WCSTOMBS(3)                POSIX Programmer's Manual               WCSTOMBS(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
       wcstombs -- convert a wide-character string to a character string

SYNOPSIS
       #include <stdlib.h>

       size_t wcstombs(char *restrict _s, const wchar_t *restrict pwcs,
           size_t _n);

DESCRIPTION
       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 wcstombs() function shall convert the sequence of wide-character
       codes that are in the array pointed to by pwcs into a sequence of
       characters that begins in the initial shift state and store these
       characters into the array pointed to by _s, stopping if a character
       would exceed the limit of _n total bytes or if a null byte is stored.
       Each wide-character code shall be converted as if by a call to
       wctomb(), except that the shift state of wctomb() shall not be
       affected.

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

       No more than _n bytes shall be modified in the array pointed to by _s.
       If copying takes place between objects that overlap, the behavior is
       undefined.  If _s is a null pointer, wcstombs() shall return the length
       required to convert the entire array regardless of the value of _n, but
       no values are stored.

RETURN VALUE
       If a wide-character code is encountered that does not correspond to a
       valid character (of one or more bytes each), wcstombs() shall return
       (size_t)-1. Otherwise, wcstombs() shall return the number of bytes
       stored in the character array, not including any terminating null byte.
       The array shall not be null-terminated if the value returned is _n.

ERRORS
       The wcstombs() function shall fail if:

       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
       mblen(), mbtowc(), mbstowcs(), wctomb()

       The Base Definitions volume of POSIX.1-2017, <stdlib.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                          WCSTOMBS(3)
