Multibyte character string termination

Some APIs that use ITLocale assume that character strings are terminated with a null character, while others assume that a string consists of a pointer and length indicating the number of bytes in the string. ITLocale methods can be used in both cases.

The actual argument names might vary.

If nbytes is the value ITLocale::ScanToNul, the method treats s as a null-terminated string. Otherwise, the method assumes s contains nbytes bytes.

The terminator of a null-terminated string is a single byte whose value is 0. Multibyte character strings that are not null-terminated might contain null characters, but these characters do not indicate the end of the string.