MATLAB Programming Fundamentals - MathWorks

Clean Up When Functions Complete

In this section...

“Overview” on page 26-24

“Examples of Cleaning Up a Program Upon Exit” on page 26-25

“Retrieving Information About the Cleanup Routine” on page 26-27

“Using onCleanup Versus try/catch” on page 26-28

“onCleanup in Scripts” on page 26-29

Overview

A good programming practice is to make sure that you leave your program environment

in a clean state that does not interfere with any other program code. For example, you

might want to

• Close any files that you opened for import or export.


• Restore the MATLAB path.


• Lock or unlock memory to prevent or allow erasing MATLAB function or MEX-files.


• Set your working folder back to its default if you have changed it.


• Make sure global and persistent variables are in the correct state.

MATLAB provides the onCleanup function for this purpose. This function, when used

within any program, establishes a cleanup routine for that function. When the function

terminates, whether normally or in the event of an error or Ctrl+C, MATLAB

automatically executes the cleanup routine.

The following statement establishes a cleanup routine cleanupFun for the currently

running program:

cleanupObj = onCleanup(@cleanupFun);

When your program exits, MATLAB finds any instances of the onCleanup class and

executes the associated function handles. The process of generating and activating

function cleanup involves the following steps:

(^1) Write one or more cleanup routines for the program under development. Assume for
now that it takes only one such routine.
26 Error Handling