MATLAB Programming Fundamentals - MathWorks

Argument Checking in Nested Functions

This topic explains special considerations for using varargin, varargout, nargin, and

nargout with nested functions.

varargin and varargout allow you to create functions that accept variable numbers of

input or output arguments. Although varargin and varargout look like function names,

they refer to variables, not functions. This is significant because nested functions share

the workspaces of the functions that contain them.

If you do not use varargin or varargout in the declaration of a nested function, then

varargin or varargout within the nested function refers to the arguments of an outer

function.

For example, create a function in a file named showArgs.m that uses varargin and has

two nested functions, one that uses varargin and one that does not.

function showArgs(varargin)

nested1(3,4)

nested2(5,6,7)

function nested1(a,b)

disp('nested1: Contents of varargin{1}')

disp(varargin{1})

end

function nested2(varargin)

disp('nested2: Contents of varargin{1}')

disp(varargin{1})

end

end

Call the function and compare the contents of varargin{1} in the two nested functions.

showArgs(0,1,2)

nested1: Contents of varargin{1}

0

nested2: Contents of varargin{1}

5

Argument Checking in Nested Functions