Installs a key snooper function, which will get called on all key events before delivering them normally.
a #GtkKeySnoopFunc
data to pass to @snooper
Return: a unique id for this key snooper for use with gtk_key_snooper_remove().
Deprecated: Key snooping should not be done. Events should be handled by widgets.
See Implementation
Installs a key snooper function, which will get called on all key events before delivering them normally.