07/11/10 12:43:08
>>224
さっきから実装依存だと言ってるのって、名前空間スコープに定義した const 変数の
話じゃないの？
クラスの static const なメンバ変数はクラス定義内では宣言しかされないので、
別途定義が必要。整数型に限って、宣言につけた初期値を持つ定数式として使える
という特別ルールがあるだけ。
C++ 2003 規格の 9.4.2 p2 より
> The declaration of a static data member in its class definition is not a definition and may be of an
> incomplete type other than cv-qualified void. The definition for a static data member shall appear in a
> namespace scope enclosing the member’s class definition.
同じく 9.4.2 p4
> If a static data member is of const integral or const enumeration type, its declaration in the class
> definition can specify a constant-initializer which shall be an integral constant expression (5.19). In that
> case, the member can appear in integral constant expressions. The member shall still be defined in a namespace
> scope if it is used in the program and the namespace scope definition shall not contain an initializer.