This is an unofficial snapshot of the ISO/IEC JTC1 SC22 WG21 Core Issues List revision 108i. See http://www.open-std.org/jtc1/sc22/wg21/ for the official list.

2022-07-16


1861. Values of a bit-field

Section: 11.4.10  [class.bit]     Status: CD4     Submitter: Hubert Tong     Date: 2014-02-13

[Adopted at the June, 2016 meeting.]

The resolution of issue 1816 left many aspects of bit-fields unspecified, including whether a signed bit field has a sign bit and the meaning of the bit-field width. Also, the requirement in 6.8.2 [basic.fundamental] paragraph 1 that

For narrow character types, all bits of the object representation participate in the value representation.

should not apply to oversize character-typed bit-fields.

Notes from the June, 2014 meeting:

CWG decided to address only the issue of oversized bit-fields of narrow character types at this time, splitting off the more general questions regarding bit-fields to issue 1943.

Proposed resolution (April, 2016):

Change 6.8.2 [basic.fundamental] paragraph 1 as follows:

...For narrow character types, all bits of the object representation participate in the value representation. [Note: A bit-field of narrow character type whose length is larger than the number of bits in the object representation of that type has padding bits; see 11.4.10 [class.bit]. —end note] For unsigned narrow character types, each possible bit pattern of the value representation represents a distinct number...