MBSRTOWCS(3) Linux Programmer's Manual MBSRTOWCS(3)
NAME
mbsrtowcs - convert a multibyte string to a wide-character string
SYNOPSIS
#include <wchar.h>
size_t mbsrtowcs(wchar_t *dest, const char **src,
size_t len, mbstate_t *ps);
DESCRIPTION
If dest is not NULL, the mbsrtowcs() function converts 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 mbr-
towc(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. 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 re-
turned.
3. The multibyte string has been completely converted, including the
terminating null wide character ('\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, exclud-
ing the terminating null wide 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 mem-
ory, and that no length limit exists.
In both of the above cases, if ps is NULL, a static anonymous state
known only to the mbsrtowcs() function is used instead.
The programmer must ensure that there is room for at least len wide
characters at dest.
RETURN VALUE
The mbsrtowcs() 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.
ATTRIBUTES
For an explanation of the terms used in this section, see at-
tributes(7).
+------------+---------------+------------------------------+
|Interface | Attribute | Value |
+------------+---------------+------------------------------+
|mbsrtowcs() | Thread safety | MT-Unsafe race:mbsrtowcs/!ps |
+------------+---------------+------------------------------+
CONFORMING TO
POSIX.1-2001, POSIX.1-2008, C99.
NOTES
The behavior of mbsrtowcs() depends on the LC_CTYPE category of the
current locale.
Passing NULL as ps is not multithread safe.
SEE ALSO
iconv(3), mbrtowc(3), mbsinit(3), mbsnrtowcs(3), mbstowcs(3)
COLOPHON
This page is part of release 5.07 of the Linux man-pages project. A
description of the project, information about reporting bugs, and the
latest version of this page, can be found at
https://www.kernel.org/doc/man-pages/.
GNU 2019-03-06 MBSRTOWCS(3)