VtLock --
set cursor to watch cursor, lock out user input
Syntax
VtLock
Description
Sets the cursor to the watch cursor and locks the application
(that is, the application will no longer accept input from the user).
New dialogs that are about to pop up are also automatically locked.
To unlock the application, see
VtUnLock(VTCL).
VtLock can be called multiple times. Calling VtUnLock
will free all of the current locks. If you only wish to unlock
one layer of the nested locks, use VtUnLock -once.