https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114876
Bruno Haible <bruno at clisp dot org> changed:
What |Removed |Added
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CC| |bruno at clisp dot org
--- Comment #1 from Bruno Haible <bruno at clisp dot org> ---
What does *printf of %lc with a (wint_t) '\0' argument do?
Note that the published POSIX:2018 still has a wrong description: Its
description requires *printf to produce 0 characters.
This was wrong in ISO C as well. It has been corrected in ISO C 23 ยง 7.23.6.1,
in the meeting from 2023-06-20 to 2023-06-23. See
https://www.open-std.org/JTC1/sc22/wg14/www/docs/n3167.pdf section GB-141 page
23, 24. The decision ("option 1") is detailed in
https://www.open-std.org/JTC1/sc22/wg14/www/docs/n3148.doc row GB-141 page 34,
35:
"Option 1 (require a NUL) - change the text to:
If an l length modifier is present, the wint_t argument is converted
as if by a call to the wcrtomb function with a pointer to storage of
at least MB_CUR_MAX bytes, the wint_t argument converted to wchar_t,
and an initial shift state."
This description requires *printf to produce 1 NUL character.
Then, the Austin Group followed suit and, through
https://austingroupbugs.net/view.php?id=1647 , decided that POSIX will use the
same definition:
"If an l (ell) qualifier is present, the wint_t argument shall be converted
to a multi-byte sequence as if by a call to wcrtomb( ) with the wint_t
argument converted to wchar_t and an initial shift state, and the
resulting bytes written."
This aligns the POSIX behaviour with what glibc was doing all the time, namely
to produce 1 NUL character.
