MATLAB Programming

8 Error Handling
Handling and Recovering from an Error
The catch segment of a try-catch block needs to effectively handle any
errors that may be caught by the preceding try. Frequently, you will want
to simply report the error and stop execution. This prevents erroneous data
from being propagated into the remainder of the program.
This section covers
• “Reporting an Error” on page 8-4
• “Identifying the Cause” on page 8-5
• “Regenerating an Error” on page 8-8
Reporting an Error
To report an error and halt program execution, use the MATLAB error
function. You determine what the error message will be by specifying it as an
input to the error function in your code. For example,
if n < 1
error('n must be 1 or greater.')
end
displays the message shown below when n is equal to zero.
??? n must be 1 or greater.
Formatted Message Strings
The error message string that you specify can also contain formatting
conversion characters, such as those used with the MATLAB sprintf
function. Make the error string the first argument, and then add any
variables used by the conversion as subsequent arguments.
error('formatted_errormsg', arg1, arg2, ...)
Forexample,ifyourprogramcannotfind a specific file, you might report
the error with
error('File %s not found', filename);
8-4