Question

This is a rather simple question more or less considering syntax semantics.

I’ve got a class inside a namespace, which uses a lot of classes out of another namespace:

namespace SomeNamespace
{
   class MyClass
   {
      //...

      //These types of namespace uses occur alot around here:
      void DoSomething(const anothernamespace::anotherclass &arg);
      //...
   }
}

This class is of course in its own .hpp file.

I would like to make everything inside the namespace “anothernamespace” available to the MyClass class, however, if I simply put it like this:

namespace SomeNamespace
{
   using namespace anothernamespace;
   class MyClass
   {
      //...

      //These types of namespace uses occur alot around here:
      void DoSomething(const anothernamespace::anotherclass &arg);
      //...
   }
}

Anyone who does

using namespace SomeNamespace;

Will automatically also use anothernamespace – which is what I want to avoid.

How do I achieve what I want?

Answer 1

This does what you want. Both namespaces are accessible to MyClass. using namespace is bad practice in headers though.

namespace SomeNamespace {
namespace other {
  using namespace anothernamespace;
  class MyClass {
  };
}}

namespace SomeNamepace {
  typedef other::MyClass MyClass;
}

You really should prefer specifying anothernamespace:: in your class declaration.