wcrtomb - convert a wide character to a multibyte sequence
#include <wchar.h>
size_t wcrtomb(char *s, wchar_t wc, mbstate_t *ps);
The main case for this function is when
s is not NULL and
wc is
not a null wide character (L'\0'). In this case, the
wcrtomb() function
converts the wide character
wc to its multibyte representation and
stores it at the beginning of the character array pointed to by
s. It
updates the shift state
*ps, and returns the length of said multibyte
representation, that is, the number of bytes written at
s.
A different case is when
s is not NULL, but
wc is a null wide
character (L'\0'). In this case, the
wcrtomb() function stores at the
character array pointed to by
s the shift sequence needed to bring
*ps back to the initial state, followed by a '\0' byte. It updates the
shift state
*ps (i.e., brings it into the initial state), and returns
the length of the shift sequence plus one, that is, the number of bytes
written at
s.
A third case is when
s is NULL. In this case,
wc is ignored, and
the function effectively returns
wcrtomb(buf, L'\0', ps)
where
buf is an internal anonymous buffer.
In all of the above cases, if
ps is NULL, a static anonymous state known
only to the
wcrtomb() function is used instead.
The
wcrtomb() function returns the number of bytes that have been or
would have been written to the byte array at
s. If
wc can not be
represented as a multibyte sequence (according to the current locale),
(size_t) -1 is returned, and
errno set to
EILSEQ.
For an explanation of the terms used in this section, see
attributes(7).
| Interface |
Attribute |
Value |
| wcrtomb () |
Thread safety |
MT-Unsafe race:wcrtomb/!ps |
POSIX.1-2001, POSIX.1-2008, C99.
The behavior of
wcrtomb() depends on the
LC_CTYPE category of the
current locale.
Passing NULL as
ps is not multithread safe.
mbsinit(3),
wcsrtombs(3)