package threads;
-use 5.007_003;
+use 5.008;
+
use strict;
use warnings;
-use Config;
-
-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.)
+our $VERSION = '1.24_01';
+my $XS_VERSION = $VERSION;
+$VERSION = eval $VERSION;
-Having threads support requires all of Perl and all of the 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
+BEGIN {
+ # Verify this Perl supports threads
+ use Config;
+ if (! $Config{useithreads}) {
+ die("This Perl not built to support threads\n");
}
-}
-use overload
- '==' => \&equal,
- 'fallback' => 1;
-
-#use threads::Shared;
-
-BEGIN {
- warn "Warning, threads::shared has already been loaded. ".
- "To enable shared variables for these modules 'use threads' ".
- "must be called before any of those modules are loaded\n"
- if($threads::shared::threads_shared);
+ # Declare that we have been loaded
+ $threads::threads = 1;
+
+ # Complain if 'threads' is loaded after 'threads::shared'
+ if ($threads::shared::threads_shared) {
+ warn <<'_MSG_';
+Warning, threads::shared has already been loaded. To
+enable shared variables, 'use threads' must be called
+before threads::shared or any module that uses it.
+_MSG_
+ }
}
-require Exporter;
-require DynaLoader;
+# Load the XS code
+require XSLoader;
+XSLoader::load('threads', $XS_VERSION);
-our @ISA = qw(Exporter DynaLoader);
-our %EXPORT_TAGS = ( all => [qw()]);
+### Export ###
-our @EXPORT_OK = ( @{ $EXPORT_TAGS{'all'} } );
+sub import
+{
+ my $class = shift; # Not used
-our @EXPORT = qw(
-
-);
-our $VERSION = '0.99';
+ # Exported subroutines
+ my @EXPORT = qw(async);
+ # Handle args
+ while (my $sym = shift) {
+ if ($sym =~ /all/) {
+ push(@EXPORT, qw(yield));
-sub equal {
- return 1 if($_[0]->tid() == $_[1]->tid());
- return 0;
+ } else {
+ push(@EXPORT, $sym);
+ }
+ }
+
+ # Export subroutine names
+ my $caller = caller();
+ foreach my $sym (@EXPORT) {
+ no strict 'refs';
+ *{$caller.'::'.$sym} = \&{$sym};
+ }
}
-$threads::threads = 1;
-bootstrap threads $VERSION;
+### Methods, etc. ###
-# why document 'new' then use 'create' in the tests!
-*create = \&new;
+# 'new' is an alias for 'create'
+*new = \&create;
+
+# 'async' is a function alias for the 'threads->create()' method
+sub async (&;@)
+{
+ unshift(@_, 'threads');
+ # Use "goto" trick to avoid pad problems from 5.8.1 (fixed in 5.8.2)
+ goto &create;
+}
-# Preloaded methods go here.
+# Thread object equality checking
+use overload (
+ '==' => \&equal,
+ '!=' => sub { ! equal(@_) },
+ 'fallback' => 1
+);
1;
+
__END__
=head1 NAME
-threads - Perl extension allowing use of interpreter based threads from perl
+threads - Perl interpreter-based threads
+
+=head1 VERSION
+
+This document describes threads version 1.24
=head1 SYNOPSIS
-use threads;
+ use threads ('yield');
-sub start_thread {
- print "Thread started\n";
-}
+ sub start_thread {
+ my @args = @_;
+ print "Thread started: @args\n";
+ }
+ my $thread = threads->create('start_thread', 'argument');
+ $thread->join();
-my $thread = threads->create("start_thread","argument");
+ threads->create(sub { print("I am a thread\n"); })->join();
-$thread->create(sub { print "I am a thread"},"argument");
+ my $thread3 = async { foreach (@files) { ... } };
+ $thread3->join();
-$thread->join();
+ # Invoke thread in list context so it can return a list
+ my ($thr) = threads->create(sub { return (qw/a b c/); });
+ my @results = $thr->join();
-$thread->detach();
+ $thread->detach();
-$thread = threads->self();
+ $thread = threads->self();
+ $thread = threads->object($tid);
-threads->tid();
-threads->self->tid();
+ $tid = threads->tid();
+ $tid = threads->self->tid();
+ $tid = $thread->tid();
-$thread->tid();
+ threads->yield();
+ yield();
-threads->yield();
+ my @threads = threads->list();
+ my $thread_count = threads->list();
-threads->list();
+ if ($thr1 == $thr2) {
+ ...
+ }
=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.
+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.
variables are per default thread local. To use shared variables one
must use threads::shared.
-It is also important to note that you preferably enable threads by
-doing C<use threads> as early as possible and that it is not possible
-to enable threading inside an eval ""; In particular, if you are
-intending to share variables with threads::shared, you must
-C<use threads> before you C<use threads::shared> and threads will emit
-a warning if you do it the other way around.
+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 $thread = threads->create(function, LIST)
+=item $thr = threads->create(FUNCTION, ARGS)
+
+This will create a new thread that will begin execution with the specified
+entry point function, and give it the I<ARGS> list as parameters. It will
+return the corresponding threads object, or C<undef> if thread creation failed.
+
+I<FUNCTION> may either be the name of a function, an anonymous subroutine, or
+a code ref.
+
+ my $thr = threads->create('func_name', ...);
+ # or
+ my $thr = threads->create(sub { ... }, ...);
+ # or
+ my $thr = threads->create(\&func, ...);
+
+The thread may be created in I<list> context, or I<scalar> context as follows:
+
+ # Create thread in list context
+ my ($thr) = threads->create(...);
+
+ # Create thread in scalar context
+ my $thr = threads->create(...);
+
+This has consequences for the C<-E<gt>join()> method describe below.
+
+Although a thread may be created in I<void> context, to do so you must
+I<chain> either the C<-E<gt>join()> or C<-E<gt>detach()> method to the
+C<-E<gt>create()> call:
+
+ threads->create(...)->join();
+
+The C<-E<gt>new()> method is an alias for C<-E<gt>create()>.
+
+=item $thr->join()
+
+This will wait for the corresponding thread to complete its execution. When
+the thread finishes, C<-E<gt>join()> will return the return value(s) of the
+entry point function.
+
+The context (void, scalar or list) of the thread creation is also the
+context for C<-E<gt>join()>. This means that if you intend to return an array
+from a thread, you must use C<my ($thr) = threads->create(...)>, and that
+if you intend to return a scalar, you must use C<my $thr = ...>:
+
+ # Create thread in list context
+ my ($thr1) = threads->create(sub {
+ my @results = qw(a b c);
+ return (@results);
+ };
+ # Retrieve list results from thread
+ my @res1 = $thr1->join();
+
+ # Create thread in scalar context
+ my $thr2 = threads->create(sub {
+ my $result = 42;
+ return ($result);
+ };
+ # Retrieve scalar result from thread
+ my $res2 = $thr2->join();
+
+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 L<exit()|perlfunc/"exit EXPR">, or in the case
+of the main thread, reaches the end of the main program file.)
+
+Calling C<-E<gt>join()> or C<-E<gt>detach()> on an already joined thread will
+cause an error to be thrown.
-This will create a new thread with the entry point function and give
-it LIST as parameters. It will return the corresponding threads
-object.
+=item $thr->detach()
-=item $thread->join
+Makes the thread unjoinable, and causes any eventual return value to be
+discarded.
-This will wait for the corresponding thread to join. When it finishes
-join will return the return values of the entry point function. If a
-thread has been detached, an error will be thrown..
+Calling C<-E<gt>join()> or C<-E<gt>detach()> on an already detached thread
+will cause an error to be thrown.
-=item $thread->detach
+=item threads->detach()
-Will throw away the return value from the thread and make it
-non-joinable.
+Class method that allows a thread to detach itself.
-=item threads->self
+=item threads->self()
-This will return the object for the current thread.
+Class method that allows a thread to obtain its own I<threads> object.
-=item $thread->tid
+=item $thr->tid()
-This will return the id of the thread. threads->tid() is a quick way
-to get current thread id if you don't have your thread handy.
+Returns the ID of the thread. Thread IDs are unique integers with the main
+thread in a program being 0, and incrementing by 1 for every thread created.
-=item threads->yield();
+=item threads->tid()
-This will tell the OS to let this thread yield CPU time to other threads.
-However this is highly depending on the underlying thread implmentation.
+Class method that allows a thread to obtain its own ID.
-=item threads->list();
+=item threads->object($tid)
-This will return a list of all non joined, non detached threads.
+This will return the I<threads> object for the I<active> thread associated
+with the specified thread ID. Returns C<undef> if there is no thread
+associated with the TID, if the thread is joined or detached, if no TID is
+specified or if the specified TID is undef.
+
+=item threads->yield()
+
+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.
+
+You may do C<use threads qw(yield)>, and then just use C<yield()> in your
+code.
+
+=item threads->list()
+
+In a list context, returns a list of all non-joined, non-detached I<threads>
+objects. In a scalar context, returns a count of the same.
+
+=item $thr1->equal($thr2)
+
+Tests if two threads objects are the same thread or not. This is overloaded
+to the more natural forms:
+
+ if ($thr1 == $thr2) {
+ print("Threads are the same\n");
+ }
+ # or
+ if ($thr1 != $thr2) {
+ print("Threads differ\n");
+ }
+
+(Thread comparison is based on thread IDs.)
+
+=item async BLOCK;
+
+C<async> creates a thread to execute the block immediately following
+it. This block is treated as an anonymous subroutine, and so must have a
+semi-colon after the closing brace. Like C<threads->create()>, C<async>
+returns a I<threads> object.
+
+=item $thr->_handle()
+
+This I<private> method returns the memory location of the internal thread
+structure associated with a threads object. For Win32, this is a pointer to
+the C<HANDLE> value returned by C<CreateThread> (i.e., C<HANDLE *>); for other
+platforms, it is a pointer to the C<pthread_t> structure used in the
+C<pthread_create> call (i.e., C<pthread_t *>.
+
+This method is of no use for general Perl threads programming. Its intent is
+to provide other (XS-based) thread modules with the capability to access, and
+possibly manipulate, the underlying thread structure associated with a Perl
+thread.
+
+=item threads->_handle()
+
+Class method that allows a thread to obtain its own I<handle>.
=back
=over 4
-=item Cleanup skipped %d active threads
+=item A thread exited while # other threads were still running
-The main thread exited while there were still other threads running.
-This is not a good sign: you should either explicitly join the threads,
-or somehow be certain that all the non-main threads have finished.
+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.
=back
-=head1 BUGS / TODO
+=head1 ERRORS
-The current implmentation 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.
+=over 4
-Current 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.
+=item This Perl not built to support threads
-=over
+The particular copy of Perl that you're trying to use was not built using the
+C<useithreads> configuration option.
-=item Parent-Child threads.
+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
+L<threads> module (i.e., threaded and non-threaded Perls are binary
+incompatible.)
-On some platforms it might not be possible to destroy "parent"
-threads while there are still existing child "threads".
+=back
+
+=head1 BUGS
-This will be possibly be fixed in later versions of perl.
+=over
-=item tid is I32
+=item Parent-child threads
-The tid is a 32 bit integer, it can potentially overflow.
-This might be fixed in a later version of perl.
+On some platforms, it might not be possible to destroy I<parent> threads while
+there are still existing I<child> threads.
-=item Returning objects
+=item Creating threads inside BEGIN blocks
-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.
+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.
+
+=item Returning closures from threads
+
+Returning a closure from a thread does not work, usually crashing Perl in the
+process.
+
+=item Perl Bugs and the CPAN Version of L<threads>
+
+Support for threads extents beyond the code in this module (i.e.,
+F<threads.pm> and F<threads.xs>), and into the Perl iterpreter itself. Older
+versions of Perl contain bugs that may manifest themselves despite using the
+latest version of L<threads> from CPAN. There is no workaround for this other
+than upgrading to the lastest version of Perl.
+
+(Before you consider posting a bug report, please consult, and possibly post a
+message to the discussion forum to see if what you've encountered is a known
+problem.)
+
=back
-=head1 AUTHOR and COPYRIGHT
+=head1 REQUIREMENTS
-Arthur Bergman E<lt>arthur at contiller.seE<gt>
+Perl 5.8.0 or later
-threads is released under the same license as Perl.
+=head1 SEE ALSO
-Thanks to
+L<threads> Discussion Forum on CPAN:
+L<http://www.cpanforum.com/dist/threads>
-Richard Soderberg E<lt>rs at crystalflame.netE<gt>
-Helping me out tons, trying to find reasons for races and other weird bugs!
+Annotated POD for L<threads>:
+L<http://annocpan.org/~JDHEDDEN/threads-1.24/shared.pm>
-Simon Cozens E<lt>simon at brecon.co.ukE<gt>
-Being there to answer zillions of annoying questions
+L<threads::shared>, L<perlthrtut>
-Rocco Caputo E<lt>troc at netrus.netE<gt>
+L<http://www.perl.com/pub/a/2002/06/11/threads.html> and
+L<http://www.perl.com/pub/a/2002/09/04/threads.html>
-Vipul Ved Prakash E<lt>mail at vipul.netE<gt>
-Helping with debugging.
+Perl threads mailing list:
+L<http://lists.cpan.org/showlist.cgi?name=iThreads>
-please join perl-ithreads@perl.org for more information
+=head1 AUTHOR
+Artur Bergman E<lt>sky AT crucially DOT netE<gt>
+threads is released under the same license as Perl.
+CPAN version produced by Jerry D. Hedden <jdhedden AT cpan DOT org>
-=head1 SEE ALSO
+=head1 ACKNOWLEDGEMENTS
+
+Richard Soderberg E<lt>perl AT crystalflame DOT netE<gt> -
+Helping me out tons, trying to find reasons for races and other weird bugs!
+
+Simon Cozens E<lt>simon AT brecon DOT co DOT ukE<gt> -
+Being there to answer zillions of annoying questions
+
+Rocco Caputo E<lt>troc AT netrus DOT netE<gt>
-L<perl>, L<threads::shared>, L<perlcall>, L<perlembed>, L<perlguts>
+Vipul Ved Prakash E<lt>mail AT vipul DOT netE<gt> -
+Helping with debugging
=cut
projects / p5sagit/p5-mst-13.2.git / blobdiff