NAME
mbsnrtowcs - convert a multibyte string to a wide-character string
SYNOPSIS
#define _GNU_SOURCE
#include <wchar.h>
size_t mbsnrtowcs(wchar_t *dest, const char **src,
size_t nms, size_t len, mbstate_t *ps);
DESCRIPTION
The mbsnrtowcs() function is like the mbsrtowcs(3) function, except
that the number of bytes to be converted, starting at *src, is limited
to nms.
If dest is not a NULL pointer, the mbsnrtowcs() function converts at
most nms bytes from the multibyte string *src to a wide-character
string starting at dest. At most len wide characters are written to
dest. The shift state *ps is updated. The conversion is effectively
performed by repeatedly calling mbrtowc(dest, *src, n, ps) where n is
some positive number, as long as this call succeeds, and then
incrementing dest by one and *src by the number of bytes consumed. The
conversion can stop for three reasons:
1. An invalid multibyte sequence has been encountered. In this case
*src is left pointing to the invalid multibyte sequence, (size_t) -1
is returned, and errno is set to EILSEQ.
2. The nms limit forces a stop, or len non-L'\0' wide characters have
been stored at dest. In this case *src is left pointing to the next
multibyte sequence to be converted, and the number of wide
characters written to dest is returned.
3. The multibyte string has been completely converted, including the
terminating '\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 wide characters written to dest, excluding the terminating
L'\0' character, is returned.
If dest is NULL, len is ignored, and the conversion proceeds as above,
except that the converted wide characters are not written out to
memory, and that no destination length limit exists.
In both of the above cases, if ps is a NULL pointer, a static anonymous
state only known to the mbsnrtowcs function is used instead.
The programmer must ensure that there is room for at least len wide
characters at dest.
RETURN VALUE
The mbsnrtowcs() function returns the number of wide characters that
make up the converted part of the wide-character string, not including
the terminating null wide character. If an invalid multibyte sequence
was encountered, (size_t) -1 is returned, and errno set to EILSEQ.
CONFORMING TO
This function is a GNU extension.
NOTES
The behavior of mbsnrtowcs() depends on the LC_CTYPE category of the
current locale.
Passing NULL as ps is not multithread safe.
SEE ALSO
iconv(3), mbsrtowcs(3)
COLOPHON
This page is part of release 3.24 of the Linux man-pages project. A
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be found at http://www.kernel.org/doc/man-pages/.