WCRTOMB(3P)                                         POSIX Programmer's Manual                                        WCRTOMB(3P)



PROLOG
       This  manual  page is part of the POSIX Programmer's Manual.  The Linux implementation of this interface may differ (con-
       sult the corresponding Linux manual page for details of Linux behavior), or the  interface  may  not  be  implemented  on
       Linux.

NAME
       wcrtomb - convert a wide-character code to a character (restartable)

SYNOPSIS
       #include <stdio.h>

       size_t wcrtomb(char *restrict s, wchar_t wc, mbstate_t *restrict ps);


DESCRIPTION
       If s is a null pointer, the wcrtomb() function shall be equivalent to the call:


              wcrtomb(buf, L'\0', ps)

       where buf is an internal buffer.

       If  s is not a null pointer, the wcrtomb() function shall determine the number of bytes needed to represent the character
       that corresponds to the wide character given by wc (including any shift sequences), and store the resulting bytes in  the
       array  whose  first  element is pointed to by s. At most {MB_CUR_MAX} bytes are stored. If wc is a null wide character, a
       null byte shall be stored, preceded by any shift sequence needed to restore the initial shift state. The resulting  state
       described shall be the initial conversion state.

       If ps is a null pointer, the wcrtomb() function shall use its own internal mbstate_t object, which is initialized at pro-
       gram start-up to the initial conversion state. Otherwise, the mbstate_t object pointed to by ps shall  be  used  to  com-
       pletely describe the current conversion state of the associated character sequence. The implementation shall behave as if
       no function defined in this volume of IEEE Std 1003.1-2001 calls wcrtomb().

       If the application uses any of the _POSIX_THREAD_SAFE_FUNCTIONS or _POSIX_THREADS functions, the application shall ensure
       that the wcrtomb() function is called with a non-NULL ps argument.

       The behavior of this function shall be affected by the LC_CTYPE category of the current locale.

RETURN VALUE
       The  wcrtomb() function shall return the number of bytes stored in the array object (including any shift sequences). When
       wc is not a valid wide character, an encoding error shall occur.  In this case, the function shall store the value of the
       macro [EILSEQ] in errno and shall return (size_t)-1; the conversion state shall be undefined.

ERRORS
       The wcrtomb() function may fail if:

       EINVAL ps points to an object that contains an invalid conversion state.

       EILSEQ Invalid wide-character code is detected.


       The following sections are informative.

EXAMPLES
       None.

APPLICATION USAGE
       None.

RATIONALE
       None.

FUTURE DIRECTIONS
       None.

SEE ALSO
       mbsinit(), the Base Definitions volume of IEEE Std 1003.1-2001, <wchar.h>

COPYRIGHT
       Portions  of  this  text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for
       Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6,  Copy-
       right (C) 2001-2003 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any
       discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open  Group
       Standard   is   the   referee   document.   The   original   Standard   can   be   obtained  online  at  http://www.open-
       group.org/unix/online.html .



IEEE/The Open Group                                           2003                                                   WCRTOMB(3P)