`nargchk`

Old-style check of the number of input arguments; superseded by narginchk.

Syntax

msg = nargchk(minargs, maxargs, numargs)

Returns an error message if numargs lies outside minargs to maxargs, otherwise an empty value.

msg = nargchk(minargs, maxargs, numargs, 'struct')

Returns the problem as a structure with message and identifier fields.

Description

nargchk only builds a message; it does not raise an error. The caller must test the result and call error. New code should use narginchk, which throws the error directly with the standard text.

Input arguments

minargs: Smallest acceptable count.
maxargs: Largest acceptable count; Inf means no limit.
numargs: The actual count, normally nargin.

Output arguments

msg: Error message text, or an empty value when the count is acceptable.

Example

Calling it inside a function

function r = scale(x, k)
    nargchk(1, 2, nargin);
    if nargin < 2
        k = 10;
    end
    r = x * k;
end
disp(scale(4))
disp(scale(4, 3))

Output

    40
    12

Notes

In MatLivre nargchk is accepted but performs no check, so wrong argument counts are not reported. Use error yourself if a hard failure is needed.

nargchk