main.cpp

#include <gtk/gtk.h>
 
static void print_hello (GtkWidget *widget,  gpointer   data) {
    g_print ("Hello World\n");
}

static void activate (GtkApplication *app, gpointer user_data) {
    GtkWidget *window;
    GtkWidget *button;
    GtkWidget *button_box;

    window = gtk_application_window_new (app);
    gtk_window_set_title (GTK_WINDOW (window), "Window");
    gtk_window_set_default_size (GTK_WINDOW (window), 200, 200);

    button_box = gtk_button_box_new (GTK_ORIENTATION_HORIZONTAL);
    gtk_container_add (GTK_CONTAINER (window), button_box);

    button = gtk_button_new_with_label ("Hello World");
    g_signal_connect (button, "clicked", G_CALLBACK (print_hello), NULL);
    g_signal_connect_swapped (button, "clicked", G_CALLBACK (gtk_widget_destroy), window);
    gtk_container_add (GTK_CONTAINER (button_box), button);

    gtk_widget_show_all (window);
}

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

    return status;
}