How can I "unuse" a namespace?

c++ namespaces c++builder
Roddy picture Roddy · Oct 3, 2008 · Viewed 40.6k times · Source

One of the vagaries of my development system (Codegear C++Builder) is that some of the auto-generated headers insist on having... 

using namespace xyzzy

...statements in them, which impact on my code when I least want or expect it.

Is there a way I can somehow cancel/override a previous "using" statement to avoid this.

Maybe...

unusing namespace xyzzy;

Answer

Head Geek picture Head Geek · Oct 3, 2008

Nope. But there's a potential solution: if you enclose your include directive in a namespace of its own, like this...

namespace codegear {
    #include "codegear_header.h"
} // namespace codegear

...then the effects of any using directives within that header are neutralized.

That might be problematic in some cases. That's why every C++ style guide strongly recommends not putting a "using namespace" directive in a header file.

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