Re: [Vala] Threads and closures problem

[JM <interflug1 gmx net>]

Hi Łukas
Thanks for your reply! This somehow does not work as soon as I add
another thread. 

class HHH : Object {
        private ThreadFunc f;
        public void run() {
                string test = "test";
                try {
                        f = ()=> { print("in thread : %s \n", test); };
                        Thread.create(f, false);
                }
                catch(GLib.ThreadError e) {
                        print("%s", e.message);
                }
        }
        
        public static MainLoop loop;
        
        public static int main() {
                loop = new MainLoop(null, false);
                var h = new HHH();
                h.run();
                h.run(); // Another thread
                loop.run();
                return 0;
        }
}

// valac --thread hhh.vala

I get:

$./hhh
in thread : test 
in thread : (null) 

Ideas?
Regards,
Jörn

PS: Sorry for double post, but I forgot the list

Am Donnerstag, den 14.01.2010, 00:38 +0100 schrieb Łukasz Pankowski:
> JM <interflug1 gmx net> writes:
>
> > Hi all
> > I just played around with closures as thread functions. I'm not sure if
> > this example is supposed to work, but at least it compiles.
> >
> >
> > class HHH : Object {
> >     public void run() {
> >             string test = "test";
> >             try {
> >                     Thread.create( ()=> { print("in thread : %s \n", test); }, false);
>
> Hi
>
> if you look into a hhh.c generated with
>
> valac -C --thread hhh.vala
>
> you can see that the clause data is destroyed at the end of HHH.run
> (hhh_run in C) as the closure function is no longer referenced when
> exiting HHH.run, you have to assign the closure to a variable to keep
> it alive, for example
>
> class HHH : Object {
>       ThreadFunc f;
>       public void run() {
>               string test = "test";
>               try {
>                   f = ()=> { Thread.usleep(1000); print("in thread : %s \n", test); };
>                   Thread.create(f, false);
>
> it gives a compilation warning but works (I needed to add usleep to observe your problem)
>
> $ valac --thread --pkg posix temp.vala
> hhh.vala.c: In function ‘hhh_run’:
> hhh.vala.c:111: warning: assignment from incompatible pointer type
>
> > Anybody knows how this should be handled?
> > Regards
> > Jörn