XtAppAddActionHook, XtRemoveActionHook - register an action hook procedure
#include <X11/Intrinsic.h>
XtActionHookId XtAppAddActionHook(XtAppContext app_context, XtActionHookProc proc, XtPointer client_data);
void XtRemoveActionHook(XtActionHookId id);
Specifies the application context.
Specifies the action hook procedure.
Specifies the application-specific data to be passed to the action hook.
XtAppAddActionHook adds the specified procedure to the front of a list maintained in the application context. In the future, when an action routine is about to be invoked for any widget in this application context, either through the translation manager or via XtCallActionProc, the action hohok procedures will be called in reverse order of registration jut prior to invoking the action routine.
Action hook procedures are removed automatically and the XtActionHookId s destroyed when the application context in which they were added is destroyed.
XtRemoveActionHook removes the specified action hook procedure from the list in which it was registered.
X Toolkit Intrinsics - C Language Interface
Xlib - C Language X Interface