Re: gdk_threads_enter() hangs

["Frank W. Miller" <fwmiller cornfed com>]

Thanks for the reply.

I am initializing the thread system just as you outlined.  My code is 
basically identical.  I will try taking out the other calls that are 
made by callbacks.  I was unaware of the need to handle the callbacks 
this way...


FM



Todd Fisher wrote:

> Hi Frank,
>
>    this is most likely because you are either:
>
> a. not initializing the threading system correctly.
> b. calling gdk_threads_enter within the main thread.
>
> for example in main you should make sure you're initalizing gtk+ 
> similar to the following:
>
> int main( int argc, char **argv )
> {
>  /* thread init */
>  g_thread_init( NULL );
>  gdk_threads_init();
>  gtk_init( &argc, &argv );
>
> ...
>
>  gdk_threads_enter();
>  gtk_main();
>  gdk_threads_leave();
>  return 0;
> }
>
> to satisfy condition b make sure you are not calling 
> gdk_threads_enter/leave within any callbacks
>
> main(){
> ...
> g_signal_connect( obj, "clicked", func, NULL );
> ...
> }
> void tfunc( gpointer null )
> {
>   gdk_threads_enter();
> /* update some graphical indicator */
>   gdk_threads_leave();
> }
> void func( GtkWidget *widget, gpointer null )
> {
>    GThread *tid;
>    /* gdk_threads_enter(); ERROR this would cause a dead lock such as 
> the one you describe because
>      main thread already holds the lock */
>    tid = g_thread_create( tfunc, NULL, FALSE, NULL );
> }
> for a more complete example: 
> severna.homeip.net/source/examples/simple.tar.gz
>
> hope this helps,
>
> -todd
>
> Frank W. Miller wrote:
>
> > Greetings,
> >
> > I'm having some strange behaviour.  I am writing a threaded Gnome app 
> > and it seems to be hanging when I call gdk_threads_enter().  Here's 
> > the code snippet where it hangs up:
> >
> > >                                                                                
> > >  
> > > printf("gdk_threads_enter()\n");
> > >                 gdk_threads_enter();
> > > printf("gdk_threads_enter() returned\n");
> > >                                                                                
> > >  
> >
> >
> >
> >
> > The output is (as you might guess):
> >
> > > gdk_threads_enter()
> >
> >
> >
> >
> > The second printf is never executed.  I've been over all my various 
> > gdk_threads_enter()/gdk_threads_leave() pairs to make sure I'm not 
> > locking GDK and then not unlocking it.  It seems to me to be fine.  
> > All the protected areas are very short, i.e. 1 or 2 lines of code, 
> > and the protected code is all just calls to gtk stuff.  I'm not doing 
> > any I/O inside of a protected area.  Any thoughts on this?
> >
> >
> > Thanks in advance,
> > FM
> >
> >
> >
> >
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