WCSRTOMBS(3)              OpenBSD Programmer's Manual             WCSRTOMBS(3)

NAME
     wcsrtombs - converts a wide character string to a multibyte character

SYNOPSIS
     #include <stdlib.h>

     size_t
     wcsrtombs(const char * restrict s, const wchar_t ** restrict pwcs,
             size_t n, mbstate_t * restrict ps);

DESCRIPTION
     The wcsrtombs() converts the null-terminated wide character string indi-
     rectly pointed to by pwcs to the corresponding multibyte character
     string, and store it to the array pointed to by s.  The conversion stops
     due to the following reasons:

     o   The conversion reaches a null wide character.  In this case, the null
         wide character is also converted.

     o   The wcsrtombs() has already stored n bytes to the array pointed to by
         s.

     o   The conversion encounters an invalid character.

     Each characters will be converted as if wcrtomb(3) is continuously
     called, except the internal state of wcrtomb(3) will not be affected.

     After conversion, if s is not a NULL pointer, the pointer object pointed
     to by pwcs is a NULL pointer (if the conversion is stopped due to reach-
     ing a null wide character) or the first byte of the character just after
     the last character converted.

     If s is not a null pointer and the conversion is stopped due to reaching
     a null wide character, the wcsrtombs() places the state object pointed to
     by ps to an initial state after the conversion is taken place.

     The behaviour of the wcsrtombs() is affected by the LC_CTYPE category of
     the current locale.

     These are the special cases:

     s == NULL     wcsrtombs() returns the number of bytes to store the whole
                   multibyte character string corresponding to the wide char-
                   acter string pointed to by pwcs, not including the termi-
                   nating null byte.  In this case, n is ignored.

     pwcs == NULL || *pwcs == NULL
                   Undefined (may causes the program to crash).

     ps == NULL    wcsrtombs() uses its own internal state object to keep the
                   conversion state, instead of ps mentioned in this manual
                   page.

                   Calling any other functions in libc never change the inter-
                   nal state of wcsrtombs(), that is initialized at startup
                   time of the program.

RETURN VALUES
     wcsrtombs() returns:

     0 or positive
                   Number of bytes stored to the array pointed to by s, except
                   for a null byte.  There is no cases that the value returned
                   is greater than n (unless s is a null pointer).  If the re-
                   turn value is equal to n, the string pointed to by s will
                   not be null-terminated.

     (size_t)-1    pwcs points to the string containing invalid wide charac-
                   ter.  The wcsrtombs() also sets errno to indicate the er-
                   ror.

ERRORS
     wcsrtombs() may cause an error in the following cases:

     [EILSEQ]      pwcs points to the string containing an invalid wide char-
                   acter.

SEE ALSO
     setlocale(3), wcrtomb(3), wcstombs(3)

STANDARDS
     The wcsrtombs() function conforms to ANSI X3.159-1989 (``ANSI C'').  The
     restrict qualifier is added at ISO/IEC 9899/AMD1:1995 (``ISO C99'').

OpenBSD 4.1                    February 4, 2002                              2
