btowc
=====

POSIX specification:
 https://pubs.opengroup.org/onlinepubs/9699919799/functions/btowc.html

Gnulib module: btowc

Portability problems fixed by Gnulib:

  * This function is missing on some platforms: Minix 3.1.8, HP-UX 11.00, mingw.

  * This function returns WEOF for a NUL argument on some platforms: Cygwin 1.7.2.

  * This function does not return WEOF for an EOF argument on some platforms: IRIX 6.5.

  * In the C or POSIX locales, this function is not consistent with Gnulib's mbrtowc and can return WEOF: glibc 2.35, MirOS BSD #10.

  * In the C or POSIX locales, this function is not consistent with mbrtowc on some platforms: mingw.

Portability problems not fixed by Gnulib:

  * On Windows and 32-bit AIX platforms, wchar_t is a 16-bit type and therefore cannot accommodate all Unicode characters. However, the Gnulib function btoc32, provided by Gnulib module btoc32, operates on 32-bit wide characters and therefore does not have this limitation.