Description

   The wctomb function converts the wide character specified by
   wchar to its multibyte character representation. If s is NULL,
   then 0 is returned. Otherwise, the number of bytes comprising the
   multibyte character is returned. At most, MB_CUR_MAX bytes are
   stored in the array object pointed to by s.

   This function is affected by the LC_CTYPE category of the
   program's current locale.