c++objective-cclassnamespacesforward-declaration

Forward declaration of a namespaced C++ class in in Objective C

Is it possible to do forward declaration of a C++ class, which is inside a namespace, in an Objective C header file?

C++ class to forward declare in Objective C:

namespace name
{
    class Clazz
    {

    };
}

I know I can if the C++ class is not in a namespace. Taken from http://www.zedkep.com/blog/index.php?/archives/247-Forward-declaring-C++-classes-in-Objective-C.html

Any thoughts?
Thanks guys!

Solution

  • You just declare it as usual, and wrap it in the C++ #ifdef check when the header is also included in C and/or ObjC translations:

    #ifdef __cplusplus
namespace name {
class Clazz;
} // << name
#endif

    For obvious reasons, you cannot use name::Clazz in a C or ObjC translation, so this works out perfectly. You either need the forward declaration in the C++ translation, or it does not need to be visible to C or ObjC.