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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 continues 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 completely 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 conversion 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>


       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, Copyright (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.opengroup.org/unix/online.html .