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>

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 .