mbrtowc (GNU Gnulib)

Gnulib module: mbrtowc

Portability problems fixed by Gnulib:

This function is missing on some platforms: Minix 3.1.8, HP-UX 11.00, mingw.
In the C or POSIX locales, this function can return (size_t) -1 and set errno to EILSEQ: glibc 2.35.
This function returns 0 instead of (size_t) -2 when the input is empty: glibc 2.19, MSVC 14, Android 11.
This function returns (size_t) -1 instead of (size_t) -2 when the input is empty: AIX 7.2.
This function does not put the state into non-initial state when parsing an incomplete multibyte character on some platforms: AIX 7.2.
This function stores a wide character when parsing an incomplete multibyte character on some platforms: MSVC 14.
This function returns the total number of bytes that make up the multibyte character, not the number of bytes that were needed to complete the multibyte character, on some platforms: HP-UX 11.11, Solaris 11 2010-11, mingw, MSVC 14.
This function may not return 0 when parsing the NUL character on some platforms: Solaris 9.

Portability problems not fixed by Gnulib:

In UTF-8 locales, this function may return wide characters up to 0x7FFFFFFF (that is, beyond 0x0010FFFF) on some platforms: glibc 2.34.
On Windows and 32-bit AIX platforms, wchar_t is a 16-bit type and therefore cannot accommodate all Unicode characters. However, the ISO C11 function mbrtoc32, provided by Gnulib module mbrtoc32, operates on 32-bit wide characters and therefore does not have this limitation.