SYNOPSIS

     #include <stdlib.h>

     int
     mbtowc(wchar_t * restrict wcharp, const char * restrict mbchar,
         size_t nbytes);

     #include <xlocale.h>

     int
     mbtowc_l(wchar_t * restrict wcharp, const char * restrict mbchar,
         size_t nbytes, locale_t loc);

DESCRIPTION

     The mbtowc() function converts a multibyte character mbchar into a wide
     character according to the current conversion state, and stores the
     result in the object pointed to by wcharp.  Up to nbytes bytes are exam-
     ined.

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

     While the mbtowc() function uses the current locale, the mbtowc_l() func-
     tion may be passed a locale directly. See xlocale(3) for more informa-
     tion.

RETURN VALUES

     If mbchar is NULL, the mbtowc() function returns nonzero if shift states
     are supported, zero otherwise.

     Otherwise, if mbchar is not a null pointer, mbtowc() 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, mbtowc()'s internal conversion
     state is undefined.

ERRORS

     The mbtowc() function will fail if:

     [EILSEQ]           An invalid multibyte sequence was detected.

     [EINVAL]           The internal conversion state is invalid.

SEE ALSO

     btowc(3), mblen(3), mbrtowc(3), mbstowcs(3), multibyte(3), wctomb(3),
     xlocale(3)

STANDARDS

     The mbtowc() function conforms to ISO/IEC 9899:1999 (``ISO C99'').