main.cpp

#include <gtk/gtk.h>
#include <glib/gstdio.h>

static void
print_hello(GtkWidget *widget,
            gpointer data)
{
    g_print("Hello World\n");
}

static void
quit_cb(GtkWindow *window)
{
    gtk_window_close(window);
}

static void
activate(GtkApplication *app,
         gpointer user_data)
{
    /* Construct a GtkBuilder instance and load our UI description */
    GtkBuilder *builder = gtk_builder_new();
    gtk_builder_add_from_file(builder, "builder.ui", NULL);

    /* Connect signal handlers to the constructed widgets. */
    GObject *window = gtk_builder_get_object(builder, "window");
    gtk_window_set_application(GTK_WINDOW(window), app);

    GObject *button = gtk_builder_get_object(builder, "button1");
    g_signal_connect(button, "clicked", G_CALLBACK(print_hello), NULL);

    button = gtk_builder_get_object(builder, "button2");
    g_signal_connect(button, "clicked", G_CALLBACK(print_hello), NULL);

    button = gtk_builder_get_object(builder, "quit");
    g_signal_connect_swapped(button, "clicked", G_CALLBACK(quit_cb), window);

    gtk_widget_set_visible(GTK_WIDGET(window), TRUE);

    /* We do not need the builder any more */
    g_object_unref(builder);
}

int main(int argc,
         char *argv[])
{
#ifdef GTK_SRCDIR
    g_chdir(GTK_SRCDIR);
#endif

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

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

    return status;
}