Standard C Library (libc, -lc)

SYNOPSIS

     #include <wchar.h>

     size_t
     mbrtowc(wchar_t * restrict pwc, const char * restrict s, size_t n,
         mbstate_t * restrict ps);

     #include <xlocale.h>

     size_t
     mbrtowc_l(wchar_t * restrict pwc, const char * restrict s, size_t n,
         mbstate_t * restrict ps, locale_t loc);

DESCRIPTION

     The mbrtowc() function inspects at most n bytes pointed to by s to deter-
     mine the number of bytes needed to complete the next multibyte character.
     If a character can be completed, and pwc is not NULL, the wide character
     which is represented by s is stored in the wchar_t it points to.

     If s is NULL, mbrtowc() behaves as if pwc was NULL, s was an empty string
     ("") and n was 1.

     The mbstate_t argument, ps, is used to keep track of the shift state.  If
     it is NULL, mbrtowc() uses an internal, static mbstate_t object, which is
     initialized to the initial conversion state at program startup.

     While the mbrtowc() function uses the current locale, the mbrtowc_l()
     function may be passed a locale directly. See xlocale(3) for more infor-
     mation.

RETURN VALUES

     The mbrtowc() functions returns:

     0       The next n or fewer bytes represent the null wide character
             (L'\0').

     >0      The next n or fewer bytes represent a valid character, mbrtowc()
             returns the number of bytes used to complete the multibyte char-
             acter.

     (size_t)-2
             The next n contribute to, but do not complete, a valid multibyte
             character sequence, and all n bytes have been processed.

     (size_t)-1
             An encoding error has occurred.  The next n or fewer bytes do not
             contribute to a valid multibyte character.

ERRORS

     The mbrtowc() function will fail if: