максимальная длина многобайтового символа в текущей локали  (maximum length of a multibyte character in the current locale)
  
Имя (Name)
MB_CUR_MAX - maximum length of a multibyte character in the
       current locale
Синопсис (Synopsis)
#include <stdlib.h>
Описание (Description)
The MB_CUR_MAX macro defines an integer expression giving the
       maximum number of bytes needed to represent a single wide
       character in the current locale.  This value is locale dependent
       and therefore not a compile-time constant.
Возвращаемое значение (Return value)
An integer in the range [1, MB_LEN_MAX].  The value 1 denotes
       traditional 8-bit encoded characters.
Стандарты (Conforming to)
POSIX.1-2001, POSIX.1-2008, C99.
Смотри также (See also)
MB_LEN_MAX(3), mblen(3), mbstowcs(3), mbtowc(3), wcstombs(3),
       wctomb(3)