Code:

---

var mySize[3];
entity* ent0;
/************************************
	efSize0
*************************************/
function efSize0(_ent, &_size) {
	if (_ent == 0) { return(0); }
	ent0 = _ent;
	_size[0] = ent0.max_x - ent0.min_x;
	_size[1] = ent0.max_y - ent0.min_y;
	_size[2] = ent0.max_z - ent0.min_z;
	return(1);
}
// ...
// efSize0(my, mySize);
// mySize.x <- my length
// mySize.y <- my width
// mySize.z <- my height

---

edited: it was supposed to be 'modular'