forward declaration of a class in another namespace

[dj]

How can I make a forward declaration of a class that is defined in some
other namespace? E.g.:

file1.h:

namespace A {
class A {...};
}

file2.h:

class A::A; //error: A is not a namespace
class B {
A* a;
};
The only way I found is to include file1.h in file2.h. But in that case
I don't need a forward declaration of A anymore, because I lose the
compilation "independence" anyway.

[Tom Smith]

dj wrote:

How can I make a forward declaration of a class that is defined in some
other namespace? E.g.:

Enclose the forward declaration in a "namespace NAME { }"; ie:

// begin code

namespace C
{
class A;
}

class B
{
C::A* PointerToUnknownClass;
};

int main()
{
return 0;
}

// end code

This compiles fine on my G++. Hope that helps.

Tom