referencing something from global namespace?

Question

This is really trivial but I'm getting an error I didn't expect.

I have some code which is inside of a namespace

the following is some pseudocode that represents the structure of my code:

namespace A {
    void init() {
        initialize_kitchen_sink();
    }
    #include "operations.h" // declares shake_and_bake()
    void foo() {            
        shake_and_bake();
    }
    void cleanup() {
        // do nothin' cuz i'm a slob
    }
}

error:

undefined reference to `A::shake_and_bake`

Answer 1

Turns out moving the #include outside the namespace will fix it.

As it was, the include would be in effect declaring all of the functions in operations.h inside the A namespace. Then it would search in vain for the implementations.

I figure instead of deleting my entire post i may as well leave it for that minute possibility that someone else may stumble upon a similar problem and be enlightened.

Answer 2

To answer precisely to your question, you can reference something from the global namespace by using :: as your first statement as in :

 void foo() {            
        ::shake_and_bake();
    }

Of course, your answer, for this special case is right though.