1 # $Id: Storable.pm,v 1.0.1.13 2001/12/01 13:34:49 ram Exp $
3 # Copyright (c) 1995-2000, Raphael Manfredi
5 # You may redistribute only under the same terms as Perl 5, as specified
6 # in the README file that comes with the distribution.
11 package Storable; @ISA = qw(Exporter DynaLoader);
13 @EXPORT = qw(store retrieve);
15 nstore store_fd nstore_fd fd_retrieve
19 lock_store lock_nstore lock_retrieve
23 use vars qw($canonical $forgive_me $VERSION);
26 *AUTOLOAD = \&AutoLoader::AUTOLOAD; # Grrr...
29 # Use of Log::Agent is optional
32 eval "use Log::Agent";
37 # They might miss :flock in Fcntl
41 if (eval { require Fcntl; 1 } && exists $Fcntl::EXPORT_TAGS{'flock'}) {
42 Fcntl->import(':flock');
51 # Can't Autoload cleanly as this clashes 8.3 with &retrieve
52 sub retrieve_fd { &fd_retrieve } # Backward compatibility
54 # By default restricted hashes are downgraded on earlier perls.
56 $Storable::downgrade_restricted = 1;
57 $Storable::accept_future_minor = 1;
62 # Use of Log::Agent is optional. If it hasn't imported these subs then
63 # Autoloader will kindly supply our fallback implementation.
75 # Determine whether locking is possible, but only when needed.
78 sub CAN_FLOCK; my $CAN_FLOCK; sub CAN_FLOCK {
79 return $CAN_FLOCK if defined $CAN_FLOCK;
80 require Config; import Config;
83 $Config{'d_fcntl_can_lock'} ||
90 # To recognize the data files of the Perl module Storable,
91 # the following lines need to be added to the local magic(5) file,
92 # usually either /usr/share/misc/magic or /etc/magic.
94 0 string perl-store perl Storable(v0.6) data
95 >4 byte >0 (net-order %d)
96 >>4 byte &01 (network-ordered)
100 0 string pst0 perl Storable(v0.7) data
102 >>4 byte &01 (network-ordered)
103 >>4 byte =5 (major 2)
104 >>4 byte =4 (major 2)
105 >>5 byte >0 (minor %d)
111 return unless defined $header and length $header > 11;
113 if ($header =~ s/^perl-store//) {
114 die "Can't deal with version 0 headers";
115 } elsif ($header =~ s/^pst0//) {
118 # Assume it's a string.
119 my ($major, $minor, $bytelen) = unpack "C3", $header;
121 my $net_order = $major & 1;
123 @$result{qw(major minor netorder)} = ($major, $minor, $net_order);
125 return $result if $net_order;
127 # I assume that it is rare to find v1 files, so this is an intentionally
128 # inefficient way of doing it, to make the rest of the code constant.
130 delete $result->{minor};
131 $header = '.' . $header;
135 @$result{qw(byteorder intsize longsize ptrsize)} =
136 unpack "x3 A$bytelen C3", $header;
138 if ($major >= 2 and $minor >= 2) {
139 $result->{nvsize} = unpack "x6 x$bytelen C", $header;
147 # Store target object hierarchy, identified by a reference to its root.
148 # The stored object tree may later be retrieved to memory via retrieve.
149 # Returns undef if an I/O error occurred, in which case the file is
153 return _store(\&pstore, @_, 0);
159 # Same as store, but in network order.
162 return _store(\&net_pstore, @_, 0);
168 # Same as store, but flock the file first (advisory locking).
171 return _store(\&pstore, @_, 1);
177 # Same as nstore, but flock the file first (advisory locking).
180 return _store(\&net_pstore, @_, 1);
183 # Internal store to file routine
187 my ($file, $use_locking) = @_;
188 logcroak "not a reference" unless ref($self);
189 logcroak "wrong argument number" unless @_ == 2; # No @foo in arglist
192 open(FILE, ">>$file") || logcroak "can't write into $file: $!";
193 unless (&CAN_FLOCK) {
194 logcarp "Storable::lock_store: fcntl/flock emulation broken on $^O";
197 flock(FILE, LOCK_EX) ||
198 logcroak "can't get exclusive lock on $file: $!";
200 # Unlocking will happen when FILE is closed
202 open(FILE, ">$file") || logcroak "can't create $file: $!";
204 binmode FILE; # Archaic systems...
205 my $da = $@; # Don't mess if called from exception handler
207 # Call C routine nstore or pstore, depending on network order
208 eval { $ret = &$xsptr(*FILE, $self) };
209 close(FILE) or $ret = undef;
210 unlink($file) or warn "Can't unlink $file: $!\n" if $@ || !defined $ret;
211 logcroak $@ if $@ =~ s/\.?\n$/,/;
213 return $ret ? $ret : undef;
219 # Same as store, but perform on an already opened file descriptor instead.
220 # Returns undef if an I/O error occurred.
223 return _store_fd(\&pstore, @_);
229 # Same as store_fd, but in network order.
232 my ($self, $file) = @_;
233 return _store_fd(\&net_pstore, @_);
236 # Internal store routine on opened file descriptor
241 logcroak "not a reference" unless ref($self);
242 logcroak "too many arguments" unless @_ == 1; # No @foo in arglist
243 my $fd = fileno($file);
244 logcroak "not a valid file descriptor" unless defined $fd;
245 my $da = $@; # Don't mess if called from exception handler
247 # Call C routine nstore or pstore, depending on network order
248 eval { $ret = &$xsptr($file, $self) };
249 logcroak $@ if $@ =~ s/\.?\n$/,/;
250 local $\; print $file ''; # Autoflush the file if wanted
252 return $ret ? $ret : undef;
258 # Store oject and its hierarchy in memory and return a scalar
259 # containing the result.
262 _freeze(\&mstore, @_);
268 # Same as freeze but in network order.
271 _freeze(\&net_mstore, @_);
274 # Internal freeze routine
278 logcroak "not a reference" unless ref($self);
279 logcroak "too many arguments" unless @_ == 0; # No @foo in arglist
280 my $da = $@; # Don't mess if called from exception handler
282 # Call C routine mstore or net_mstore, depending on network order
283 eval { $ret = &$xsptr($self) };
284 logcroak $@ if $@ =~ s/\.?\n$/,/;
286 return $ret ? $ret : undef;
292 # Retrieve object hierarchy from disk, returning a reference to the root
293 # object of that tree.
302 # Same as retrieve, but with advisory locking.
308 # Internal retrieve routine
310 my ($file, $use_locking) = @_;
312 open(FILE, $file) || logcroak "can't open $file: $!";
313 binmode FILE; # Archaic systems...
315 my $da = $@; # Could be from exception handler
317 unless (&CAN_FLOCK) {
318 logcarp "Storable::lock_store: fcntl/flock emulation broken on $^O";
321 flock(FILE, LOCK_SH) || logcroak "can't get shared lock on $file: $!";
322 # Unlocking will happen when FILE is closed
324 eval { $self = pretrieve(*FILE) }; # Call C routine
326 logcroak $@ if $@ =~ s/\.?\n$/,/;
334 # Same as retrieve, but perform from an already opened file descriptor instead.
338 my $fd = fileno($file);
339 logcroak "not a valid file descriptor" unless defined $fd;
341 my $da = $@; # Could be from exception handler
342 eval { $self = pretrieve($file) }; # Call C routine
343 logcroak $@ if $@ =~ s/\.?\n$/,/;
351 # Recreate objects in memory from an existing frozen image created
352 # by freeze. If the frozen image passed is undef, return undef.
356 return undef unless defined $frozen;
358 my $da = $@; # Could be from exception handler
359 eval { $self = mretrieve($frozen) }; # Call C routine
360 logcroak $@ if $@ =~ s/\.?\n$/,/;
367 Storable - persistence for Perl data structures
372 store \%table, 'file';
373 $hashref = retrieve('file');
375 use Storable qw(nstore store_fd nstore_fd freeze thaw dclone);
378 nstore \%table, 'file';
379 $hashref = retrieve('file'); # There is NO nretrieve()
381 # Storing to and retrieving from an already opened file
382 store_fd \@array, \*STDOUT;
383 nstore_fd \%table, \*STDOUT;
384 $aryref = fd_retrieve(\*SOCKET);
385 $hashref = fd_retrieve(\*SOCKET);
387 # Serializing to memory
388 $serialized = freeze \%table;
389 %table_clone = %{ thaw($serialized) };
391 # Deep (recursive) cloning
392 $cloneref = dclone($ref);
395 use Storable qw(lock_store lock_nstore lock_retrieve)
396 lock_store \%table, 'file';
397 lock_nstore \%table, 'file';
398 $hashref = lock_retrieve('file');
402 The Storable package brings persistence to your Perl data structures
403 containing SCALAR, ARRAY, HASH or REF objects, i.e. anything that can be
404 conveniently stored to disk and retrieved at a later time.
406 It can be used in the regular procedural way by calling C<store> with
407 a reference to the object to be stored, along with the file name where
408 the image should be written.
410 The routine returns C<undef> for I/O problems or other internal error,
411 a true value otherwise. Serious errors are propagated as a C<die> exception.
413 To retrieve data stored to disk, use C<retrieve> with a file name.
414 The objects stored into that file are recreated into memory for you,
415 and a I<reference> to the root object is returned. In case an I/O error
416 occurs while reading, C<undef> is returned instead. Other serious
417 errors are propagated via C<die>.
419 Since storage is performed recursively, you might want to stuff references
420 to objects that share a lot of common data into a single array or hash
421 table, and then store that object. That way, when you retrieve back the
422 whole thing, the objects will continue to share what they originally shared.
424 At the cost of a slight header overhead, you may store to an already
425 opened file descriptor using the C<store_fd> routine, and retrieve
426 from a file via C<fd_retrieve>. Those names aren't imported by default,
427 so you will have to do that explicitly if you need those routines.
428 The file descriptor you supply must be already opened, for read
429 if you're going to retrieve and for write if you wish to store.
431 store_fd(\%table, *STDOUT) || die "can't store to stdout\n";
432 $hashref = fd_retrieve(*STDIN);
434 You can also store data in network order to allow easy sharing across
435 multiple platforms, or when storing on a socket known to be remotely
436 connected. The routines to call have an initial C<n> prefix for I<network>,
437 as in C<nstore> and C<nstore_fd>. At retrieval time, your data will be
438 correctly restored so you don't have to know whether you're restoring
439 from native or network ordered data. Double values are stored stringified
440 to ensure portability as well, at the slight risk of loosing some precision
441 in the last decimals.
443 When using C<fd_retrieve>, objects are retrieved in sequence, one
444 object (i.e. one recursive tree) per associated C<store_fd>.
446 If you're more from the object-oriented camp, you can inherit from
447 Storable and directly store your objects by invoking C<store> as
448 a method. The fact that the root of the to-be-stored tree is a
449 blessed reference (i.e. an object) is special-cased so that the
450 retrieve does not provide a reference to that object but rather the
451 blessed object reference itself. (Otherwise, you'd get a reference
452 to that blessed object).
456 The Storable engine can also store data into a Perl scalar instead, to
457 later retrieve them. This is mainly used to freeze a complex structure in
458 some safe compact memory place (where it can possibly be sent to another
459 process via some IPC, since freezing the structure also serializes it in
460 effect). Later on, and maybe somewhere else, you can thaw the Perl scalar
461 out and recreate the original complex structure in memory.
463 Surprisingly, the routines to be called are named C<freeze> and C<thaw>.
464 If you wish to send out the frozen scalar to another machine, use
465 C<nfreeze> instead to get a portable image.
467 Note that freezing an object structure and immediately thawing it
468 actually achieves a deep cloning of that structure:
470 dclone(.) = thaw(freeze(.))
472 Storable provides you with a C<dclone> interface which does not create
473 that intermediary scalar but instead freezes the structure in some
474 internal memory space and then immediately thaws it out.
476 =head1 ADVISORY LOCKING
478 The C<lock_store> and C<lock_nstore> routine are equivalent to
479 C<store> and C<nstore>, except that they get an exclusive lock on
480 the file before writing. Likewise, C<lock_retrieve> does the same
481 as C<retrieve>, but also gets a shared lock on the file before reading.
483 As with any advisory locking scheme, the protection only works if you
484 systematically use C<lock_store> and C<lock_retrieve>. If one side of
485 your application uses C<store> whilst the other uses C<lock_retrieve>,
486 you will get no protection at all.
488 The internal advisory locking is implemented using Perl's flock()
489 routine. If your system does not support any form of flock(), or if
490 you share your files across NFS, you might wish to use other forms
491 of locking by using modules such as LockFile::Simple which lock a
492 file using a filesystem entry, instead of locking the file descriptor.
496 The heart of Storable is written in C for decent speed. Extra low-level
497 optimizations have been made when manipulating perl internals, to
498 sacrifice encapsulation for the benefit of greater speed.
500 =head1 CANONICAL REPRESENTATION
502 Normally, Storable stores elements of hashes in the order they are
503 stored internally by Perl, i.e. pseudo-randomly. If you set
504 C<$Storable::canonical> to some C<TRUE> value, Storable will store
505 hashes with the elements sorted by their key. This allows you to
506 compare data structures by comparing their frozen representations (or
507 even the compressed frozen representations), which can be useful for
508 creating lookup tables for complicated queries.
510 Canonical order does not imply network order; those are two orthogonal
513 =head1 FORWARD COMPATIBILITY
515 This release of Storable can be used on a newer version of Perl to
516 serialize data which is not supported by earlier Perls. By default,
517 Storable will attempt to do the right thing, by C<croak()>ing if it
518 encounters data that it cannot deserialize. However, the defaults
519 can be changed as follows:
525 Perl 5.6 added support for Unicode characters with code points > 255,
526 and Perl 5.8 has full support for Unicode characters in hash keys.
527 Perl internally encodes strings with these characters using utf8, and
528 Storable serializes them as utf8. By default, if an older version of
529 Perl encounters a utf8 value it cannot represent, it will C<croak()>.
530 To change this behaviour so that Storable deserializes utf8 encoded
531 values as the string of bytes (effectively dropping the I<is_utf8> flag)
532 set C<$Storable::drop_utf8> to some C<TRUE> value. This is a form of
533 data loss, because with C<$drop_utf8> true, it becomes impossible to tell
534 whether the original data was the Unicode string, or a series of bytes
535 that happen to be valid utf8.
537 =item restricted hashes
539 Perl 5.8 adds support for restricted hashes, which have keys
540 restricted to a given set, and can have values locked to be read only.
541 By default, when Storable encounters a restricted hash on a perl
542 that doesn't support them, it will deserialize it as a normal hash,
543 silently discarding any placeholder keys and leaving the keys and
544 all values unlocked. To make Storable C<croak()> instead, set
545 C<$Storable::downgrade_restricted> to a C<FALSE> value. To restore
546 the default set it back to some C<TRUE> value.
548 =item files from future versions of Storable
550 Earlier versions of Storable would immediately croak if they encountered
551 a file with a higher internal version number than the reading Storable
552 knew about. Internal version numbers are increased each time new data
553 types (such as restricted hashes) are added to the vocabulary of the file
554 format. This meant that a newer Storable module had no way of writing a
555 file readable by an older Storable, even if the writer didn't store newer
558 This version of Storable will defer croaking until it encounters a data
559 type in the file that it does not recognize. This means that it will
560 continue to read files generated by newer Storable modules which are careful
561 in what they write out, making it easier to upgrade Storable modules in a
564 The old behaviour of immediate croaking can be re-instated by setting
565 C<$Storable::accept_future_minor> to some C<FALSE> value.
569 All these variables have no effect on a newer Perl which supports the
572 =head1 ERROR REPORTING
574 Storable uses the "exception" paradigm, in that it does not try to workaround
575 failures: if something bad happens, an exception is generated from the
576 caller's perspective (see L<Carp> and C<croak()>). Use eval {} to trap
579 When Storable croaks, it tries to report the error via the C<logcroak()>
580 routine from the C<Log::Agent> package, if it is available.
582 Normal errors are reported by having store() or retrieve() return C<undef>.
583 Such errors are usually I/O errors (or truncated stream errors at retrieval).
589 Any class may define hooks that will be called during the serialization
590 and deserialization process on objects that are instances of that class.
591 Those hooks can redefine the way serialization is performed (and therefore,
592 how the symmetrical deserialization should be conducted).
594 Since we said earlier:
596 dclone(.) = thaw(freeze(.))
598 everything we say about hooks should also hold for deep cloning. However,
599 hooks get to know whether the operation is a mere serialization, or a cloning.
601 Therefore, when serializing hooks are involved,
603 dclone(.) <> thaw(freeze(.))
605 Well, you could keep them in sync, but there's no guarantee it will always
606 hold on classes somebody else wrote. Besides, there is little to gain in
607 doing so: a serializing hook could keep only one attribute of an object,
608 which is probably not what should happen during a deep cloning of that
611 Here is the hooking interface:
615 =item C<STORABLE_freeze> I<obj>, I<cloning>
617 The serializing hook, called on the object during serialization. It can be
618 inherited, or defined in the class itself, like any other method.
620 Arguments: I<obj> is the object to serialize, I<cloning> is a flag indicating
621 whether we're in a dclone() or a regular serialization via store() or freeze().
623 Returned value: A LIST C<($serialized, $ref1, $ref2, ...)> where $serialized
624 is the serialized form to be used, and the optional $ref1, $ref2, etc... are
625 extra references that you wish to let the Storable engine serialize.
627 At deserialization time, you will be given back the same LIST, but all the
628 extra references will be pointing into the deserialized structure.
630 The B<first time> the hook is hit in a serialization flow, you may have it
631 return an empty list. That will signal the Storable engine to further
632 discard that hook for this class and to therefore revert to the default
633 serialization of the underlying Perl data. The hook will again be normally
634 processed in the next serialization.
636 Unless you know better, serializing hook should always say:
638 sub STORABLE_freeze {
639 my ($self, $cloning) = @_;
640 return if $cloning; # Regular default serialization
644 in order to keep reasonable dclone() semantics.
646 =item C<STORABLE_thaw> I<obj>, I<cloning>, I<serialized>, ...
648 The deserializing hook called on the object during deserialization.
649 But wait: if we're deserializing, there's no object yet... right?
651 Wrong: the Storable engine creates an empty one for you. If you know Eiffel,
652 you can view C<STORABLE_thaw> as an alternate creation routine.
654 This means the hook can be inherited like any other method, and that
655 I<obj> is your blessed reference for this particular instance.
657 The other arguments should look familiar if you know C<STORABLE_freeze>:
658 I<cloning> is true when we're part of a deep clone operation, I<serialized>
659 is the serialized string you returned to the engine in C<STORABLE_freeze>,
660 and there may be an optional list of references, in the same order you gave
661 them at serialization time, pointing to the deserialized objects (which
662 have been processed courtesy of the Storable engine).
664 When the Storable engine does not find any C<STORABLE_thaw> hook routine,
665 it tries to load the class by requiring the package dynamically (using
666 the blessed package name), and then re-attempts the lookup. If at that
667 time the hook cannot be located, the engine croaks. Note that this mechanism
668 will fail if you define several classes in the same file, but L<perlmod>
671 It is up to you to use this information to populate I<obj> the way you want.
673 Returned value: none.
679 Predicates are not exportable. They must be called by explicitly prefixing
680 them with the Storable package name.
684 =item C<Storable::last_op_in_netorder>
686 The C<Storable::last_op_in_netorder()> predicate will tell you whether
687 network order was used in the last store or retrieve operation. If you
688 don't know how to use this, just forget about it.
690 =item C<Storable::is_storing>
692 Returns true if within a store operation (via STORABLE_freeze hook).
694 =item C<Storable::is_retrieving>
696 Returns true if within a retrieve operation (via STORABLE_thaw hook).
702 With hooks comes the ability to recurse back to the Storable engine.
703 Indeed, hooks are regular Perl code, and Storable is convenient when
704 it comes to serializing and deserializing things, so why not use it
705 to handle the serialization string?
707 There are a few things you need to know, however:
713 You can create endless loops if the things you serialize via freeze()
714 (for instance) point back to the object we're trying to serialize in
719 Shared references among objects will not stay shared: if we're serializing
720 the list of object [A, C] where both object A and C refer to the SAME object
721 B, and if there is a serializing hook in A that says freeze(B), then when
722 deserializing, we'll get [A', C'] where A' refers to B', but C' refers to D,
723 a deep clone of B'. The topology was not preserved.
727 That's why C<STORABLE_freeze> lets you provide a list of references
728 to serialize. The engine guarantees that those will be serialized in the
729 same context as the other objects, and therefore that shared objects will
732 In the above [A, C] example, the C<STORABLE_freeze> hook could return:
734 ("something", $self->{B})
736 and the B part would be serialized by the engine. In C<STORABLE_thaw>, you
737 would get back the reference to the B' object, deserialized for you.
739 Therefore, recursion should normally be avoided, but is nonetheless supported.
743 There is a Clone module available on CPAN which implements deep cloning
744 natively, i.e. without freezing to memory and thawing the result. It is
745 aimed to replace Storable's dclone() some day. However, it does not currently
746 support Storable hooks to redefine the way deep cloning is performed.
748 =head1 Storable magic
750 Yes, there's a lot of that :-) But more precisely, in UNIX systems
751 there's a utility called C<file>, which recognizes data files based on
752 their contents (usually their first few bytes). For this to work,
753 a certain file called F<magic> needs to taught about the I<signature>
754 of the data. Where that configuration file lives depends on the UNIX
755 flavour; often it's something like F</usr/share/misc/magic> or
756 F</etc/magic>. Your system administrator needs to do the updating of
757 the F<magic> file. The necessary signature information is output to
758 STDOUT by invoking Storable::show_file_magic(). Note that the GNU
759 implementation of the C<file> utility, version 3.38 or later,
760 is expected to contain support for recognising Storable files
761 out-of-the-box, in addition to other kinds of Perl files.
765 Here are some code samples showing a possible usage of Storable:
767 use Storable qw(store retrieve freeze thaw dclone);
769 %color = ('Blue' => 0.1, 'Red' => 0.8, 'Black' => 0, 'White' => 1);
771 store(\%color, '/tmp/colors') or die "Can't store %a in /tmp/colors!\n";
773 $colref = retrieve('/tmp/colors');
774 die "Unable to retrieve from /tmp/colors!\n" unless defined $colref;
775 printf "Blue is still %lf\n", $colref->{'Blue'};
777 $colref2 = dclone(\%color);
779 $str = freeze(\%color);
780 printf "Serialization of %%color is %d bytes long.\n", length($str);
781 $colref3 = thaw($str);
783 which prints (on my machine):
785 Blue is still 0.100000
786 Serialization of %color is 102 bytes long.
790 If you're using references as keys within your hash tables, you're bound
791 to be disappointed when retrieving your data. Indeed, Perl stringifies
792 references used as hash table keys. If you later wish to access the
793 items via another reference stringification (i.e. using the same
794 reference that was used for the key originally to record the value into
795 the hash table), it will work because both references stringify to the
798 It won't work across a sequence of C<store> and C<retrieve> operations,
799 however, because the addresses in the retrieved objects, which are
800 part of the stringified references, will probably differ from the
801 original addresses. The topology of your structure is preserved,
802 but not hidden semantics like those.
804 On platforms where it matters, be sure to call C<binmode()> on the
805 descriptors that you pass to Storable functions.
807 Storing data canonically that contains large hashes can be
808 significantly slower than storing the same data normally, as
809 temporary arrays to hold the keys for each hash have to be allocated,
810 populated, sorted and freed. Some tests have shown a halving of the
811 speed of storing -- the exact penalty will depend on the complexity of
812 your data. There is no slowdown on retrieval.
816 You can't store GLOB, CODE, FORMLINE, etc.... If you can define
817 semantics for those operations, feel free to enhance Storable so that
818 it can deal with them.
820 The store functions will C<croak> if they run into such references
821 unless you set C<$Storable::forgive_me> to some C<TRUE> value. In that
822 case, the fatal message is turned in a warning and some
823 meaningless string is stored instead.
825 Setting C<$Storable::canonical> may not yield frozen strings that
826 compare equal due to possible stringification of numbers. When the
827 string version of a scalar exists, it is the form stored; therefore,
828 if you happen to use your numbers as strings between two freezing
829 operations on the same data structures, you will get different
832 When storing doubles in network order, their value is stored as text.
833 However, you should also not expect non-numeric floating-point values
834 such as infinity and "not a number" to pass successfully through a
835 nstore()/retrieve() pair.
837 As Storable neither knows nor cares about character sets (although it
838 does know that characters may be more than eight bits wide), any difference
839 in the interpretation of character codes between a host and a target
840 system is your problem. In particular, if host and target use different
841 code points to represent the characters used in the text representation
842 of floating-point numbers, you will not be able be able to exchange
843 floating-point data, even with nstore().
845 C<Storable::drop_utf8> is a blunt tool. There is no facility either to
846 return B<all> strings as utf8 sequences, or to attempt to convert utf8
847 data back to 8 bit and C<croak()> if the conversion fails.
851 Thank you to (in chronological order):
853 Jarkko Hietaniemi <jhi@iki.fi>
854 Ulrich Pfeifer <pfeifer@charly.informatik.uni-dortmund.de>
855 Benjamin A. Holzman <bah@ecnvantage.com>
856 Andrew Ford <A.Ford@ford-mason.co.uk>
857 Gisle Aas <gisle@aas.no>
858 Jeff Gresham <gresham_jeffrey@jpmorgan.com>
859 Murray Nesbitt <murray@activestate.com>
860 Marc Lehmann <pcg@opengroup.org>
861 Justin Banks <justinb@wamnet.com>
862 Jarkko Hietaniemi <jhi@iki.fi> (AGAIN, as perl 5.7.0 Pumpkin!)
863 Salvador Ortiz Garcia <sog@msg.com.mx>
864 Dominic Dunlop <domo@computer.org>
865 Erik Haugan <erik@solbors.no>
867 for their bug reports, suggestions and contributions.
869 Benjamin Holzman contributed the tied variable support, Andrew Ford
870 contributed the canonical order for hashes, and Gisle Aas fixed
871 a few misunderstandings of mine regarding the perl internals,
872 and optimized the emission of "tags" in the output streams by
873 simply counting the objects instead of tagging them (leading to
874 a binary incompatibility for the Storable image starting at version
875 0.6--older images are, of course, still properly understood).
876 Murray Nesbitt made Storable thread-safe. Marc Lehmann added overloading
877 and references to tied items support.
881 Storable was written by Raphael Manfredi F<E<lt>Raphael_Manfredi@pobox.comE<gt>>
882 Maintenance is now done by the perl5-porters F<E<lt>perl5-porters@perl.orgE<gt>>
884 Please e-mail us with problems, bug fixes, comments and complaints,
885 although if you have complements you should send them to Raphael.
886 Please don't e-mail Raphael with problems, as he no longer works on
887 Storable, and your message will be delayed while he forwards it to us.