This is an unofficial snapshot of the ISO/IEC JTC1 SC22 WG21 Core Issues List revision 113d. See http://www.open-std.org/jtc1/sc22/wg21/ for the official list.

2024-03-20


2242. ODR violation with constant initialization possibly omitted

Section: 6.3  [basic.def.odr]     Status: C++23     Submitter: Hubert Tong     Date: 2016-03-05

P2720R0 comment US 5-033

[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 from issue 2123.)

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

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