Search code examples
signalsdaemongtk3logout

gtk3 - logout during g_application_hold()

My gtk3 application can either run within a GUI or in daemon-mode. In order to realize daemon-mode, I use g_application_hold().

So far this works great, however as soon as I logout from my session while running the application in daemon mode, my system freezes for 8 seconds, until OS kills it. Like that my clean shutdown procedure is not executed. That only happens for the daemon, not while in GUI-mode.

Currently I solved the problem by hooking the SIGHUP signal, which can be used to realize a session logout:

static void
handle_hangup_signal (int signal)
{
  MyApplication     *application = my_application_get ();
  g_application_release (G_APPLICATION (application));
}
...
signal(SIGHUP, handle_hangup_signal);

This fixes my bug. No 8 second delay, my clean-shutdown is executed.

However I wonder if there is a more clean gtk3 solution? Is it fine to use g_application_hold(), or is there some better gtk3 way to launch something in daemon-mode ?

Solution

  • Finally I know the reason for this strange behavior. It was caused by a direct gtk_main_quit(), triggered by the session-manager.

    If a g_application_release(..). is executed one line before, there is no logout-delay any more.

    Actually even a Gtk-CRITICAL got triggered by this gtk_main_quit():

    Gtk-CRITICAL **: gtk_main_quit: assertion 'main_loops != NULL' failed

    Till now I just did not see the message because the session-manager already closed the owning console.