9 unless ($Config{useithreads}) {
10 my @caller = caller(2);
12 $caller[1] line $caller[2]:
14 This Perl hasn't been configured and built properly for the threads
15 module to work. (The 'useithreads' configuration option hasn't been used.)
17 Having threads support requires all of Perl and all of the modules in
18 the Perl installation to be rebuilt, it is not just a question of adding
19 the threads module. (In other words, threaded and non-threaded Perls
20 are binary incompatible.)
22 If you want to the use the threads module, please contact the people
25 Cannot continue, aborting.
37 warn "Warning, threads::shared has already been loaded. ".
38 "To enable shared variables for these modules 'use threads' ".
39 "must be called before any of those modules are loaded\n"
40 if($threads::shared::threads_shared);
46 our @ISA = qw(Exporter DynaLoader);
48 our %EXPORT_TAGS = ( all => [qw(yield)]);
50 our @EXPORT_OK = ( @{ $EXPORT_TAGS{'all'} } );
55 our $VERSION = '0.99';
59 return 1 if($_[0]->tid() == $_[1]->tid());
65 return threads->new($cref,@_);
68 $threads::threads = 1;
70 bootstrap threads $VERSION;
72 # why document 'new' then use 'create' in the tests!
75 # Preloaded methods go here.
82 threads - Perl extension allowing use of interpreter based threads from perl
89 print "Thread started\n";
92 my $thread = threads->create("start_thread","argument");
94 $thread->create(sub { print "I am a thread"},"argument");
100 $thread = threads->self();
103 threads->self->tid();
113 Perl 5.6 introduced something called interpreter threads. Interpreter
114 threads are different from "5005threads" (the thread model of Perl
115 5.005) by creating a new perl interpreter per thread and not sharing
116 any data or state between threads.
118 Prior to perl 5.8 this has only been available to people embedding
119 perl and for emulating fork() on windows.
121 The threads API is loosely based on the old Thread.pm API. It is very
122 important to note that variables are not shared between threads, all
123 variables are per default thread local. To use shared variables one
124 must use threads::shared.
126 It is also important to note that you preferably enable threads by
127 doing C<use threads> as early as possible and that it is not possible
128 to enable threading inside an eval ""; In particular, if you are
129 intending to share variables with threads::shared, you must
130 C<use threads> before you C<use threads::shared> and threads will emit
131 a warning if you do it the other way around.
135 =item $thread = threads->create(function, LIST)
137 This will create a new thread with the entry point function and give
138 it LIST as parameters. It will return the corresponding threads
143 This will wait for the corresponding thread to join. When it finishes
144 join will return the return values of the entry point function. If a
145 thread has been detached, an error will be thrown..
147 =item $thread->detach
149 Will throw away the return value from the thread and make it
154 This will return the object for the current thread.
158 This will return the id of the thread. threads->tid() is a quick way
159 to get current thread id if you don't have your thread handy.
161 =item threads->yield();
163 This will tell the OS to let this thread yield CPU time to other threads.
164 However this is highly depending on the underlying thread implementation.
166 You may do C<use threads qw(yield)> then use just a bare C<yield> in your
169 =item threads->list();
171 This will return a list of all non joined, non detached threads.
175 C<async> creates a thread to execute the block immediately following
176 it. This block is treated as an anonymous sub, and so must have a
177 semi-colon after the closing brace. Like C<threads->new>, C<async>
178 returns a thread object.
186 =item A thread exited while %d other threads were still running
188 A thread (not necessarily the main thread) exited while there were
189 still other threads running. Usually it's a good idea to first collect
190 the return values of the created threads by joining them, and only then
191 exit from then main thread.
197 The current implmentation of threads has been an attempt to get
198 a correct threading system working that could be built on,
199 and optimized, in newer versions of perl.
201 Current the overhead of creating a thread is rather large,
202 also the cost of returning values can be large. These are areas
203 were there most likely will be work done to optimize what data
204 that needs to be cloned.
208 =item Parent-Child threads.
210 On some platforms it might not be possible to destroy "parent"
211 threads while there are still existing child "threads".
213 This will be possibly be fixed in later versions of perl.
217 The tid is a 32 bit integer, it can potentially overflow.
218 This might be fixed in a later version of perl.
220 =item Returning objects
222 When you return an object the entire stash that the object is blessed
223 as well. This will lead to a large memory usage.
224 The ideal situation would be to detect the original stash if it existed.
226 =item PERL_OLD_SIGNALS are not threadsafe, will not be.
230 =head1 AUTHOR and COPYRIGHT
232 Arthur Bergman E<lt>arthur at contiller.seE<gt>
234 threads is released under the same license as Perl.
238 Richard Soderberg E<lt>rs at crystalflame.netE<gt>
239 Helping me out tons, trying to find reasons for races and other weird bugs!
241 Simon Cozens E<lt>simon at brecon.co.ukE<gt>
242 Being there to answer zillions of annoying questions
244 Rocco Caputo E<lt>troc at netrus.netE<gt>
246 Vipul Ved Prakash E<lt>mail at vipul.netE<gt>
247 Helping with debugging.
249 please join perl-ithreads@perl.org for more information
253 L<perl>, L<threads::shared>, L<perlcall>, L<perlembed>, L<perlguts>