• Every signal is uniquely identified by a name, Event Handling in Glade Kwangwoo Choi Department of Physics Kangwon National University • Signals are a way to get notification when something happens and to customize object behavior according to the user's needs. • Every signal is uniquely identified by a name, “Class_name::Signal_name”, where Signal_name might be something like “clicked”.

Basic Terminology signal A class method, e.g. GtkButton::clicked. More precisely it is a unique class-branch/signal-name pair. This means you may not define a signal handler for a class which derives from GtkButton that is called clicked, but it is okay to share signals names if they are separate in the class tree. default handler The object's internal method which is invoked when the signal is emitted. user-defined handler A function pointer and data connected to a signal (for a particular object). There are really two types: those which are connected normally, and those which are connected by one of the connect_after functions. emission the whole process of emitting a signal, including the invocation of all the different handler types mentioned above. signal id The unique positive (nonzero) integer used to identify a signal. It can be used instead of a name to many functions for a slight performance improvement.

Use the “delete_event” Delete_event: close Windows

Click “Add” Gboolean on_window1_delete_event (GtkWidget *widget, GdkEvent *event, gpointer user_data) { gtk_exit( 0 ); return FALSE; }

Summary • Signals are a way to get notification when something user's happens and to customize object behavior according to the needs.