This is an unofficial snapshot of the ISO/IEC JTC1 SC22 WG21 Core Issues List revision 116a. See http://www.open-std.org/jtc1/sc22/wg21/ for the official list.

2024-12-19

2206. Composite type of object and function pointers

[Adopted at the February/March, 2017 meeting.]

Consider an example like

  void *p;
  void (*pf)();
  auto x = true ? p : pf;

The rules in Clause 7 [expr] paragraph 13 say that the composite type between a void* and a function pointer type is void*. This is surprising, since a function pointer type cannot be implicitly converted to void*.

Proposed resolution (January, 2017):

Change Clause 7 [expr] bullet 14.5 as follows:

The cv-combined type of two types T1 and T2 is a type T3 similar to T1 whose cv-qualification signature (7.3.6 [conv.qual]) is:

• ...

• if T1 or T2 is “pointer to cv1 void” and the other type is “pointer to cv2 T”, where T is an object type or void, “pointer to cv12 void”, where cv12 is the union of cv1 and cv2;

• ...