wcsrtombs - convert a wide-character string to a multibyte string
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
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
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
The length limit forces a stop. In this case,
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
*src is set to NULL, and the number of bytes written to
dest, excluding the terminating null byte ('\0'), is
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
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.
This page is part of release 5.10 of the Linux
project. A description of the project, information about reporting bugs,
and the latest version of this page, can be found at