Movatterモバイル変換

This is an unofficial snapshot of the ISO/IEC JTC1 SC22 WG21 Core Issues List revision 119a. See http://www.open-std.org/jtc1/sc22/wg21/ for the official list.

2025-12-20

2242. ODR violation with constant initialization possibly omitted

[Accepted as a DR at the November, 2022 meeting.]

Consider the following example:

  // tu1.cpp  extern const int a = 1;  inline auto f() {    static const int b = a;    struct A { auto operator()() { return &b; } } a;    return a;  }  // tu2.cpp  extern const int a;  inline auto f() {    static const int b = a;    struct A { auto operator()() { return &b; } } a;    return a;  }  int main() {    return *decltype(f())()();  }

Here,b may or may not have constant initialization.This example should be an ODR violation.

(Split off fromissue 2123.)

Proposed resolution (approved by CWG 2022-11-11):

Insert after 6.3 [basic.def.odr] bullet 14.7 as follows:

• ...
• In each such definition, corresponding entities shallhave the same language linkage.
• In each such definition, const objects with static or threadstorage duration shall be constant-initialized if the object isconstant-initialized in any such definition.
• ...