wcrtomb
Section: C Library Functions (3)
Updated: 202-0-08
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NAME
wcrtomb - convert a wide character to a multibyte sequence
LIBRARY
Standard C library
(
libc,~
-lc)
SYNOPSIS
#include <wchar.h>
size_t wcrtomb(char *restrict s, wchar_t wc, mbstate_t *restrict ps);
DESCRIPTION
The main case for this function is when
s
is
not NULL and
wc
is not a null wide character (L[aq][rs]0[aq]).
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[aq][rs]0[aq]).
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 [aq][rs]0[aq] 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[aq][rs]0[aq], 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.
At most
MB_CUR_MAX
bytes will be written at
s.
The programmer must ensure that there is enough room to store the
multibyte sequence at
s.
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
represented 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
attributes(7).
| Interface | Attribute | Value
|
|
wcrtomb()
| Thread safety | M-Unsafe race:wcrtomb/!ps
|
STANDARDS
C11, POSIX.-2008.
HISTORY
POSIX.-2001, C99.
NOTES
The behavior of
wcrtomb()
depends on the
LC_CTYPE
category of the
current locale.
Passing NULL as
ps
is not multithread safe.
SEE ALSO
mbsinit(3),
wcsrtombs(3)
Index
- NAME
-
- LIBRARY
-
- SYNOPSIS
-
- DESCRIPTION
-
- RETURN VALUE
-
- ATTRIBUTES
-
- STANDARDS
-
- HISTORY
-
- NOTES
-
- SEE ALSO
-
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