wcsrtombs(3) - NetBSD Manual Pages

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WCSRTOMBS(3)            NetBSD Library Functions Manual           WCSRTOMBS(3)


NAME

     wcsrtombs -- converts a wide-character string to a multibyte character
     string (restartable)


LIBRARY

     Standard C Library (libc, -lc)


SYNOPSIS

     #include <wchar.h>

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


DESCRIPTION

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

     ·   The conversion reaches a nul wide character.  In this case, the nul
         wide character is also converted.

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

     ·   The conversion encounters an invalid character.

     Each character 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 nul 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 nul wide character, wcsrtombs() places the state object pointed to by
     ps to an initial state after the conversion is taken place.

     The behaviour of 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 nul byte.  In this case, n is ignored.

     pwcs == NULL || *pwcs == NULL
                   Undefined (may cause 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 Standard C Library (libc,
                   -lc) never changes the internal state of wcsrtombs(), which
                   is initialized at startup time of the program.


RETURN VALUES

     wcsrtombs() returns:

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

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


ERRORS

     wcsrtombs() may cause an error in the following case:

     [EILSEQ]           pwcs points to a string containing an invalid wide
                        character.


SEE ALSO

     setlocale(3), wcrtomb(3), wcstombs(3)


STANDARDS

     The wcsrtombs() function conforms to ANSI X3.159-1989 (``ANSI C89'').
     The restrict qualifier is added at ISO/IEC 9899:1999 (``ISO C99'').

NetBSD 9.2                      August 8, 2006                      NetBSD 9.2