A nonlocal exit is a transfer of control from one point in a program to another remote point.
Nonlocal exits unbind all variable bindings made by the constructs being exited.
Catch and Throw Nonlocal exits for the program's own purposes. Examples of Catch Showing how such nonlocal exits can be written. Errors How errors are signaled and handled. Cleanups Arranging to run a cleanup form if an error happens.