WCRTOMB(3P) POSIX Programmer's Manual WCRTOMB(3P)PROLOG
This manual page is part of the POSIX Programmer's Manual. The Linux
implementation of this interface may differ (consult the corresponding
Linux manual page for details of Linux behavior), or the interface may
not be implemented on Linux.
NAMEwcrtomb — convert a wide-character code to a character (restartable)
SYNOPSIS
#include <wchar.h>
size_t wcrtomb(char *restrict s, wchar_t wc, mbstate_t *restrict ps);
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.1‐2008
defers to the ISO C standard.
If s is a null pointer, the wcrtomb() function shall be equivalent to
the call:
wcrtomb(buf, L'\0', ps)
where buf is an internal buffer.
If s is not a null pointer, the wcrtomb() function shall determine the
number of bytes needed to represent the character that corresponds to
the wide character given by wc (including any shift sequences), and
store the resulting bytes in the array whose first element is pointed
to by s. At most {MB_CUR_MAX} bytes are stored. If wc is a null wide
character, a null byte shall be stored, preceded by any shift sequence
needed to restore the initial shift state. The resulting state
described shall be the initial conversion state.
If ps is a null pointer, the wcrtomb() 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 POSIX.1‐2008 calls
wcrtomb().
The wcrtomb() function need not be thread-safe if called with a NULL ps
argument.
The behavior of this function shall be affected by the LC_CTYPE cate‐
gory of the current locale.
The wcrtomb() function shall not change the setting of errno if suc‐
cessful.
RETURN VALUE
The wcrtomb() function shall return the number of bytes stored in the
array object (including any shift sequences). When wc is not a valid
wide character, an encoding error shall occur. In this case, the func‐
tion shall store the value of the macro [EILSEQ] in errno and shall
return (size_t)−1; the conversion state shall be undefined.
ERRORS
The wcrtomb() function shall fail if:
EILSEQ An invalid wide-character code is detected.
The wcrtomb() function 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 ALSOmbsinit(), wcsrtombs()
The Base Definitions volume of POSIX.1‐2008, <wchar.h>
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 7, Copyright (C) 2013 by the Institute of Electri‐
cal and Electronics Engineers, Inc and The Open Group. (This is
POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) 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.unix.org/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.ker‐
nel.org/doc/man-pages/reporting_bugs.html .
IEEE/The Open Group 2013 WCRTOMB(3P)
