Re: GTK & threads

[Marshall Lake <mlake mlake net>]

Just to let everyone know ...

I discovered that I was having an issue with my socket logic which was the 
main cause of my problem outlined below.  Once I resolved that issue and 
incorporated g_idle_add() along with GCond & GMutex into my code 
everything is working.



> (When you reply, please add CC to devel mailing list, so other peoples 
> know it's progress and may help you more).
>
> --- mlake mlake net wrote:
>
> From: Marshall Lake <mlake mlake net>
> To: Ardhan Madras <ajhwb knac com>
> Subject: Re: GTK & threads
> Date: Wed, 8 Jul 2009 12:21:34 -0400 (EDT)
>
>
> Thanks for your feedback.  I think what you say is likely my problem.
>
>
>
> On Wed, 8 Jul 2009, Ardhan Madras wrote:
>
> > Hi,
> >
> > You should be aware when call GTK+ function in another thread, if you 
> > do this from another thread, GTK+ is likely not send commands to the X 
> > server. When you run a dialog in the main thread, main loop is blocked, 
> > so the dialog's window remain displayed until a response was given (eg. 
> > button was clicked). But in you code, you run the dialog outside the 
> > main loop (main thread) the main loop of course is not blocked, and it 
> > fails to show the dialog. See 
> > http://library.gnome.org/devel/gtk-faq/stable/x499.html on howto send 
> > GTK+ funcs to the main loop. Another way is to provide mechanism so you 
> > can run the dialog from the main thread by using such as condition 
> > variable (GCond).
> >
> > -- ajhwb
> >
> > --- mlake mlake net wrote:
> >
> > From: Marshall Lake <mlake mlake net>
> > To: gtk-app-devel-list gnome org
> > Subject: GTK & threads
> > Date: Wed, 8 Jul 2009 09:38:30 -0400 (EDT)
> >
> >
> > I posted this on gtk-list but in the hope of catching a wider audience ...
> >
> > I'm developing a program(s) which runs in the client/server environment.
> > I'm using GTK, sockets, and threads.  (GTK and threads only on the client
> > side.)  I don't have very much experience using threads and this is the
> > first time I've tried to call GTK functions within a thread, and I'm
> > having problems.  I've tried different ways of approaching the problem but
> > can't seem to get anywhere.  I suspect there's something I don't
> > understand about thread processing or I'm under some misconception.
> > Maybe someone can help me?  Any help is much appreciated.
> >
> > I get the following errors when trying to run the code below (the errors
> > show up when the program calls gtk_dialog_run() in the thread
> > (Wait4Challenge()):
> >
> > src/xcb_io.c:242: process_responses: Assertion `(((long) (dpy->last_request_read) - (long) (dpy->request)) <= 
> > 0)' failed.
> > Fatal IO error 0 (Success) on X server :0.0.
> >
> >
> > void *
> > Wait4Challenge () {
> >       int wsock, x, port = 0, listensock, connected;
> >       char buffer[5000], *msg[5], challenger[50];
> >
> >       listensock = -1;
> >       for (x = 0; x < 5; x++)
> >           msg[x] = NULL;
> >
> >       wsock = get_connection (SOCK_STREAM, port, &listensock);
> >
> >       connected = 1;
> >       while (connected) {
> >           GtkWidget *dialog;
> >           int response;
> >
> >           if (sock_gets (wsock, &buffer[0], sizeof (buffer)) < 0) {
> >               msg[0] = "There is a problem with the server.\n\n";
> >               outMessage (msg);
> >               connected = 0;
> >           }
> >
> >           if (buffer[0] == 'R')
> >               connected = 0;
> >
> >           if (buffer[0] != 'C')
> >               continue;
> >
> >           strcpy (&challenger[0], &buffer[1]);
> >
> >           gdk_threads_enter ();
> >
> >           dialog = gtk_message_dialog_new (GTK_WINDOW (mainwin), GTK_DIALOG_DESTROY_WITH_PARENT, 
> > GTK_MESSAGE_QUESTION,
> >                               GTK_BUTTONS_YES_NO, "%s has challenged you to a game.  Do you wish to play?", 
> > challenger);
> >           gtk_window_set_title (GTK_WINDOW (dialog), "Play Challenger?");
> >           response = gtk_dialog_run (GTK_DIALOG (dialog));
> >           gtk_widget_destroy (dialog);
> >
> >           gdk_flush();
> >           gdk_threads_leave ();
> >
> >           if (response == GTK_RESPONSE_YES) {
> >               sock_puts (wsock, "OK\n");
> >               connected = 0;
> >           }
> >           else {
> >               sock_puts (wsock, "NO\n");
> >               for (x = 0; x < 5; x++)
> >                   msg[x] = NULL;
> >               continue;
> >           }
> >       }
> >
> >       shutdown (wsock, SHUT_RDWR);
> >       close (wsock);
> >       return (NULL);
> > }
> >
> > int
> > main (int argc, char *argv[]) {
> >       g_thread_init (NULL);
> >       gdk_threads_init ();
> >
> >       gtk_init (&argc, &argv);
> >
> >       mainwin = gtk_window_new (GTK_WINDOW_TOPLEVEL);
> >       gtk_widget_set_usize (mainwin, WINSIZEX, WINSIZEY);
> >       gtk_widget_realize (mainwin);
> >
> >       gtk_widget_add_events (mainwin, GDK_BUTTON_PRESS_MASK);
> >       gtk_signal_connect (GTK_OBJECT (mainwin), "delete_event", GTK_SIGNAL_FUNC (delete_event), 0);
> >
> >       gtk_widget_show_all (mainwin);
> >
> >       if (!g_thread_create (Wait4Challenge, NULL, FALSE, NULL))
> >           syslog (LOG_INFO, "error trying to create new thread");
> >
> >       gdk_threads_enter ();
> >
> >       gtk_main ();
> >
> >       gdk_flush();
> >       gdk_threads_leave ();
> >
> >       return 0;
> > }
> >
> > --
> > Marshall Lake -- mlake mlake net -- http://mlake.net


--
Marshall Lake -- mlake mlake net -- http://mlake.net