matlab - suppress error message backtrace

Question

I try to check if input argument is of specific type and throw error message like:

function test(input)
    if ~ischar(input)
        error('%s is invalid input type.', class(input));
    end
end

But Matlab shows error message with backtrace -information:

>> test(1)
Error using test (line 3)
double is invalid input type.

How can I turn off the line Error using test (line 3) ?

I'm looking for something similar to off backtrace with warning : warning off backtrace; .

Answer 1

I'm not sure you can. The closest I got was by defining my own error structure:

testerr.message = 'test';
testerr.identifier = '';
testerr.stack.file = '';
testerr.stack.name = 'Test Thing';
testerr.stack.line = 1;

error(testerr)

Which returns:

Error using Test Thing
test

As long as you keep the file field blank it will not display the line specified in the stack.

One potential workaround could be a combination of fprintf and return , courtesy of Undocumented MATLAB :

function test(input)
    if ~ischar(input)
        fprintf(2, '%s is invalid input type.\n', class(input));
        return
    end
end

Depending on where this check resides in your real function you might need to get creative with how it exits, since return only kicks you back to the invoking function. Probably have it output a True / False flag?