Add GTK+ example

gtk/Makefile

@@ -0,0 +1,14 @@
+PACKAGE = helloworld
+OBJECTS = helloworld.o
+CFLAGS  = `pkg-config --cflags gtk+-3.0`
+LDADD   = `pkg-config --libs gtk+-3.0`
+
+helloworld: $(OBJECTS)
+	${CC} -o ${PACKAGE} ${OBJECTS} ${LDADD}
+
+.c.o:
+	${CC} ${CFLAGS} -c $<
+
+
+clean:
+	rm -f helloworld *.o

gtk/helloworld.c

@@ -0,0 +1,42 @@
+#include <gtk/gtk.h>
+ 
+int main (int argc, char *argv[])
+{
+    GtkWidget *window;
+    GtkWidget *label;
+ 
+    gtk_init(&argc, &argv);
+ 
+    /* Create the main, top level window */
+    window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
+ 
+    /* Give it the title */
+    gtk_window_set_title(GTK_WINDOW(window), "Hello, world!");
+ 
+    /*
+    ** Map the destroy signal of the window to gtk_main_quit;
+    ** When the window is about to be destroyed, we get a notification and
+    ** stop the main GTK+ loop by returning 0
+    */
+    g_signal_connect(window, "destroy", G_CALLBACK(gtk_main_quit), NULL);
+ 
+    /*
+    ** Assign the variable "label" to a new GTK label,
+    ** with the text "Hello, world!"
+    */
+    label = gtk_label_new("Hello, world!");
+ 
+    /* Plot the label onto the main window */
+    gtk_container_add(GTK_CONTAINER(window), label);
+ 
+    /* Make sure that everything, window and label, are visible */
+    gtk_widget_show_all(window);
+ 
+    /*
+    ** Start the main loop, and do nothing (block) until
+    ** the application is closed
+    */
+    gtk_main();
+ 
+    return 0;
+}