File:GTK+ Hallo Welt.png

#include <gtk/gtk.h>
#include <stdio.h>

void button_geklickt(GtkWidget *button_widget, gpointer data) {
    printf("Button \"%s\" geklickt!\n",
       gtk_button_get_label(GTK_BUTTON(button_widget)) );
    gtk_main_quit();
}

int main (int argc, char *argv[]) {
    gtk_init(&argc, &argv);

    GtkWidget *window;
    GtkWidget *button;

    window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
    gtk_window_set_title(GTK_WINDOW(window), "Hallo Welt!");
    gtk_container_set_border_width(GTK_CONTAINER(window), 10);
    g_signal_connect_swapped(G_OBJECT(window), "destroy", G_CALLBACK (gtk_main_quit), NULL);

    button = gtk_button_new_with_label("Hallo Wikipedia!");
    g_signal_connect(G_OBJECT(button), "clicked", G_CALLBACK(button_geklickt), NULL);
    gtk_widget_show(button);

    gtk_container_add(GTK_CONTAINER(window), button);
    gtk_widget_show(window);

    gtk_main();
    return 0;
}