbol_anywhere(), dl_undef_symbols(), dl_install_xsub(), dl_load_flags(), bootstrap() - routines used by DynaLoader modules
358 @ISA = qw(... DynaLoader ...);
359 bootstrap YourPackage;
361 # optional method for 'global' loading
362 sub dl_load_flags { 0x01 }
367 This document defines a standard generic interface to the dynamic
368 linking mechanisms available on many platforms. Its primary purpose is
369 to implement automatic dynamic loading of Perl modules.
371 This document serves as both a specification for anyone wishing to
372 implement the DynaLoader for a new platform and as a guide for
373 anyone wishing to use the DynaLoader directly in an application.
375 The DynaLoader is designed to be a very simple high-level
376 interface that is sufficiently general to cover the requirements
377 of SunOS, HP-UX, NeXT, Linux, VMS and other platforms.
379 It is also hoped that the interface will cover the needs of OS/2, NT
380 etc and also allow pseudo-dynamic linking (using C<ld -A> at runtime).
382 It must be stressed that the DynaLoader, by itself, is practically
383 useless for accessing non-Perl libraries because it provides almost no
384 Perl-to-C 'glue'. There is, for example, no mechanism for calling a C
385 library function or supplying arguments. A C::DynaLib module
386 is available from CPAN sites which performs that function for some
389 DynaLoader Interface Summary
398 bootstrap($modulename) Perl
399 @filepaths = dl_findfile(@names) Perl
400 $flags = $modulename->dl_load_flags Perl
401 $symref = dl_find_symbol_anywhere($symbol) Perl
403 $libref = dl_load_file($filename, $flags) C
404 $symref = dl_find_symbol($libref, $symbol) C
405 @symbols = dl_undef_symbols() C
406 dl_install_xsub($name, $symref [, $filename]) C
407 $message = dl_error C
411 =item @dl_library_path
413 The standard/default list of directories in which dl_findfile() will
414 search for libraries etc. Directories are searched in order:
415 $dl_library_path[0], [1], ... etc
417 @dl_library_path is initialised to hold the list of 'normal' directories
418 (F</usr/lib>, etc) determined by B<Configure> (C<$Config{'libpth'}>). This should
419 ensure portability across a wide range of platforms.
421 @dl_library_path should also be initialised with any other directories
422 that can be determined from the environment at runtime (such as
423 LD_LIBRARY_PATH for SunOS).
425 After initialisation @dl_library_path can be manipulated by an
426 application using push and unshift before calling dl_findfile().
427 Unshift can be used to add directories to the front of the search order
428 either to save search time or to override libraries with the same name
429 in the 'normal' directories.
431 The load function that dl_load_file() calls may require an absolute
432 pathname. The dl_findfile() function and @dl_library_path can be
433 used to search for and return the absolute pathname for the
434 library/object that you wish to load.
436 =item @dl_resolve_using
438 A list of additional libraries or other shared objects which can be
439 used to resolve any undefined symbols that might be generated by a
440 later call to load_file().
442 This is only required on some platforms which do not handle dependent
443 libraries automatically. For example the Socket Perl extension
444 library (F<auto/Socket/Socket.so>) contains references to many socket
445 functions which need to be resolved when it's loaded. Most platforms
446 will automatically know where to find the 'dependent' library (e.g.,
447 F</usr/lib/libsocket.so>). A few platforms need to be told the
448 location of the dependent library explicitly. Use @dl_resolve_using
453 @dl_resolve_using = dl_findfile('-lsocket');
455 =item @dl_require_symbols
457 A list of one or more symbol names that are in the library/object file
458 to be dynamically loaded. This is only required on some platforms.
462 An array of the handles returned by successful calls to dl_load_file(),
463 made by bootstrap, in the order in which they were loaded.
464 Can be used with dl_find_symbol() to look for a symbol in any of
469 An array of module (package) names that have been bootstrap'ed.
475 $message = dl_error();
477 Error message text from the last failed DynaLoader function. Note
478 that, similar to errno in unix, a successful function call does not
481 Implementations should detect the error as soon as it occurs in any of
482 the other functions and save the corresponding message for later
483 retrieval. This will avoid problems on some platforms (such as SunOS)
484 where the error message is very temporary (e.g., dlerror()).
488 Internal debugging messages are enabled when $dl_debug is set true.
489 Currently setting $dl_debug only affects the Perl side of the
490 DynaLoader. These messages should help an application developer to
491 resolve any DynaLoader usage problems.
493 $dl_debug is set to C<$ENV{'PERL_DL_DEBUG'}> if defined.
495 For the DynaLoader developer/porter there is a similar debugging
496 variable added to the C code (see dlutils.c) and enabled if Perl was
497 built with the B<-DDEBUGGING> flag. This can also be set via the
498 PERL_DL_DEBUG environment variable. Set to 1 for minimal information or
505 @filepaths = dl_findfile(@names)
507 Determine the full paths (including file suffix) of one or more
508 loadable files given their generic names and optionally one or more
509 directories. Searches directories in @dl_library_path by default and
510 returns an empty list if no files were found.
512 Names can be specified in a variety of platform independent forms. Any
513 names in the form B<-lname> are converted into F<libname.*>, where F<.*> is
514 an appropriate suffix for the platform.
516 If a name does not already have a suitable prefix and/or suffix then
517 the corresponding file will be searched for by trying combinations of
518 prefix and suffix appropriate to the platform: "$name.o", "lib$name.*"
521 If any directories are included in @names they are searched before
522 @dl_library_path. Directories may be specified as B<-Ldir>. Any other
523 names are treated as filenames to be searched for.
525 Using arguments of the form C<-Ldir> and C<-lname> is recommended.
529 @dl_resolve_using = dl_findfile(qw(-L/usr/5lib -lposix));
532 =item dl_expandspec()
536 $filepath = dl_expandspec($spec)
538 Some unusual systems, such as VMS, require special filename handling in
539 order to deal with symbolic names for files (i.e., VMS's Logical Names).
541 To support these systems a dl_expandspec() function can be implemented
542 either in the F<dl_*.xs> file or code can be added to the autoloadable
543 dl_expandspec() function in F<DynaLoader.pm>. See F<DynaLoader.pm> for
550 $libref = dl_load_file($filename, $flags)
552 Dynamically load $filename, which must be the path to a shared object
553 or library. An opaque 'library reference' is returned as a handle for
554 the loaded object. Returns undef on error.
556 The $flags argument to alters dl_load_file behaviour.
559 0x01 make symbols available for linking later dl_load_file's.
560 (only known to work on Solaris 2 using dlopen(RTLD_GLOBAL))
561 (ignored under VMS; this is a normal part of image linking)
563 (On systems that provide a handle for the loaded object such as SunOS
564 and HPUX, $libref will be that handle. On other systems $libref will
565 typically be $filename or a pointer to a buffer containing $filename.
566 The application should not examine or alter $libref in any way.)
568 This is the function that does the real work. It should use the
569 current values of @dl_require_symbols and @dl_resolve_using if required.
571 SunOS: dlopen($filename)
572 HP-UX: shl_load($filename)
573 Linux: dld_create_reference(@dl_require_symbols); dld_link($filename)
574 NeXT: rld_load($filename, @dl_resolve_using)
575 VMS: lib$find_image_symbol($filename,$dl_require_symbols[0])
577 (The dlopen() function is also used by Solaris and some versions of
578 Linux, and is a common choice when providing a "wrapper" on other
579 mechanisms as is done in the OS/2 port.)
585 $flags = dl_loadflags $modulename;
587 Designed to be a method call, and to be overridden by a derived class
588 (i.e. a class which has DynaLoader in its @ISA). The definition in
589 DynaLoader itself returns 0, which produces standard behavior from
592 =item dl_find_symbol()
596 $symref = dl_find_symbol($libref, $symbol)
598 Return the address of the symbol $symbol or C<undef> if not found. If the
599 target system has separate functions to search for symbols of different
600 types then dl_find_symbol() should search for function symbols first and
603 The exact manner in which the address is returned in $symref is not
604 currently defined. The only initial requirement is that $symref can
605 be passed to, and understood by, dl_install_xsub().
607 SunOS: dlsym($libref, $symbol)
608 HP-UX: shl_findsym($libref, $symbol)
609 Linux: dld_get_func($symbol) and/or dld_get_symbol($symbol)
610 NeXT: rld_lookup("_$symbol")
611 VMS: lib$find_image_symbol($libref,$symbol)
614 =item dl_find_symbol_anywhere()
618 $symref = dl_find_symbol_anywhere($symbol)
620 Applies dl_find_symbol() to the members of @dl_librefs and returns
621 the first match found.
623 =item dl_undef_symbols()
627 @symbols = dl_undef_symbols()
629 Return a list of symbol names which remain undefined after load_file().
630 Returns C<()> if not known. Don't worry if your platform does not provide
631 a mechanism for this. Most do not need it and hence do not provide it,
632 they just return an empty list.
635 =item dl_install_xsub()
639 dl_install_xsub($perl_name, $symref [, $filename])
641 Create a new Perl external subroutine named $perl_name using $symref as
642 a pointer to the function which implements the routine. This is simply
643 a direct call to newXSUB(). Returns a reference to the installed
646 The $filename parameter is used by Perl to identify the source file for
647 the function if required by die(), caller() or the debugger. If
648 $filename is not defined then "DynaLoader" will be used.
657 This is the normal entry point for automatic dynamic loading in Perl.
659 It performs the following actions:
665 locates an auto/$module directory by searching @INC
669 uses dl_findfile() to determine the filename to load
673 sets @dl_require_symbols to C<("boot_$module")>
677 executes an F<auto/$module/$module.bs> file if it exists
678 (typically used to add to @dl_resolve_using any files which
679 are required to load the module on the current platform)
683 calls dl_load_flags() to determine how to load the file.
687 calls dl_load_file() to load the file
691 calls dl_undef_symbols() and warns if any symbols are undefined
695 calls dl_find_symbol() for "boot_$module"
699 calls dl_install_xsub() to install it as "${module}::bootstrap"
703 calls &{"${module}::bootstrap"} to bootstrap the module (actually
704 it uses the function reference returned by dl_install_xsub for speed)
713 Tim Bunce, 11 August 1994.
715 This interface is based on the work and comments of (in no particular
716 order): Larry Wall, Robert Sanders, Dean Roehrich, Jeff Okamoto, Anno
717 Siegel, Thomas Neumann, Paul Marquess, Charles Bailey, myself and others.
719 Larry Wall designed the elegant inherited bootstrap mechanism and
720 implemented the first Perl 5 dynamic loader using it.
722 Solaris global loading added by Nick Ing-Simmons with design/coding
723 assistance from Tim Bunce, January 1996.