MATLAB Programming

Message Identifiers
are a particular product or toolbox name, such as MATLAB or Control, or
perhaps the name of your company, such as TechCorp in the example above.
You can also use this field to specify a multilevel component. The statement
below has a three-level component followed by a mnemonic label:
TechCorp:TestEquipDiv:Waveform:obsoleteSyntax
Onepurposeofthecomponentfieldistoenableyoutoguaranteethe
uniqueness of each identifier. Thus, while MATLAB uses the identifier
MATLAB:divideByZero for its 'Divide by zero' warning, you could reuse the
divideByZero mnemonic by using your own unique component. For example,
warning('TechCorp:divideByZero', ...
'A sprocket value was divided by zero.')
Mnemonic Field
The mnemonic field is a string normally used as a tag relating to the particular
message. For example, when reporting an error resulting from the use
of ambiguous syntax, a mnemonic such as ambiguousSyntax might be
appropriate:
error('MATLAB:ambiguousSyntax', ...
'Syntax %s could be ambiguous.\n', inputstr)
Using Message Identifiers with lasterror
Oneuseofmessageidentifiersistoenablethelasterror and lasterr
functions to better identify the source of an error. These functions return
a message identifier, and you can use the combination of component and
mnemonic parts of that identifier to identify both a broad category of errors
and a specific instance within that category, respectively.
The first step in using this feature is to determine which of your error
messages need this type of identification and then tag each with an identifier.
You do this by specifying a message identifier argument (msg_id, below)
along with the error message in your calls to error. Either form shown
below is acceptable. The latter form uses formatting conversion characters as
described in “Formatted Message Strings” on page 8-14.
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