Changing function logic parameters depending on outputs

If I have a function with 3 output arguments

[a,b,c] = fun(x)

I want the function only to calculate a,b,c if I actually call for them i.e. if I only want "c" I want to be able to call

[~,~,c] = fun(x)

without fun calculating a and b

what logical function can I use based on the specific outputs requested to achieve this? Probably a fairly trivial question but I can't find the answer.

Answer 1

[Thorsten]

You can use the istilde from http://biorobots.cwru.edu/personnel/adh/stackoverflow/04/ with the caveat that it works just in functions or scripts, but not from the command line, as described in http://stackoverflow.com/questions/19498911/how-to-determine-if-an-output-of-a-function-call-is-unused-matlab

[David H]

Thanks, that seems to do what I was looking for.