1 package threads::shared;
9 unless ($Config{useithreads}) {
10 my @caller = caller(2);
12 $caller[1] line $caller[2]:
14 This Perl hasn't been configured and built properly for the threads
15 module to work. (The 'useithreads' configuration option hasn't been used.)
17 Having threads support requires all of Perl and all of the modules in
18 the Perl installation to be rebuilt, it is not just a question of adding
19 the threads module. (In other words, threaded and non-threaded Perls
20 are binary incompatible.)
22 If you want to the use the threads module, please contact the people
25 Cannot continue, aborting.
31 our @ISA = qw(Exporter);
32 our @EXPORT = qw(share cond_wait cond_broadcast cond_signal _refcnt _id _thrcnt);
33 our $VERSION = '0.90';
35 use Attribute::Handlers;
38 if ($Config{'useithreads'}) {
39 *cond_wait = \&cond_wait_enabled;
40 *cond_signal = \&cond_signal_enabled;
41 *cond_broadcast = \&cond_broadcast_enabled;
43 XSLoader::load('threads::shared',$VERSION);
46 *share = \&share_disabled;
47 *cond_wait = \&cond_wait_disabled;
48 *cond_signal = \&cond_signal_disabled;
49 *cond_broadcast = \&cond_broadcast_disabled;
53 sub cond_wait_disabled { return @_ };
54 sub cond_signal_disabled { return @_};
55 sub cond_broadcast_disabled { return @_};
56 sub share_disabled { return @_}
58 $threads::shared::threads_shared = 1;
62 sub threads::shared::tie::SPLICE
64 die "Splice not implemented for shared arrays";
67 sub UNIVERSAL::shared : ATTR {
68 my ($package, $symbol, $referent, $attr, $data, $phase) = @_;
76 threads::shared - Perl extension for sharing data structures between threads
83 my($scalar, @array, %hash);
88 $hash{bar} = share({});
93 cond_broadcast(@array);
98 This modules allows you to share() variables. These variables will
99 then be shared across different threads (and pseudoforks on
100 win32). They are used together with the threads module.
104 C<share>, C<lock>, C<unlock>, C<cond_wait>, C<cond_signal>, C<cond_broadcast>
112 C<share> takes a value and marks it as shared. You can share a scalar, array,
113 hash, scalar ref, array ref or hash ref. C<share> will return the shared value.
115 C<share> will traverse up references exactly I<one> level.
116 C<share(\$a)> is equivalent to C<share($a)>, while C<share(\\$a)> is not.
120 C<lock> places a lock on a variable until the lock goes out of scope. If
121 the variable is locked by another thread, the C<lock> call will block until
122 it's available. C<lock> is recursive, so multiple calls to C<lock> are
123 safe -- the variable will remain locked until the outermost lock on the
124 variable goes out of scope or C<unlock> is called enough times to match
125 the number of calls to <lock>.
127 If a container object, such as a hash or array, is locked, all the elements
128 of that container are not locked. For example, if a thread does a C<lock
129 @a>, any other thread doing a C<lock($a[12])> won't block.
131 C<lock> will traverse up references exactly I<one> level.
132 C<lock(\$a)> is equivalent to C<lock($a)>, while C<lock(\\$a)> is not.
135 =item unlock VARIABLE
137 C<unlock> takes a B<locked> variable and decrements the lock count.
138 If the lock count is zero the variable is unlocked. It is not necessary
139 to call C<unlock> but it can be useful to reduce lock contention.
141 C<unlock> will traverse up references exactly I<one> level.
142 C<unlock(\$a)> is equivalent to C<unlock($a)>, while C<unlock(\\$a)> is not.
144 =item cond_wait VARIABLE
146 The C<cond_wait> function takes a B<locked> variable as a parameter,
147 unlocks the variable, and blocks until another thread does a C<cond_signal>
148 or C<cond_broadcast> for that same locked variable. The variable that
149 C<cond_wait> blocked on is relocked after the C<cond_wait> is satisfied.
150 If there are multiple threads C<cond_wait>ing on the same variable, all but
151 one will reblock waiting to reacquire the lock on the variable. (So if
152 you're only using C<cond_wait> for synchronization, give up the lock as
155 It is important to note that the variable can be notified even if no
156 thread C<cond_signal> or C<cond_broadcast> on the variable. It is therefore
157 important to check the value of the variable and go back to waiting if the
158 requirement is not fulfilled.
160 =item cond_signal VARIABLE
162 The C<cond_signal> function takes a B<locked> variable as a parameter and
163 unblocks one thread that's C<cond_wait>ing on that variable. If more than
164 one thread is blocked in a C<cond_wait> on that variable, only one (and
165 which one is indeterminate) will be unblocked.
167 If there are no threads blocked in a C<cond_wait> on the variable, the
170 =item cond_broadcast VARIABLE
172 The C<cond_broadcast> function works similarly to C<cond_signal>.
173 C<cond_broadcast>, though, will unblock B<all> the threads that are blocked
174 in a C<cond_wait> on the locked variable, rather than only one.
180 threads::shared is designed to disable itself silently if threads are
181 not available. If you want access to threads, you must C<use threads>
182 before you C<use threads::shared>. threads will emit a warning if you
183 use it after threads::shared.
187 C<bless> is not supported on shared references. In the current version,
188 C<bless> will only bless the thread local reference and the blessing
189 will not propagate to the other threads. This is expected to be
190 implemented in a future version of Perl.
192 Does not support splice on arrays!
196 Arthur Bergman E<lt>arthur at contiller.seE<gt>
198 threads::shared is released under the same license as Perl
200 Documentation borrowed from Thread.pm