destroy-notify.c

// Destroy Notify Demo
// Adapted from GTK 3 Tutorial
//
// Compile with:
// gcc `pkg-config --cflags gtk+-3.0` -o destroy-notify destroy-notify.c `pkg-config --libs gtk+-3.0`
//
// Output:
// $ ./destroy-notify
// Source Func
// Destroy Notify
//
// This demonstrates that by returning FALSE from the function we remove
// the source and therefore call destroy notify to do our cleanup.

#include <gtk/gtk.h>

static void
activate (GtkApplication* app,
          gpointer        user_data)
{
    // Just to put something on the screen
    GtkWidget *window = gtk_application_window_new (app);

    gtk_window_set_title (GTK_WINDOW (window), "Window");
    gtk_window_set_default_size (GTK_WINDOW (window), 200, 200);
    gtk_widget_show_all (window);
}

static gboolean
source_func (gpointer user_data)
{
    // We print out "Source Func" to the console,
    // then remove the source by returning FALSE.
    // This will trigger destroy_notify for us.
    g_print("Source Func\n");
    return FALSE;
}

static void
destroy_notify (gpointer user_data)
{
    // If the source is removed successfully, destroy
    // notify is called. We can free resources here.
    g_print("Destroy Notify\n");
}

int
main (int    argc,
      char **argv)
{
    GtkApplication *app;
    int status;

    app = gtk_application_new ("org.gtk.example", G_APPLICATION_FLAGS_NONE);
    g_signal_connect (app, "activate", G_CALLBACK (activate), NULL);

    // Add asynchronous timeout function to main loop
    g_timeout_add_full (0, 1000, source_func, NULL, destroy_notify);

    status = g_application_run (G_APPLICATION (app), argc, argv);
    g_object_unref (app);

    return status;
}