Pointers in function parameters

How to pass a pointer to structure to a function? For example in this function I need to change Vector3 value:

function ChangeVector( vec : Vector3 ) { vec.x = 0; }

function Main( ) { var vec = Vector3( 1, 1, 1 ); ChangeVector( vec );

... vec.x should be 0.

As far as I look at Collider.Raycast which is:

function Raycast (ray : Ray, out hitInfo : RaycastHit, distance : float) : bool;

and where RaycastHit is structure it is possible to do it.

PS: Is it possible to do this for simple variables like "int"?

This is possible in C#, but I'm not sure about UnityScript.

Why not just have ChangeVector return a new Vector3?

function ChangeVector( vec : Vector3 ) {
    vec.x = 0;
    return vec;

use the "out" keyword or "ref" keyword to pass by reference. yes it's possible to do that. structures and simple values are passed by value normally and you can change that in this manner.

changevector (ref v);