mbrlen
======

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

Gnulib module: mbrlen

Portability problems fixed by Gnulib:

  * This function is missing on some platforms: Minix 3.1.8, HP-UX 11.00, IRIX 6.5, 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.

  * This function returns (size_t) -1 instead of (size_t) -2 when the input is empty: AIX 5.1.

  * This function does not put the state into non-initial state when parsing an incomplete multibyte character on some platforms: AIX 5.1.

  * 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.

  * This function may not return 0 when parsing the NUL character on some platforms: Solaris 9.

Portability problems not fixed by Gnulib: