NAME

       wcsrtombs - convert a wide-character string to a character string (restartable)

SYNOPSIS

       #include <wchar.h>

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

DESCRIPTION

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

        * When a code is reached that does not correspond to a valid character

        * When the next character would exceed the limit of len total bytes to be stored  in  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 wcrtomb() 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  wide
       character)  or  the  address  just  past  the  last  wide character converted (if any). If
       conversion stopped due to reaching a terminating null wide character, the resulting  state
       described shall be the initial conversion state.

       If  ps  is  a  null pointer, the wcsrtombs() 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  shall
       behave as if no function defined in this volume of IEEE Std 1003.1-2001 calls wcsrtombs().

       If  the  application  uses  any  of  the  _POSIX_THREAD_SAFE_FUNCTIONS  or  _POSIX_THREADS
       functions, the application shall ensure that the wcsrtombs() 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

       If conversion stops because a code  is  reached  that  does  not  correspond  to  a  valid
       character,  an  encoding  error occurs. In this case, the wcsrtombs() function shall store
       the value of the macro [EILSEQ] in errno and return (size_t)-1; the  conversion  state  is
       undefined.  Otherwise,  it  shall  return  the  number of bytes in the resulting character
       sequence, not including the terminating null (if any).

ERRORS

       The wcsrtombs() function may fail if:

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

       EILSEQ A wide-character code does not correspond to a valid character.

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

       None.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       mbsinit() , wcrtomb() , 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, 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 .