Return several arguments for another function by a single function

Question

This question was closed as exact duplicate since I chose a misleading question title. It was not wrong but suggested an issue often discussed, e.g. in this question. Since

Answer 1

It is not possible, C++ does not allow to provide 3 return values natively that can be used as 3 separate input arguments for another function.

But there are 'tricks' to return multiple values. Although none of these provide a perfect solution for your question, as they are not able to be used as a single argument to length() without modifying length().

Use a container object, like a struct, tuple or class

typedef struct { int a,b,c; } myContainer;

myContainer arguments(int x, int y, int z) {
  myContainer result;
  result.a = 1;
  // etc
  return result;
}

myContainer c = arguments(x, y, z);
length(c.a, c.b, c.c);

The trick is to overload the length() function, so it looks like you can use it with a single argument:

void length(myContainer c) {
  length(c.a, c.b, c.c);
}

length(arguments());

Of course you could optimize it further, by using inline, macros, and what not.

I know it is still not exactly what you want, but I think this is the closest approach.