This is an unofficial snapshot of the ISO/IEC JTC1 SC22 WG21 Core Issues List revision 115e. See http://www.open-std.org/jtc1/sc22/wg21/ for the official list.

2024-11-11

2819. Cast from null pointer value in a constant expression

[Accepted at the June, 2024 meeting.]

Subclause 7.7 [expr.const] bullet 5.14 was amended by P2738R1 to support certain casts from void* to object pointer types. The bullet specifies:

• ...
• a conversion from a prvalue P of type “pointer to cv void” to a pointer-to-object type T unless P points to an object whose type is similar to T;
• ...

This wording does not, but should, support null pointer values. The implementation burden is negligible.

Proposed resolution (approved by CWG 2023-12-01):

Change in 7.7 [expr.const] bullet 5.14 as follows:

• ...
• a conversion from a prvalue P of type “pointer to cv void” to a pointer-to-object type T unless P is a null pointer value or points to an object whose type is similar to T;
• ...

CWG 2023-12-01

CWG seeks approval from EWG for the design direction. See paper issue 1698.

EWG 2024-03-18

EWG approves.

CWG 2024-04-19

This issue is not a DR.