What is the point of `void func() throw(type)`?

Question

I know this is a valid c++ program. What is the point of the throw in the function declarement? AFAIK it does nothing and isnt used for anything.

#include &l         


        

Answer 1

It specifies that any std::exception can be thrown from func(), and nothing else. If something else is thrown, it will call an unexpected() function which by default calls terminate().

What this means is that throwing something else will almost certainly terminate the program, in the same manner as an uncaught exception, but the implementation will have to enforce this. This is normally much the same as putting a try{...}catch(){...} block around func(), which can inhibit performance.

Usually, exception specifications aren't worth it, according to the Guru of the Week column about it. The Boost guidelines say that there might be a slight benefit with a blank throws() for a non-inline function, and there are disadvantages.