Programming and Data Types

Saving and Loading Function Handles

You can use the MATLAB save and load functions to save function handles to MAT files, and then load them back into your MATLAB workspace later on. This example shows an array of function handles saved to the file, savefile, and then restored.

• fh_array = [@sin @cos @tan];
  save savefile fh_array;
  clear
  
  load savefile
  whos
    Name             Size         Bytes  Class
    fh_array       1x3             48  function_handle array
  Grand total is 3 elements using 48 bytes
  

Possible Effects of Changes Made Between Save and Load

If you load a function handle that you saved in an earlier MATLAB session, the following conditions could cause unexpected behavior:

• Any of the M-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 doesn't exist or is located in a different directory than on the system on which the handle was saved.
• You have overloaded the function with additional methods since the save was done. The function handle you just loaded doesn't know about the new methods.

In the first two cases, the function handle is now invalid, since it no longer maps to any existing source code. Although the handle is invalid, MATLAB still performs the load successfully and without displaying a warning. An attempt to evaluate the handle however results in an error.

Testing for Data Type

Handling Error Conditions