Re: Dialog boxes in seperate thread

[jcupitt gmail com]

2008/4/30 David Conley (FRD) <dconley frd co uk>:
> Are modal dialog boxes possible in threads? I have this call in a thread
>  seperate to the main gtk thread:
>
>  gtk_dialog_run(GTK_DIALOG(errorDialog));
>
>  and obviously that locks that thread while the main thread continues but
>  nothing updates the display in the blocked thread and the app becomes
>  unresponsive.

GTK is happiest if you keep all gtk_* calls in the main thread, and if
the main thread does (almost) nothing but run the gtk event loop.

If you need to start a thread to do a long running task, don't call
gtk stuff from the thread, instead send a message to the main thread
and ask it to make the calls on the thread's behalf. This is easy to
do with g_idle_add(), which you can call safely from a worker thread.

Something like:

on_button_click( ..
{
  if (!app->bg_job)
    app->bg_job = g_thread_create( background_job ..
}

background_job ( ..
{
  for (int i = 0; i < 100; i++) {
    char *str = g_strdup_printf ("... still working! %d", i);
    g_idle_add (process_message, str);
    sleep (1)
  }
}

process_message (.. char *str)
{
  gtk_label_set (app->status, str);
  g_free (str);
}

John