WCRTOMB(3) Linux Programmer's Manual WCRTOMB(3)
NAME
wcrtomb - convert a wide character to a multibyte sequence
SYNOPSIS
#include <wchar.h>
size_t wcrtomb(char *s, wchar_t wc, mbstate_t *ps);
DESCRIPTION
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 con-
verts 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 represen-
tation, 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.
RETURN VALUE
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 rep-
resented as a multibyte sequence (according to the current locale),
(size_t) -1 is returned, and errno set to EILSEQ.
ATTRIBUTES
For an explanation of the terms used in this section, see at-
tributes(7).
+----------+---------------+----------------------------+
|Interface | Attribute | Value |
+----------+---------------+----------------------------+
|wcrtomb() | Thread safety | MT-Unsafe race:wcrtomb/!ps |
+----------+---------------+----------------------------+
CONFORMING TO
POSIX.1-2001, POSIX.1-2008, C99.
NOTES
The behavior of wcrtomb() depends on the LC_CTYPE category of the cur-
rent locale.
Passing NULL as ps is not multithread safe.
SEE ALSO
mbsinit(3), wcsrtombs(3)
COLOPHON
This page is part of release 5.07 of the Linux man-pages project. A
description of the project, information about reporting bugs, and the
latest version of this page, can be found at
https://www.kernel.org/doc/man-pages/.
GNU 2019-03-06 WCRTOMB(3)