You can save and load function handles in a MAT-file using the MATLAB® save and load functions. If you load a function handle that you saved in an earlier MATLAB session, the following conditions could cause unexpected behavior:
Any of the files that define the function have been moved, and thus no longer exist on the path stored in the handle.
You load the function handle into an environment different from that in which it was saved. For example, the source for the function either does not exist or is located in a different folder than on the system on which the handle was saved.
In both of these cases, the function handle is now invalid because it is no longer associated with any existing function code. Although the handle is invalid, MATLAB still performs the load successfully and without displaying a warning. Attempting to invoke the handle, however, results in an error.
If you create a handle to a function that is not on the MATLAB path, or if you load a handle to a function that is no longer on the path, MATLAB catches the error only when the handle is invoked. You can assign an invalid handle and use it in such operations as func2str. MATLAB catches and reports an error only when you attempt to use it in a runtime operation.