nargout of builtin set

The function set() returns either zero output (when 3 arguments are supplied), either 1 output (when 1 argument is supplied). Hence I thought nargout(@set) was negative, since a variable number of outputs is supposed to rely on the varargout mechanism. However, nargout(@set)= 1 !

I don't understand. How can Matlab supply a function with varying number of outputs that does not use varargout ? Is it a bug in nargout ?

Thank you

Answer 1

[Walter Roberson]

Varying number of outputs do not need to rely on varargout. It is completely legal to have something like

   function r = set(h, varargin)
     ....
     tr = ....
     if nargout > 0; r = tr; end
  end

varargout is used for arguments that are not named in the output list; ndgrid() is an example where it does not make sense to have the function code name arguments.

[Nath]

Very clear. Thank you very much ! It makes me realize how useless nargout(f) is for a generic functionnal programming approach (say for instance generic function decorator)