Confused about Exception handling

Code:

---

void x :: setValues (unsignedshort m_headLight) throw (OutOfRangeException)
{
        try
        {
                if (m_headLight > 1)
                {
                        throw OutOfRangeException (WARNINGEXP, "'m_headLight' is out of range", "Value should be either 0 or 1", __FILE__, __LINE__);
                }
        }
        d_y.m_headLight = m_headLight;
}

---

The above code will work even if I remove the following statement in RED color

Code:

---

void x :: setValues (unsignedshort m_headLight) throw (OutOfRangeException)

---

Then What is the purpose of writing that statement ? Kindly explain !

It used to be some sort of method to tell the compiler that a function throws a specific object. The compiler could then also enforce that only that kind of exception would be thrown from the function.
Unfortunately, this isn't really the case. The exception specifier is hardly used, or implemented, at all. It would be better to simply ignore it, unless you want it there for decorative purposes (such as saying this function will throw only these objects; though you don't actually need to enforce it).

In summary, the red part is not needed. It is an optional add-on to give the compiler extra information, but not all compilers enforce it, and even if they do, they enforce it at runtime.
It is not a requirement to have it to throw an exception.

Elysia

Many thanks to you for the enlightening reply :)