onCleanup

Cleanup tasks upon function completion

Syntax

cleanupObj = onCleanup(cleanupFun)

Description

cleanupObj = onCleanup(cleanupFun) creates an object that, when destroyed, executes the function cleanupFun. MATLAB^® implicitly clears all local variables at the termination of a function, whether by normal completion, or a forced exit, such as an error, or Ctrl+C.

If you reference or pass cleanupObj outside your function, then cleanupFun does not run when that function terminates. Instead, it runs whenever MATLAB destroys the object.

Examples

Close a Figure After Executing Function

Save the following code in action.m and type action in the Command Window.

function action
disp('Display Figure')
f = figure;
cleanup = onCleanup(@()myCleanupFun(f));
pause(1)
end

function myCleanupFun(f)
disp('Close Figure')
close(f)
end

Display Figure
Close Figure

Switch Directories After Executing Function

Pass your own script to the onCleanup object so that it executes when MATLAB destroys the cleanup object.

Save the following code in cleanup.m.

cd(tempdir)
disp('You are now in the temporary folder')

Save the following code in youraction.m and type youraction in the Command Window.

function youraction
cleanup = onCleanup(@cleanup);
disp('Execute Code')
end

Execute Code
You are now in the temporary folder

Input Arguments

cleanupFun — Cleanup task

function handle

Cleanup task, specified as a handle to a function.

You can declare any number of onCleanup objects in a program file. However, if the cleanup tasks depend on the order of execution, then you should define only one object that calls a script or function, containing the relevant cleanup commands.

You should use an anonymous function handle to call your cleanup task. This allows you to pass arguments to your cleanup function.

Example: @()fclose('file.m')

Example: @user_script

Data Types: function_handle

Tips

• Avoid using nested functions during cleanup. MATLAB can clear variables used in nested functions before the cleanup function tries to read from them.

• If your program contains multiple cleanup objects, MATLAB does not guarantee the order that it destroys these objects. If the order of your cleanup functions matters, define one onCleanup object for all the tasks.

• If you save an onCleanup object, MATLAB displays a warning and does not save the cleanupFun cleanup task.

Extended Capabilities

C/C++ Code Generation

Generate C and C++ code using MATLAB® Coder™.

Usage notes and limitations:

• The onCleanup is implemented with destructors. For more information, see Code Generation for Handle Class Destructors (MATLAB Coder).

Thread-Based Environment

Run code in the background using MATLAB® backgroundPool or accelerate code with Parallel Computing Toolbox™ ThreadPool.

This function fully supports thread-based environments. For more information, see Run MATLAB Functions in Thread-Based Environment.

Version History

Introduced in R2008a

R2025a: Cancel Cleanup Tasks

The cancel object function cancels any cleanup tasks specified by the onCleanup object and prevents them from being executed when the object is destroyed.