Question

The title basically says it all, i wonder when static members of a c++ class are initialized and when they go out of scope.

I need this for the following problem. I have many objects of a class Foo and each object needs access to a resource, encapsulated by another class Bar. Synchronization is not an issue, so i want all objects to share the same Bar instance.

I’m using a simple managed pointer for reference counting.

Can i do the following:

class Foo {
private:
    static managed_pointer<Bar> staticBar;
public:
    Foo() {
        if(!staticBar)
            staticBar = new Bar;
    }
    /*
     * use staticBar in various non-static member functions
     */
};

managed_pointer<Bar> Foo::staticBar = NULL;

the managed_pointer staticBar should delete the Bar object as soon as it goes out of scope – but when does this happen? when the last instance of Foo is destructed? on application exit?

Thanks for your advice!

Answer 1

statics and globals are initialized right before the program starts (before main is called, the program actually starts before that) and go out of scope after main exits.

Exceptions – local statics (static variables declared inside functions) and unused template class staticmembers.

It has nothing to do with the number of instances.