WCSRTOMBS(3)               POSIX Programmer's Manual              WCSRTOMBS(3)



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

NAME
       wcsnrtombs, wcsrtombs -- convert a wide-character string to a character
       string (restartable)

SYNOPSIS
       #include <wchar.h>

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

DESCRIPTION
       For wcsrtombs(): The functionality described on this reference page is
       aligned with the ISO C standard. Any conflict between the requirements
       described here and the ISO C standard is unintentional. This volume of
       POSIX.1-2017 defers to the ISO C standard.

       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 wcsnrtombs() and wcsrtombs() functions need not be thread-safe if
       called with a NULL ps argument.

       The wcsnrtombs() function shall be equivalent to the wcsrtombs()
       function, except that the conversion is limited to the first nwc wide
       characters.

       The wcsrtombs() function shall not change the setting of errno if
       successful.

       The behavior of these functions shall be affected by the LC__CTYPE
       category of the current locale.

       The implementation shall behave as if no function defined in System
       Interfaces volume of POSIX.1-2017 calls these functions.

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, these
       functions shall store the value of the macro [EILSEQ] in errno and
       return (size_t)-1; the conversion state is undefined.  Otherwise, these
       functions shall return the number of bytes in the resulting character
       sequence, not including the terminating null (if any).

ERRORS
       These functions shall fail if:

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

       These functions may fail if:

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

       The following sections are informative.

EXAMPLES
       None.

APPLICATION USAGE
       None.

RATIONALE
       None.

FUTURE DIRECTIONS
       None.

SEE ALSO
       mbsinit(), wcrtomb()

       The Base Definitions volume of POSIX.1-2017, <wchar.h>

COPYRIGHT
       Portions of this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1-2017, Standard for Information Technology --
       Portable Operating System Interface (POSIX), The Open Group Base
       Specifications Issue 7, 2018 Edition, Copyright (C) 2018 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 .

       Any typographical or formatting errors that appear in this page are
       most likely to have been introduced during the conversion of the source
       files to man page format. To report such errors, see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .



IEEE/The Open Group                  2017                         WCSRTOMBS(3)
