How do you import an enum into a different namespace in C++?

Question

I have an enum in a namespace and I'd like to use it as if it were in a different namespace. Intuitively, I figured I could use 'using' or 'typedef' to accomplish this, but neither actually work. Code snippet to prove it, tested on GCC and Sun CC:

namespace foo {  enum bar {     A };  }  namespace buzz { // Which of these two methods I use doesn't matter, // the results are the same. using foo::bar; //typedef foo::bar bar; }  int main() {     foo::bar f; // works     foo::bar g = foo::A; // works      buzz::bar x; // works     //buzz::bar y = buzz::A; // doesn't work     buzz::bar z = foo::A; } 

The problem is that the enum itself is imported but none of its elements. Unfortunately, I can't change the original enum to be encased in an extra dummy namespace or class without breaking lots of other existing code. The best solution I can think of is to manually reproduce the enum:

namespace buzz { enum bar {     A = foo::A }; } 

But it violates the DRY principle. Is there a better way?

Answer 1

Wrap the existing namespace in a nested namespace which you then "use" in the original namespace.

namespace foo {     namespace bar_wrapper {         enum bar {             A         };     }     using namespace bar_wrapper; }  namespace buzz {     using namespace foo::bar_wrapper; }