MATLAB Programming Fundamentals - MathWorks

Capture Information About Exceptions

In this section...

“Overview” on page 26-5

“The MException Class” on page 26-5

“Properties of the MException Class” on page 26-6

“Methods of the MException Class” on page 26-14

Overview

When MATLAB throws an exception, it captures information about the cause in a data

structure called an MException object. This object is an instance of the MATLAB

MException class. You can access the MException object by catching the exception

before your program aborts and accessing the object constructed for this particular error

via the catch command. When throwing an exception in response to an error in your own

code, you will have to create a new MException object and store information about the

error in that object.

This section describes the MException class and objects constructed from that class.

Information on how to use this class is presented in later sections on “Respond to an

Exception” on page 26-19 and “Throw an Exception” on page 26-16.

The MException Class

The figure shown below illustrates one possible configuration of an object of the

MException class. The object has five properties: identifier, message, stack,

cause, and Correction. Each of these properties is implemented as a field of the

structure that represents the MException object. The stack field is an N-by-1 array of

additional structures, each one identifying a function, and line number from the call

stack. The cause field is an M-by-1 cell array of MException objects, each representing

an exception that is related to the current one.

See “Properties of the MException Class” on page 26-6 for a full description of these

properties.

Capture Information About Exceptions