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

2022-07-01


630. Equality of narrow and wide character values in the basic character set

Section: 5.3  [lex.charset]     Status: CD2     Submitter: Tom Plum     Date: 21 April 2007

[Voted into WP at October, 2009 meeting.]

WG14 accepted DR 279 regarding the rule known colloquially as the L'x'=='x' rule. This change was made to C99 in TC2. The Austin Group subsequently opened DR 321 against TC2, observing that the change made in TC2 would invalidate existing conforming C code that relied on the L'x'=='x' rule.

DR 321 is now closed and will be included in the CD3 to C99. This change defines a new standard macro, which WG14 drafted as follows:

__STDC_MB_MIGHT_NEQ_WC__: The integer constant 1, intended to indicate that there might be some character x in the basic character set, such that 'x' need not be equal to L'x'.

WG14 requests that WG21 adopt this revision and this macro in C++0x.

Proposed resolution (July, 2009):

Add the following to 15.11 [cpp.predefined] paragraph 2:

__STDC_MB_MIGHT_NEQ_WC__
The integer constant 1, intended to indicate that, in the encoding for wchar_t, a member of the basic character set need not have a code value equal to its value when used as the lone character in an ordinary character literal.