NAME
wcrtomb - convert a wide-character code to a character (restartable)
SYNOPSIS
#include <stdio.h>
size_t wcrtomb(char *restrict s, wchar_t wc, mbstate_t *restrict ps);
DESCRIPTION
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 IEEE Std 1003.1-2001
calls wcrtomb().
If the application uses any of the _POSIX_THREAD_SAFE_FUNCTIONS or
_POSIX_THREADS functions, the application shall ensure that the
wcrtomb() 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
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
function 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 may fail if:
EINVAL ps points to an object that contains an invalid conversion
state.
EILSEQ Invalid wide-character code is detected.
The following sections are informative.
EXAMPLES
None.
APPLICATION USAGE
None.
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSO
mbsinit() , 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 .