gtk/examples/helloworld/helloworld.c

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/* This file extracted from the GTK tutorial. */
/* helloworld.c */
#include <gtk/gtk.h>
/* this is a callback function. the data arguments are ignored in this example.
* More on callbacks below. */
void hello (GtkWidget *widget, gpointer data)
{
g_print ("Hello World\n");
}
gint delete_event(GtkWidget *widget, gpointer data)
{
g_print ("delete event occured\n");
/* if you return FALSE in the "delete_event" signal handler,
* GTK will emit the "destroy" signal. Returning TRUE means
* you don't want the window to be destroyed.
* This is useful for popping up 'are you sure you want to quit ?'
* type dialogs. */
/* Change TRUE to FALSE and the main window will be destroyed with
* a "delete_event". */
return (TRUE);
}
/* another callback */
void destroy (GtkWidget *widget, gpointer data)
{
gtk_main_quit ();
}
int main (int argc, char *argv[])
{
/* GtkWidget is the storage type for widgets */
GtkWidget *window;
GtkWidget *button;
/* this is called in all GTK applications. arguments are parsed from
* the command line and are returned to the application. */
gtk_init (&argc, &argv);
/* create a new window */
window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
/* when the window is given the "delete_event" signal (this is given
* by the window manager (usually the 'close' option, or on the
* titlebar), we ask it to call the delete_event () function
* as defined above. The data passed to the callback
* function is NULL and is ignored in the callback. */
gtk_signal_connect (GTK_OBJECT (window), "delete_event",
GTK_SIGNAL_FUNC (delete_event), NULL);
/* here we connect the "destroy" event to a signal handler.
* This event occurs when we call gtk_widget_destroy() on the window,
* or if we return 'TRUE' in the "delete_event" callback. */
gtk_signal_connect (GTK_OBJECT (window), "destroy",
GTK_SIGNAL_FUNC (destroy), NULL);
/* sets the border width of the window. */
gtk_container_border_width (GTK_CONTAINER (window), 10);
/* creates a new button with the label "Hello World". */
button = gtk_button_new_with_label ("Hello World");
/* When the button receives the "clicked" signal, it will call the
* function hello() passing it NULL as it's argument. The hello()
* function is defined above. */
gtk_signal_connect (GTK_OBJECT (button), "clicked",
GTK_SIGNAL_FUNC (hello), NULL);
/* This will cause the window to be destroyed by calling
* gtk_widget_destroy(window) when "clicked". Again, the destroy
* signal could come from here, or the window manager. */
gtk_signal_connect_object (GTK_OBJECT (button), "clicked",
GTK_SIGNAL_FUNC (gtk_widget_destroy),
GTK_OBJECT (window));
/* this packs the button into the window (a gtk container). */
gtk_container_add (GTK_CONTAINER (window), button);
/* the final step is to display this newly created widget... */
gtk_widget_show (button);
/* and the window */
gtk_widget_show (window);
/* all GTK applications must have a gtk_main(). Control ends here
* and waits for an event to occur (like a key press or mouse event). */
gtk_main ();
return 0;
}