Unwind-protect - Frequently asked questions about Octave (with answers)
Description: Frequently asked questions about Octave (with answers)

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### 5.9 Unwind-protect

Octave supports a limited form of exception handling modeled after the unwind-protect form of Lisp. The general form of an `unwind_protect` block looks like this:

         unwind_protect
           body
         unwind_protect_cleanup
           cleanup
         end_unwind_protect

Where body and cleanup are both optional and may contain any Octave expressions or commands. The statements in cleanup are guaranteed to be executed regardless of how control exits body.

The `unwind_protect` statement is often used to reliably restore the values of global variables that need to be temporarily changed.

Matlab can be made to do something similar with their `OnCleanUp` function that was introduced in 2008a. Octave also has `onCleanup` since version 3.4.0.