Chapter 16 Namespaces

1the names N1.N2.A, R1.N2.A, and R2.A are equivalent and all refer to the class whose fully qualified

2name is N1.N2.A. end example]

3Although each part of a partial type (§17.1.4) is declared within the same namespace, the parts are typically

4written within different namespace declarations. Thus, different extern alias directives and using

5directives can be present for each part. When interpreting simple names (§14.5.2) within one part, only the

6extern alias directives and using directives of the namespace bodies and compilation unit enclosing that

7part are considered. This may result in the same identifier having different meanings in different parts.

8[Example:

9namespace N

10{

15}

16}

17namespace N

18{

23}

24}

25end example]

2616.4.2 Using namespace directives

27A using-namespace-directive imports the types contained in a namespace into the immediately enclosing

28compilation unit or namespace body, enabling the identifier of each type to be used without qualification.

29using-namespace-directive:

30using namespace-name ;

31Within member declarations in a compilation unit or namespace body that contains a using-namespace-

32directive, the types contained in the given namespace can be referenced directly. [Example:

33namespace N1.N2

34{

35class A {}

36}

37namespace N3

38{

40class B: A {}

41}

42Above, within member declarations in the N3 namespace, the type members of N1.N2 are directly

43available, and thus class N3.B derives from class N1.N2.A. end example]

44A using-namespace-directive imports the types contained in the given namespace, but specifically does not

45import nested namespaces. [Example: In the following code

46namespace N1.N2

47{

48class A {}

49}

50namespace N3

51{

249