Various errors can be generated. The mnemonic field is a string

normally used as a tag related to the particular message.

From the command line, you can obtain the message identifier for an

error that has been issued using the MException.last function.

See also MException, MException/throw, try, catch, sprintf, dbstop,

errordlg, warning, disp, dbstack.

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doc error

<Mexception> - Constructs MATLAB exception object.

MException Capture error information.

ME = MException(MSGID, ERRMSG, V1, V2, ..., VN) captures information

about a specific error and stores it in MException object ME.

MSGID is a character string that uniquely identifies the source of the

error, and is composed of at least two substrings separated by a colon

(such as COMPONENT:MNEMONIC). For more information, type HELP ERROR

and see MESSAGE IDENTIFIERS.

ERRMSG is a character string that informs the user about the cause of

the error and can suggest how to correct the faulty condition. The

ERRMSG string can include escape sequences such as \t or \n, as well as

any of the format conversion specifiers supported by the SPRINTF

function, such as %s or %d. For more information, type HELP SPRINTF.

Inputs V1, V2, ..., VN provide values that replace any conversion

specifiers in the ERRMSG string.

Examples:

% Example 1 - Check the identifier of a MATLAB exception.

try

fid = fopen('noSuchFile.dat');

mydata = fread(fid);

fclose(fid);

catch ME

if strcmp(ME.identifier, 'MATLAB:FileIO:InvalidFid')

disp('Could not find the specified file.');

rethrow(ME);

end

end

% Example 2 - Create your own exception.

inputstr = input('Type a variable name:', 's');

if ~exist(inputstr, 'var')

ME = MException('MyComponent:noSuchVariable', ...

'Variable %s not found', inputstr);

throw(ME);

end

MException methods:

throw - Issue exception and terminate function

rethrow - Reissue existing exception and terminate function

throwAsCaller - Issue exception as if from calling function

addCause - Record additional causes of exception

getReport - Get error message for exception

last - Return last uncaught exception

MException public fields:

identifier - Character string that uniquely identifies the error

message - Formatted error message that is displayed

stack - Structure containing stack trace information

cause - Cell array of MExceptions that caused this exception

See also error, assert, try, catch, dbstack.

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doc Mexception

<assert> - Generate an error when a condition is violated.

ASSERT Generate an error when a condition is violated.

ASSERT(EXPRESSION) evaluates EXPRESSION and, if it is false, displays the

error message 'Assertion Failed'.

ASSERT(EXPRESSION, ERRMSG) evaluates EXPRESSION and, if it is false,

displays the string contained in ERRMSG. When ERRMSG is the last input to

ASSERT, MATLAB displays it literally, without performing any substitutions

on the characters in ERRMSG.

ASSERT(EXPRESSION, ERRMSG, VALUE1, VALUE2, ...) evaluates EXPRESSION and, if