Maximum length of any multibyte character in any locale. Locale-writers should change this as necessary.
Minimum and maximum values a `char' can hold. The sign of "char" is probably dictated by a command-line switch to your compiler. MSVC will define _CHAR_UNSIGNED if the /J option is used. GCC uses --unsigned-char (and friends) to override the default for the target processor and defines a symbol __CHAR_UNSIGNED__ if appropriate.