mbsnrtowcs — convert a multibyte string to a wide-character string
#define _GNU_SOURCE #include <wchar.h>
size_t mbsnrtowcs( |
wchar_t * | dest, |
| const char ** | src, | |
| size_t | nms, | |
| size_t | len, | |
| mbstate_t * | ps); |
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:
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.
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.
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.
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.
The behavior of mbsnrtowcs()
depends on the LC_CTYPE
category of the current locale.
Passing NULL as ps
is not multi-thread safe.
This page is part of release 2.79 of the Linux man-pages project. A
description of the project, and information about reporting
bugs, can be found at
http://www.kernel.org/doc/man-pages/.
|
Copyright (c) Bruno Haible <haibleclisp.cons.org> This is free documentation; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. References consulted: GNU glibc-2 source code and manual Dinkumware C library reference http://www.dinkumware.com/ OpenGroup's Single Unix specification http://www.UNIX-systems.org/online.html |