tree 8ccbd0f43ab2b28714e692b9275e5afb14ce0298
parent e3f561cffc41110a1946c682256a17d42ceecf1d
author LIU Hao <lh_mouse@126.com> 1682606122 +0800
committer LIU Hao <lh_mouse@126.com> 1682608327 +0800

headers: Hide UTF-16 and UTF-32 functions from libmsvcrt

While these are standard C11 functions, Microsoft docs say they operate
on strings in UTF-8, instead of strings in the encoding determined by the
current locale. The MSVCRT `mbstate_t`, being an `int`, is too small for
implementations of these functions.

This commit ensures these functions are only declared for UCRT; when
targeting MSVCRT only the typedefs are available.

Reference: https://learn.microsoft.com/en-us/cpp/c-runtime-library/reference/c16rtomb-c32rtomb1?view=msvc-170
Signed-off-by: LIU Hao <lh_mouse@126.com>