#include <gtk/gtk.h>

static void buttonPressed(GtkWidget *widget, gpointer data) {
    gtk_button_set_label(GTK_BUTTON(widget), "I've been pressed!");
}

static void destroy(GtkWidget *widget, gpointer data) {
    gtk_main_quit ();
}

int main(int argc, char **argv) {
    GtkWidget *button, *win;
    
    gtk_init(&argc, &argv);

    win = gtk_window_new(GTK_WINDOW_TOPLEVEL);
    button = gtk_button_new_with_label("Hello, World. Press me");
    gtk_container_add(GTK_CONTAINER(win), button);
    g_signal_connect (G_OBJECT(button), "pressed",
		      G_CALLBACK(buttonPressed), NULL);
    gtk_widget_show_all(win);
    g_signal_connect (G_OBJECT(win), "destroy",
		      G_CALLBACK(destroy), NULL);

    gtk_main();
    return 0;
}