Re: [Vala] Threads and closures problem

[JM <interflug1 gmx net>]

Hi all
Looks like closures and threads are incompatible right now.
This is the ccode generated from vala.
VALA:
Thread.create( ()=> { Thread.usleep(1000); print("in thread : %s \n",
test); }, false);

CCODE:
g_thread_create (__lambda0__gthread_func, _data1_, FALSE,
&_inner_error_);

CCODE (with owned ThreadFunc in vapi):
g_thread_create (__lambda0__gthread_func, block1_data_ref (_data1_),
block1_data_unref, FALSE, &_inner_error_);

As you can see, the second ccode produces one too many args for the
g_thread_create function, while for the first case the '_data1_' struct
is immediately freed as soon as the calling function is finished.

I don't really know how and if this can be fixed.
I thought this would be an easy option to hand over some parameters to a
thread function. 
Are there other good options to put parameters to threads without
accessing class variables + mutex locking?
Regards
Jörn



Am Donnerstag, den 14.01.2010, 12:40 +0100 schrieb JM:
> Hello all
> Thanks Łukasz for your reply! 
> That explains the behavior. But then, shouldn't a thread also own the
> thread function or will that lead to other issues?
>
> Should the vapi binding be:
> public static weak Thread create (owned ThreadFunc func, bool joinable)
> throws ThreadError;
>
> instdead of:
> public static weak Thread create (ThreadFunc func, bool joinable) throws
> ThreadError;
>
> ???
>
> Then the closure handled by the thread will maybe not be freed too
> early.
>
> I really hope to clear all this because that looks like the only way to
> pass some parameters to a threadfunction.
> Regards, 
> Jörn
>
>
> Am Donnerstag, den 14.01.2010, 11:06 +0100 schrieb Łukasz Pankowski:
> > JM <interflug1 gmx net> writes:
> >
> > > If I do the same thing with an Idle, the behavior is significantly
> > > different, as the block data is not destroyed as soon as the run()
> > > function is left. Why is that?
> > >
> > > Well working example:
> > >
> > > class HHH : Object {
> > >   public void run() {
> > >           string test = "test";
> > >           Idle.add(() => { print("in idle : %s \n", test); return false;});
> >
> > if you look into glib-2.0.vapi Idle.add is declared as:
> >
> >             public static uint add (owned SourceFunc function, [CCode (pos = 0.1)] int priority = 
> > Priority.DEFAULT_IDLE);
> >
> > so the add() is declared to own the function past to it, so the closure data will be kept alive
> >
> > >   }
> > >
> > >   public static MainLoop loop;
> > >
> > >   public static int main() {
> > >           loop = new MainLoop(null, false);
> > >           var h = new HHH();
> > >           h.run();
> > >           h.run();
> > >           h.run();
> > >           h.run();
> > >           loop.run();
> > >           return 0;
> > >   }
> > > }
> > >
> > > // valac closuretest.vala
>
>
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