Forward decleration of enumerations and typedefs in a NameSpace

[kasiyil]

Hello,
I have a compilation problem about namespaces:

I have a namespace X in which I declera a type definition:

In X.h file i write:

namespace X {
typedef unsigned int WindowHandle_t;
}

In a class which is in a different namespace ( Y ), I must use the type
definition I declared in namespace X.
MyClass.h file:

Y::MyClass {
....
private:
X::WindowHandle_t handle;
....
}

And the code doesn't compile. I should forward declare this handle type
definition but forward decleration is the same as writing the same
thing that I wrote in X.h file. When I write

In MyClass.h file :

namespace X {
typedef unsigned int WindowHandle_t;
}


Y::MyClass {
....
private:
X::WindowHandle_t handle;
....
}

The code compiles. But as I stated, I do not want to write same type
definition twice in a code. Do you have any suggestions?

Thanks...

 

[Ian Collins]

Hello,
I have a compilation problem about namespaces:

I have a namespace X in which I declera a type definition:

In X.h file i write:

namespace X {
typedef unsigned int WindowHandle_t;
}

In a class which is in a different namespace ( Y ), I must use the type
definition I declared in namespace X.
MyClass.h file:

Y::MyClass {
....
private:
X::WindowHandle_t handle;
....
}

And the code doesn't compile. I should forward declare this handle type
definition but forward decleration is the same as writing the same
thing that I wrote in X.h file. When I write

Have you included X.h?

 

[kasiyil]

I included it after MyClass.h. There is no way to include it before
MyClass.h .

 

[Jens Theisen]

I included it after MyClass.h. There is no way to include it before
MyClass.h .

Why is there no way?

You need to include it from within MyClass.h and before the definition
of MyClass, or move it to another header and do so with the new header.

Forward declaration has nothing to do with this. Even if you could
forward declare a typedef, which unfortunately you don't, it wouldn't
help you because

1. You're returning the type by value so it has to be complete anyway
2. For the sake of clean code you will probably want to put the forward
delcaration in a header anyway.

Jens