From: Artur Bergman <sky@nanisky.com>
Date: Sun, 28 Oct 2001 21:02:33 +0000 (+0000)
Subject: Update documentation.
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=515f097614eaa79c1f9c40647e200dc7dc7dd619;p=p5sagit%2Fp5-mst-13.2.git

Update documentation.

p4raw-id: //depot/perl@12749
---

diff --git a/ext/threads/shared/shared.pm b/ext/threads/shared/shared.pm
index b212a41..5607186 100644
--- a/ext/threads/shared/shared.pm
+++ b/ext/threads/shared/shared.pm
@@ -27,7 +27,7 @@ require DynaLoader;
 our @ISA = qw(Exporter DynaLoader);
 
 our @EXPORT = qw(share cond_wait cond_broadcast cond_signal unlock);
-our $VERSION = '0.01';
+our $VERSION = '0.90';
 
 our %shared;
 
@@ -119,11 +119,11 @@ threads::shared - Perl extension for sharing data structures between threads
   my $bar = share([]);
   $hash{bar} = share({});
 
-  lock(\%hash);
-  unlock(\%hash);
+  lock(%hash);
+  unlock(%hash);
   cond_wait($scalar);
-  cond_broadcast(\@array);
-  cond_signal($scalar);
+  cond_broadcast(@array);
+  cond_signal(%hash);
 
 =head1 DESCRIPTION
 
@@ -131,13 +131,87 @@ This modules allows you to share() variables. These variables will
 then be shared across different threads (and pseudoforks on
 win32). They are used together with the threads module.
 
-=head2 EXPORT
+=head1 EXPORT
 
-share(), lock(), unlock(), cond_wait, cond_signal, cond_broadcast
+C<share>, C<lock>, C<unlock>, C<cond_wait>, C<cond_signal>, C<cond_broadcast>
+
+=head1 FUNCTIONS
+
+=over 4
+
+=item share VARIABLE
+
+C<share> takes a value and marks it as shared, you can share an scalar, array, hash
+scalar ref, array ref and hash ref, C<share> will return the shared value.
+
+C<share> will traverse up references exactly I<one> level.
+C<share(\$a)> is equivalent to C<share($a)>, while C<share(\\$a)> is not.
+
+=item lock VARIABLE
+
+C<lock> places a lock on a variable until the lock goes out of scope.  If
+the variable is locked by another thread, the C<lock> call will block until
+it's available. C<lock> is recursive, so multiple calls to C<lock> are
+safe--the variable will remain locked until the outermost lock on the
+variable goes out of scope or C<unlock> is called enough times to match 
+the number of calls to <lock>.
+
+If a container object, such as a hash or array, is locked, all the elements
+of that container are not locked. For example, if a thread does a C<lock
+@a>, any other thread doing a C<lock($a[12])> won't block.
+
+C<lock> will traverse up references exactly I<one> level.
+C<lock(\$a)> is equivalent to C<lock($a)>, while C<lock(\\$a)> is not.
+
+
+=item unlock VARIABLE
+
+C<unlock> takes a locked shared value and decrements the lock count.
+If the lock count is zero the variable is unlocked. It is not necessary
+to call C<unlock> but it can be usefull to reduce lock contention.
+
+C<unlock> will traverse up references exactly I<one> level.
+C<unlock(\$a)> is equivalent to C<unlock($a)>, while C<unlock(\\$a)> is not.
+
+=item cond_wait VARIABLE
+
+The C<cond_wait> function takes a B<locked> variable as a parameter,
+unlocks the variable, and blocks until another thread does a C<cond_signal>
+or C<cond_broadcast> for that same locked variable. The variable that
+C<cond_wait> blocked on is relocked after the C<cond_wait> is satisfied.
+If there are multiple threads C<cond_wait>ing on the same variable, all but
+one will reblock waiting to reaquire the lock on the variable. (So if
+you're only using C<cond_wait> for synchronization, give up the lock as
+soon as possible)
+
+It is important to note that the variable can be notified even if no
+thread C<cond_signal> or C<cond_broadcast> on the variable. It is therefore
+important to check the value of the variable and go back to waiting if the
+requirment is not fullfilled.
+
+=item cond_signal VARIABLE
+
+The C<cond_signal> function takes a B<locked> variable as a parameter and
+unblocks one thread that's C<cond_wait>ing on that variable. If more than
+one thread is blocked in a C<cond_wait> on that variable, only one (and
+which one is indeterminate) will be unblocked.
+
+If there are no threads blocked in a C<cond_wait> on the variable, the
+signal is discarded.
+
+=item cond_broadcast VARIABLE
+
+The C<cond_broadcast> function works similarly to C<cond_signal>.
+C<cond_broadcast>, though, will unblock B<all> the threads that are blocked
+in a C<cond_wait> on the locked variable, rather than only one.
 
 =head1 BUGS
 
-Not stress tested!
+C<bless> is not supported on shared references, in the current version
+C<bless> will only bless the thread local reference and the blessing
+will not propagate to the other threads, this is expected to be implmented
+in the future.
+
 Does not support splice on arrays!
 
 =head1 AUTHOR
@@ -146,8 +220,15 @@ Arthur Bergman E<lt>arthur at contiller.seE<gt>
 
 threads::shared is released under the same license as Perl
 
+Documentation borrowed from Thread.pm
+
 =head1 SEE ALSO
 
 L<perl> L<threads>
 
 =cut
+
+
+
+
+