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