wcsnrtombs - convert a wide-character string to a multibyte string
size_t wcsnrtombs(char *dest, const wchar_t **src, size_t nwc,
size_t len, mbstate_t *ps);
Feature Test Macro Requirements for glibc (see feature_test_macros
- Since glibc 2.10:
- _POSIX_C_SOURCE >= 200809L
- Before glibc 2.10:
() function is like the wcsrtombs
except that the number of wide characters to be converted, starting at
, is limited to nwc
is not NULL, the wcsnrtombs
() function converts at most
wide characters from the wide-character string *src
multibyte string starting at dest
. At most len
bytes are written
. The shift state *ps
is updated. The conversion is
effectively performed by repeatedly calling wcrtomb(dest, *src, ps)
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
- 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
- nwc wide characters have been converted without encountering a null
wide character (L'\0'), or 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 (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.
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 destination length limit exists.
In both of the above cases, if ps
is NULL, a static anonymous state known
only to the wcsnrtombs
() function is used instead.
The programmer must ensure that there is room for at least len
() 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,
is returned, and errno
set to EILSEQ
For an explanation of the terms used in this section, see attributes
The behavior of wcsnrtombs
() depends on the LC_CTYPE
the current locale.
Passing NULL as ps
is not multithread safe.