Effective C + +-----clause 25: Consider writing a swap function that does not throw an exception

When Std::swap is inefficient for your type, provide a swap member function and make sure that the function does not throw an exception.

If you provide a member swap, you should also provide a non-member swap to invoke the former. For class (not templates), also special Std::swap.

You should use the using declaration for Std::swap when you call swap, and then call swap without any namespace qualification adornments.

STD templates for "User Defined type" is good, but don't try to add something new to STD in Std.

Effective C + +-----clause 25: Consider writing a swap function that does not throw an exception