Title
Undefined behavior for predefined macros
Status
open
Section
15.11 [cpp.predefined]
Submitter
US

Created on 2019-10-23.00:00:00 last changed 3 weeks ago

Messages

Date: 2023-01-15.00:00:00

Additional notes (January, 2023):

Forwarded to SG12 with paper issue 1412, by decision of the CWG and SG12 chairs.

Date: 2019-10-23.00:00:00

(From National Body comments US 148 and US 149 on the C++20 DIS.)

Subclause 15.11 [cpp.predefined] paragraph 4 specifies:

If any of the pre-defined macro names in this subclause, or the identifier defined, is the subject of a #define or a #undef preprocessing directive, the behavior is undefined.

Undefined behavior during lexing is not acceptable. This ought to be ill-formed.

History
Date User Action Args
2023-01-05 08:22:04adminsetmessages: + msg7115
2019-10-23 00:00:00admincreate