-
-
package threads;
-use 5.7.2;
+use 5.008;
use strict;
use warnings;
+use Config;
-use overload
- '==' => \&equals,
- 'fallback' => 1;
+BEGIN {
+ unless ($Config{useithreads}) {
+ my @caller = caller(2);
+ die <<EOF;
+$caller[1] line $caller[2]:
+
+This Perl hasn't been configured and built properly for the threads
+module to work. (The 'useithreads' configuration option hasn't been used.)
+Having threads support requires all of Perl and all of the XS modules in
+the Perl installation to be rebuilt, it is not just a question of adding
+the threads module. (In other words, threaded and non-threaded Perls
+are binary incompatible.)
+
+If you want to the use the threads module, please contact the people
+who built your Perl.
+
+Cannot continue, aborting.
+EOF
+ }
+}
+
+use overload
+ '==' => \&equal,
+ 'fallback' => 1;
#use threads::Shared;
+BEGIN {
+ warn "Warning, threads::shared has already been loaded. ".
+ "To enable shared variables for these modules 'use threads' ".
+ "must be called before any of those modules are loaded\n"
+ if($threads::shared::threads_shared);
+}
+
require Exporter;
require DynaLoader;
-use Devel::Peek;
-
-
our @ISA = qw(Exporter DynaLoader);
-our %EXPORT_TAGS = ( all => [qw()]);
+our %EXPORT_TAGS = ( all => [qw(yield)]);
our @EXPORT_OK = ( @{ $EXPORT_TAGS{'all'} } );
our @EXPORT = qw(
-
+async
);
-our $VERSION = '0.05';
-
-sub new {
- my $class = shift;
- print (Dump($_[0]));
- return $class->create(@_);
-}
+our $VERSION = '0.99';
-sub equals {
+sub equal {
return 1 if($_[0]->tid() == $_[1]->tid());
return 0;
}
-$Config::threads = 1;
+sub async (&;@) {
+ my $cref = shift;
+ return threads->new($cref,@_);
+}
+
+sub object {
+ return undef unless @_ > 1;
+ foreach (threads->list) {
+ return $_ if $_->tid == $_[1];
+ }
+ return undef;
+}
+
+$threads::threads = 1;
bootstrap threads $VERSION;
+# why document 'new' then use 'create' in the tests!
+*create = \&new;
# Preloaded methods go here.
=head1 SYNOPSIS
+ use threads;
-use threads;
-
-sub start_thread {
- print "Thread started\n";
-}
+ sub start_thread {
+ print "Thread started\n";
+ }
+ my $thread = threads->create("start_thread","argument");
+ my $thread2 = $thread->create(sub { print "I am a thread"},"argument");
+ my $thread3 = async { foreach (@files) { ... } };
-my $thread = threads->new("start_thread","argument");
+ $thread->join();
+ $thread->detach();
-$thread->new(sub { print "I am a thread"},"argument");
+ $thread = threads->self();
+ $thread = threads->object( $tid );
-$thread->join();
+ $thread->tid();
+ threads->tid();
+ threads->self->tid();
-$thread->detach();
+ threads->yield();
-$thread = threads->self();
+ threads->list();
-thread->tid();
+=head1 DESCRIPTION
+Perl 5.6 introduced something called interpreter threads. Interpreter
+threads are different from "5005threads" (the thread model of Perl
+5.005) by creating a new perl interpreter per thread and not sharing
+any data or state between threads by default.
+Prior to perl 5.8 this has only been available to people embedding
+perl and for emulating fork() on windows.
-=head1 DESCRIPTION
+The threads API is loosely based on the old Thread.pm API. It is very
+important to note that variables are not shared between threads, all
+variables are per default thread local. To use shared variables one
+must use threads::shared.
-Perl 5.6 has something called interpreter threads, interpreter threads are built on MULTIPLICITY and allows for several different perl interpreters to run in different threads. This has been used in win32 perl to fake forks, it has also been available to people embedding perl.
+It is also important to note that you must enable threads by doing
+C<use threads> as early as possible in the script itself and that it
+is not possible to enable threading inside an C<eval "">, C<do>,
+C<require>, or C<use>. In particular, if you are intending to share
+variables with threads::shared, you must C<use threads> before you
+C<use threads::shared> and C<threads> will emit a warning if you do
+it the other way around.
=over
-=item new, function, LIST
+=item $thread = threads->create(function, LIST)
-This will create a new thread with the entry point function and give it LIST as parameters.
-It will return the corresponding threads object.
+This will create a new thread with the entry point function and give
+it LIST as parameters. It will return the corresponding threads
+object. The new() method is an alias for create().
-=item $threads->join
+=item $thread->join
-This will wait for the corresponding thread to join. When it finishes join will return the return values of the root function.
-If a thread has been detached, join will return without wait.
+This will wait for the corresponding thread to join. When the thread
+finishes, join() will return the return values of the entry point
+function. If the thread has been detached, an error will be thrown.
-=item $threads->detach
+The context (scalar or list) of the thread creation is also the
+context for join(). This means that if you intend to return an array
+from a thread, you must use C<my ($thread) = threads->new(...)>, and
+that if you intend to return a scalar, you must use C<my $thread = ...>.
-Will throw away the return value from the thread and make non joinable
+If the program exits without all other threads having been either
+joined or detached, then a warning will be issued. (A program exits
+either because one of its threads explicitly calls exit(), or in the
+case of the main thread, reaches the end of the main program file.)
+
+
+=item $thread->detach
+
+Will make the thread unjoinable, and cause any eventual return value
+to be discarded.
=item threads->self
-This will return the object for the current thread.
+This will return the thread object for the current thread.
-=item $threads->tid
+=item $thread->tid
-This will return the id of the thread.
-threads->self->tid() is a quick way to get current thread id
+This will return the id of the thread. Thread IDs are integers, with
+the main thread in a program being 0. Currently Perl assigns a unique
+tid to every thread ever created in your program, assigning the first
+thread to be created a tid of 1, and increasing the tid by 1 for each
+new thread that's created.
-=back
+NB the class method C<< threads->tid() >> is a quick way to get the
+current thread id if you don't have your thread object handy.
+=item threads->object( tid )
-=head1 TODO
+This will return the thread object for the thread associated with the
+specified tid. Returns undef if there is no thread associated with the tid
+or no tid is specified or the specified tid is undef.
-=over
+=item threads->yield();
-=item Fix so the return value is returned when you join
+This is a suggestion to the OS to let this thread yield CPU time to other
+threads. What actually happens is highly dependent upon the underlying
+thread implementation.
-=item Add join_all
+You may do C<use threads qw(yield)> then use just a bare C<yield> in your
+code.
-=item Fix memory leaks!
+=item threads->list();
-=back
+This will return a list of all non joined, non detached threads.
-=head1 AUTHOR and COPYRIGHT
+=item async BLOCK;
-Artur Bergman <lt>artur at contiller.se<gt>
+C<async> creates a thread to execute the block immediately following
+it. This block is treated as an anonymous sub, and so must have a
+semi-colon after the closing brace. Like C<< threads->new >>, C<async>
+returns a thread object.
-threads is released under the same license as Perl
+=back
-Thanks to
+=head1 WARNINGS
-Richard Soderberg <lt>rs at crystalflame.net<gt>
-Helping me out tons, trying to find reasons for races and other wierd bugs!
+=over 4
-Simon Cozens <lt>simon at brecon.co.uk<gt>
-Being there to answer zillions of annoying questions
+=item A thread exited while %d other threads were still running
-Rocco Caputo <lt>troc at netrus.net<gt>
+A thread (not necessarily the main thread) exited while there were
+still other threads running. Usually it's a good idea to first collect
+the return values of the created threads by joining them, and only then
+exit from the main thread.
-Vipul Ved Prakash <lt>mail at vipul.net<gt>
-Helping with debugging.
+=back
-please join perl-ithreads@perl.org for more information
+=head1 TODO
+
+The current implementation of threads has been an attempt to get
+a correct threading system working that could be built on,
+and optimized, in newer versions of perl.
+
+Currently the overhead of creating a thread is rather large,
+also the cost of returning values can be large. These are areas
+were there most likely will be work done to optimize what data
+that needs to be cloned.
=head1 BUGS
=over
-=item creating a thread from within a thread is unsafe under win32
+=item Parent-Child threads.
+
+On some platforms it might not be possible to destroy "parent"
+threads while there are still existing child "threads".
+
+This will possibly be fixed in later versions of perl.
+
+=item tid is I32
+
+The thread id is a 32 bit integer, it can potentially overflow.
+This might be fixed in a later version of perl.
+
+=item Returning objects
+
+When you return an object the entire stash that the object is blessed
+as well. This will lead to a large memory usage. The ideal situation
+would be to detect the original stash if it existed.
+
+=item Creating threads inside BEGIN blocks
+
+Creating threads inside BEGIN blocks (or during the compilation phase
+in general) does not work. (In Windows, trying to use fork() inside
+BEGIN blocks is an equally losing proposition, since it has been
+implemented in very much the same way as threads.)
+
+=item PERL_OLD_SIGNALS are not threadsafe, will not be.
+
+If your Perl has been built with PERL_OLD_SIGNALS (one has
+to explicitly add that symbol to ccflags, see C<perl -V>),
+signal handling is not threadsafe.
=back
-=head1 SEE ALSO
+=head1 AUTHOR and COPYRIGHT
-L<perl>, L<perlcall>, L<perlembed>, L<perlguts>
+Arthur Bergman E<lt>arthur at contiller.seE<gt>
-=cut
+threads is released under the same license as Perl.
+
+Thanks to
+
+Richard Soderberg E<lt>rs at crystalflame.netE<gt>
+Helping me out tons, trying to find reasons for races and other weird bugs!
+Simon Cozens E<lt>simon at brecon.co.ukE<gt>
+Being there to answer zillions of annoying questions
+Rocco Caputo E<lt>troc at netrus.netE<gt>
+Vipul Ved Prakash E<lt>mail at vipul.netE<gt>
+Helping with debugging.
+
+please join perl-ithreads@perl.org for more information
+=head1 SEE ALSO
+
+L<threads::shared>, L<perlthrtut>,
+L<http://www.perl.com/pub/a/2002/06/11/threads.html>,
+L<perlcall>, L<perlembed>, L<perlguts>
+
+=cut
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