wcsrtombs - convert a wide-character string to a multibyte string
Standard C library (
libc,
-lc)
#include <wchar.h>
size_t wcsrtombs(char dest[restrict .len], const wchar_t **restrict src,
size_t len, mbstate_t *restrict ps);
If
dest is not NULL, the
wcsrtombs() function converts the
wide-character string
*src to a multibyte string starting at
dest. At most
len bytes are written to
dest. The shift
state
*ps is updated. The conversion is effectively performed by
repeatedly calling
wcrtomb(dest, *src, ps), as long as this call
succeeds, and then incrementing
dest by the number of bytes written and
*src by one. The conversion can stop for three reasons:
- •
- A wide character has been encountered that can not be
represented as a multibyte sequence (according to the current locale). In
this case, *src is left pointing to the invalid wide character,
(size_t) -1 is returned, and errno is set to
EILSEQ.
- •
- The length limit forces a stop. In this case, *src
is left pointing to the next wide character to be converted, and the
number of bytes written to dest is returned.
- •
- The wide-character string has been completely converted,
including the terminating null wide character (L'\0'), which has the side
effect of bringing back *ps to the initial state. In this case,
*src is set to NULL, and the number of bytes written to
dest, excluding the terminating null byte ('\0'), is returned.
If
dest is NULL,
len is ignored, and the conversion proceeds as
above, except that the converted bytes are not written out to memory, and that
no length limit exists.
In both of the above cases, if
ps is NULL, a static anonymous state known
only to the
wcsrtombs() function is used instead.
The programmer must ensure that there is room for at least
len bytes at
dest.
The
wcsrtombs() function returns the number of bytes that make up the
converted part of multibyte sequence, not including the terminating null byte.
If a wide character was encountered which could not be converted,
(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 |
wcsrtombs () |
Thread safety |
MT-Unsafe race:wcsrtombs/!ps |
POSIX.1-2001, POSIX.1-2008, C99.
The behavior of
wcsrtombs() depends on the
LC_CTYPE category of
the current locale.
Passing NULL as
ps is not multithread safe.
iconv(3),
mbsinit(3),
wcrtomb(3),
wcsnrtombs(3),
wcstombs(3)