Semicolon in namespace. Necessary?

Question

when working with namespace, I need to finish it with a semicolon? When I put a forward declaration of a class into a namespace, for example, many people doesn't include a semicolon but, it seems to be optional.

Does semicolon add functionality or change the current functionality by adding or removing?

Thanks.

Answer 1

If semicolon is optional it doesn't change functionality, otherwise it you omit it you'll get a syntax error.

namespace A {
    class B; // forward declaration, semicolon is mandatory.

    class B {
    }; // class definition, semicolon is mandatory

    class C {
    } f(); // because otherwise it is a return type of a function.
} // no need for semicolon

namespace D = A; // semicolon is mandatory.

If these are not the cases you talked about, comment please.

Answer 2

No. Namespaces do not need to end with a semicolon though Bjarne wanted to do it I guess to reduce syntax related discrepancies with other C++ constructs. However I am not sure why it was not accepted.

"Silly typing errors will inevitably arise from the syntactic similarity of the namespace constructs to other C++ constructs. I propose we allow an optional semicolon after a global declaration to lessen the frustration. This would be a kind of ‘‘empty declaration’’ to match the empty statements."

All forward declarations of the class need to end with a semicolon. Can you give examples of where it is optional in C++?