How do functions with multiple outputs work?

I was trying to write matlab functions but I sometimes find myself doing something really silly(in my opinion). Consider a function of multiple outputs:

function [ F_X, Z, A ] = f(obj,X)
    F_X = magic(5);
    Z = ones(5);
    A = 2*ones(5); 
end

and then I have some wrapper function like:

function [ F_X ] = get_first_arg(obj,X)
 [F_X, ~, ~] = obj.f(X);
end

to get the first argument so that when I want to do use only the first argument I do

g(obj.get_first_arg(X))

instead of:

[F_X, ~, ~] = obj.f(X)
g(F_X)

this seems really silly. I have tried googling for this but didn't find anything I could use. How does matlab know that I only want the first object/matrix/data thing in output tuple?

Answer 1

[Star Strider]

If you just call your function as:

F_X = f(obj,X);

by default, only the first argument will be returned. You only need the tilde (~) if you do not want to return the first argument, for example:

[ ~, Z, A ] = f(obj,X);

[Brando Miranda]

Where is documentation discussing this?

[Star Strider]

Here:

Ignore Function Outputs