NAME

A call with a null mbchar pointer returns nonzero if the current locale requires shift states, zero otherwise; if shift states are required, the shift state is reset to the initial state.

RETURN VALUES

Otherwise, if mbchar is not a null pointer, mblen either returns 0 if mbchar represents the null wide character, or returns the number of bytes processed in mbchar, or returns -1 if no multibyte character could be recognized or converted. In this case, mblen ’s internal conversion state is undefined.

ERRORS