The EZ widget data structure reserves two fields for
applications to hook in client data. One is of type
void *
and the other is of type int
. Also,
there is a event handler list and three callback lists:
a callback list, a destroy callback list and a motion callback
list. EZwgl contains routines for registering
them. However, under certation conditions, they may also be
set by EZ_ConfigureWidget
.
void *
to
a widget data structure.
int
to
a widget data structure.
EZ_CallBack
procedure and
a void *
client data to be passed to the callback.
Note: this option removes all existing callbacks before
registering the new one. If your widget has multiple callbacks,
you'll have to use EZ_AddWidgetCallBack
.
EZ_AddWidgetCallBack
instead. This option needs
two values, a procedure of type EZ_CallBack
and
a client data of type void *
.
EZ_AddWidgetCallBack
instead.
This option needs two values, a procedure of
type EZ_CallBack
and a client data of type void *
.
EZ_EventHandler
and a
void *
client data.
As for callbacks, this option removes all the currently
registered event handlers before registering the new one.
Therefore, you must use EZ_AddEventHandler
to register your event handlers if your widget has multiple
event handlers.