freebsd man page for mbrtowc

MBRTOWC(3)						   BSD Library Functions Manual 						MBRTOWC(3)

NAME
     mbrtowc, mbrtoc16, mbrtoc32 -- convert a character to a wide-character code (restartable)

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <wchar.h>

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

     #include <uchar.h>

     size_t
     mbrtoc16(char16_t * restrict pc, const char * restrict s, size_t n, mbstate_t * restrict ps);

     size_t
     mbrtoc32(char32_t * restrict pc, const char * restrict s, size_t n, mbstate_t * restrict ps);

DESCRIPTION
     The mbrtowc(), mbrtoc16() and mbrtoc32() functions inspect at most n bytes pointed to by s to determine the number of bytes needed to com-
     plete the next multibyte character.  If a character can be completed, and pc is not NULL, the wide character which is represented by s is
     stored in the wchar_t, char16_t or char32_t it points to.

     If s is NULL, these functions behave as if pc 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, these functions use an internal, static mbstate_t
     object, which is initialized to the initial conversion state at program startup.

     As a single char16_t is not large enough to represent certain multibyte characters, the mbrtoc16() function may need to be invoked multiple
     times to convert a single multibyte character sequence.

RETURN VALUES
     The mbrtowc(), mbrtoc16() and mbrtoc32() functions return:

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

     >0      The next n or fewer bytes represent a valid character, these functions return the number of bytes used to complete the multibyte
	     character.

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

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

     The mbrtoc16() function also returns:

     (size_t)-3
	     The next character resulting from a previous call has been stored.  No bytes from the input have been consumed.

ERRORS
     The mbrtowc(), mbrtoc16() and mbrtoc32() functions will fail if:

     [EILSEQ]		An invalid multibyte sequence was detected.

     [EINVAL]		The conversion state is invalid.

SEE ALSO
     mbtowc(3), multibyte(3), setlocale(3), wcrtomb(3)

STANDARDS
     The mbrtowc(), mbrtoc16() and mbrtoc32() functions conform to ISO/IEC 9899:2011 (``ISO C11'').

BSD
								   May 21, 2013 							       BSD