MBSRTOWCS(3P)                                       POSIX Programmer's Manual                                      MBSRTOWCS(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
       mbsrtowcs - convert a character string to a wide-character string (restartable)

SYNOPSIS
       #include <wchar.h>

       size_t mbsrtowcs(wchar_t *restrict dst, const char **restrict src,
              size_t len, mbstate_t *restrict ps);


DESCRIPTION
       The  mbsrtowcs()  function  shall  convert  a  sequence of characters, beginning in the conversion state described by the
       object pointed to by ps, from the array indirectly pointed to by src into a sequence of corresponding wide characters. If
       dst is not a null pointer, the converted characters shall be stored into the array pointed to by dst.  Conversion contin-
       ues up to and including a terminating null character, which shall also be stored. Conversion shall stop early  in  either
       of the following cases:

        * A sequence of bytes is encountered that does not form a valid character.

        * len codes have been stored into the array pointed to by dst (and dst is not a null pointer).

       Each conversion shall take place as if by a call to the mbrtowc() function.

       If dst is not a null pointer, the pointer object pointed to by src shall be assigned either a null pointer (if conversion
       stopped due to reaching a terminating null character) or the address just past the last character converted (if any).  If
       conversion  stopped  due  to reaching a terminating null character, and if dst is not a null pointer, the resulting state
       described shall be the initial conversion state.

       If ps is a null pointer, the mbsrtowcs() function shall use its own internal mbstate_t object, which  is  initialized  at
       program  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 behaves as  if  no
       function defined in this volume of IEEE Std 1003.1-2001 calls mbsrtowcs().

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

RETURN VALUE
       If  the  input conversion encounters a sequence of bytes that do not form a valid character, an encoding error occurs. In
       this case, the mbsrtowcs() function stores the value of the macro [EILSEQ] in errno and shall return (size_t)-1; the con-
       version state is undefined. Otherwise, it shall return the number of characters successfully converted, not including the
       terminating null (if any).

ERRORS
       The mbsrtowcs() function may fail if:

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

       EILSEQ Invalid character sequence is detected.


       The following sections are informative.

EXAMPLES
       None.

APPLICATION USAGE
       None.

RATIONALE
       None.

FUTURE DIRECTIONS
       None.

SEE ALSO
       mbsinit(), mbrtowc(), 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                                                 MBSRTOWCS(3P)