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

2024-10-26

2402. When is the restriction to a single c-char in a Unicode literal enforced?

[Adopted at the November, 2020 meeting as part of paper P2029R4.]

According to 5.13.3 [lex.ccon] paragraphs 3-5, a Unicode character literal “containing multiple c-chars is ill-formed.” However, it is not clear in what phase of translation that restriction applies.

One possible resolution would be to add a note saying that the pp-token is formed according to the grammar and the restriction to a single c-char is checked in phase 7.