In C++, it is possible to return a reference from a function. Returning a reference can be useful in cases where we want to return a large object without incurring the cost of copying it.

To return a reference from a function, we simply specify the return type as a reference type. For example:

int& getLargest(int& x, int& y) {
    if (x > y) {
        return x;
    } else {
        return y;
    }
}

In this example, the getLargest function takes two integer references as input, compares them, and returns a reference to the larger of the two. Because the return type is int&, the function returns a reference to an int rather than a copy of an int.

It's important to note that when we return a reference from a function, we are returning a reference to a variable that is local to the function. If the reference is used outside of the function, the variable it refers to will have been destroyed, leading to undefined behavior. To avoid this, we can return a reference to a static or global variable, or allocate memory on the heap and return a reference to that. However, we must ensure that the object being referred to remains valid for as long as the reference is being used.