MATLAB Programming

8 Error Handling
Warnings
Like error, thewarning function alerts the user of unexpected conditions
detected when running a program. However, warning does not halt the
execution of the program. It displays the specified warning message and
then continues.
This section covers
• “Reporting a Warning” on page 8-14
• “Identifying the Cause” on page 8-15
Reporting a Warning
Use warning in your code to generate a warning message during execution.
Specify the message string as the input argument to warning. For example,
warning('Input must be a string')
Warnings also differ from errors in that you can disable any warnings that
you don’t want to see. You do this by invoking warning with certain control
parameters. See “Warning Control” on page 8-16 for more information.
Formatted Message Strings
The warning message string that you specify can also contain formatting
conversion characters, such as those used with the MATLAB sprintf
function. Make the warning string the first argument, and then add any
variables used by the conversion as subsequent arguments.
warning('formatted_warningmsg', arg1, arg2, ...)
For example, if your program cannot process a given parameter, you might
report a warning with
warning('Ambiguous parameter name, "%s".', param)
MATLAB converts special characters (like \n and %d) in the warning message
string only when you specify more than one input argument with warning.
See “Formatted String Conversion” on page 8-5 for information.
8-14