Wx::Thread(3) User Contributed Perl Documentation Wx::Thread(3)

NAME
       Thread - using wxPerl with threads

SYNOPSIS
         # the order of these use()s is important
         use threads;
         use threads::shared;
         use Wx;

         my $DONEEVENT : shared = Wx::NewEventType;

         my $worker = threads->create( \&work );

         # create frames, etc
         my $frame = Wx::Frame->new( ... );
         EVTCOMMAND( $frame, -1, $DONEEVENT, \&done );
         $app->MainLoop;

         sub done {
             my( $frame, $event ) = @;

             print $event->GetData;
         }

         sub work {
             # ... do stuff, create a shared $result value

             my $threvent = new Wx::PlThreadEvent( -1, $DONEEVENT, $result );
             Wx::PostEvent( $frame, $threvent );
         }

         # event handler
         sub OnCreateThread {
             # @ = () is necessary to avoid "Scalars leaked"
             my( $self, $event ) = @; @ = ();

             threads->create( ... );
         }

DESCRIPTION
       Threaded GUI application are somewhat different from non-GUI threaded
       applications in that the main thread (which runs the GUI) must never
       block.  Also, in wxWidgets, no thread other than the main thread can
       manipulate GUI objects.  This leads to a hybrid model where worker
       threads must send events to the main thread in order to change the GUI
       state or signal their termination.

       OOrrddeerr ooff mmoodduullee llooaaddiinngg

       It's necessary for "use Wx" to happen after .

       SSeennddiinngg eevveennttss ffrroomm wwoorrkkeerr tthhrreeaaddss

       "Wx::PlThreadEvent" can be used to communicate between worker and GUI
       threads.  The event can carry a shared value between threads.

         my $DONEEVENT : shared = Wx::NewEventType;

         sub work {
             # ... do some stuff
             my $progress = new Wx::PlThreadEvent( -1, $DONEEVENT, $progress );
             Wx::PostEvent( $frame, $progress );

             # ... do stuff, create a shared $result value
             my $end = new Wx::PlThreadEvent( -1, $DONEEVENT, $result );
             Wx::PostEvent( $frame, $end );
         }

       The target of the event can be any "Wx::EvtHandler"

       RReecceeiivviinngg eevveennttss ffrroomm wwoorrkkeerr tthhrreeaaddss

       "Wx::PlThreadEvent" is a command event and can be handled as such.  The
       "->GetData" method can be used to retrieve the shared data contained
       inside the event.

         my $DONEEVENT : shared = Wx::NewEventType;

         EVTCOMMAND( $frame, -1, $DONEEVENT, \&done );

         sub done {
             my( $frame, $event ) = @;

             print $event->GetData;
         }

       CCrreeaattiinngg nneeww tthhrreeaaddss

       Creating new threads from event handlers works without problems except
       from a little snag.  In order not to trigger a bug in the Perl
       interpreter, all event handler that directly or indirectly cause a
       thread creation must clean @ before starting the thread.

       For example:

         sub OnCreateThread {
             my( $self, $event ) = @; @ = ();

             threads->create( ... );
         }

       failure to do that will cause "scalars leaked" warnings from the Perl
       interpreter.



perl v5.8.8                       2007-03-16                     Wx::Thread(3)