Creating a namespace alias (C++ only)
An alternate name can be used in order to refer to a specific
namespace identifier.
namespace INTERNATIONAL_BUSINESS_MACHINES {
void f();
}
namespace IBM = INTERNATIONAL_BUSINESS_MACHINES;
In this example, the IBM identifier is an alias for INTERNATIONAL_BUSINESS_MACHINES. This is useful for referring to long namespace identifiers.
If a namespace name or alias is declared as the name of any other entity in the same declarative region, a compile-time error will result. Also, if a namespace name defined at global scope is declared as the name of any other entity in any global scope of the program, a compile-time error will result.