Re: thread problem

[Tristan Van Berkom <vantr touchtunes com>]

Bart Vandewoestyne wrote:

> The problem is simple:
>
> I have a START and a STOP button in my gtk application.  The start
> button has a callback in which a g_thread is being started.  Within that
> thread, I'm continuously downloading a stream until the user decides to
> stop by pressing the 'STOP' button.
>
> Now the problem is that i don't know how to interrupt the continously
> downloading thread by pressing the stop button.
>
> Obviously, the callback of STOP has to do something, but i don't know
> what.  Is there some way that i can make the stop button stop the other
> thread that is running (somehow the same as you would end the
> application by pressing Ctrl-C) ?
>
> Full source code with Makefile is under the src/ directory in
> mc303.ulyssis.org/downloads/mms_gui.tar.gz for those who want to
> investigate.  grep for the 'go_clicked' callback to understand what I'm
> talking about.
>
> Greetzzz,
> Bart
>
>  
you could take a number of aproaches, here are 2

1.) if you dont care about the child thread's data at the time
you press "STOP" then you could use kill(2).

2.) if you want to do things a little cleaner you could:

   in child thread {
       //loop in small itterations
       //and always check:
       g_mutex_lock(stop_mutex);
       if (stop_variable) {
           // cleanup code:          
           g_mutex_unlock(stop_mutex);
           exit(0);
       }
       g_mutex_unlock(stop_mutex);
   }

   in parent thread {
       g_mutex_lock(stop_mutex);
       stop_variable = TRUE;
       g_mutex_unlock(stop_mutex);
       g_thread_join(...);
   }


Cheers,
                                   -Tristan