Friday, February 15, 2008

c++: namespace alias

Recently found interesting feature in c++: alias to namespace.
namespace A
{
    int A = 5;
};

namespace B = A;
I wonder what is it for ... ?

3 comments:

  1. ChebaFebruary 15, 2008 at 4:48 PM

    One more power feature to be misused?

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  2. Ni@mFebruary 15, 2008 at 11:12 PM

    Not actually.
    You may rename namespace if you have namespace with a very long name:
    namespace verylongnameofthenamecpace
    {
    }
    namespace A = verylongnameofthenamecpace;
    or simplify usage of nested:
    namespace A
    {
    namespace A
    {
    namespace A
    {
    }
    }
    }
    namespace B = A::A::A;
    Also some rare problems are faced here: http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2003/n1526.txt

    ReplyDelete
  3. BobMay 13, 2009 at 6:30 AM

    As Ni@m mentioned, it's useful when dealing with namespaces with long names, or that are deeply nested.

    You'll appreciate namespace aliasing when you spend some time with the boost libraries.

    I've written a bit more about it's utility here: http://www.juicydata.com/CppNamespaceAlias.

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