Hallo, Welt! (C)

Hallo, Welt! (C) Susanna Huhtanen ihmis.suski@gmail.com 2012 Tiffany Antopolski tiffany.antopolski@gmail.com Bastian Ilsø bastianilso@gnome.org Creating a small "Hello, World" application using GTK+. Mario Blättermann mario.blaettermann@gmail.com 2011, 2013 Hello world

For a detailed walk-through of creating a GTK+ dialog in C, see Getting Started with GTK+

Writing a hello world GTK+ dialog in C can be done as seen in the code sample below:


    #include <gtk/gtk.h>

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

  window = gtk_application_window_new (app);
  label = gtk_label_new ("Hello GNOME!");
  gtk_container_add (GTK_CONTAINER (window), label);
  gtk_window_set_title (GTK_WINDOW (window), "Welcome to GNOME");
  gtk_window_set_default_size (GTK_WINDOW (window), 200, 100);
  gtk_widget_show_all (window);
}

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

  app = gtk_application_new (NULL, 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;
}

GtkApplication initializes GTK+. It also connects the x button that's automatically generated along with the window to the "destroy" signal. We can start building our first window. We do this by creating a variable called window and assigning it a gtk_application_window_new. The window title can be any string you want it to be. To be on the safe side, it's best to stick to UTF-8 encoding. The code above will create a dialog window similar to what can be seen below: