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Command: mbsrtowcs | Section: 3 | Source: OpenBSD | File: mbsrtowcs.3
MBSRTOWCS(3) FreeBSD Library Functions Manual MBSRTOWCS(3)
NAME
mbsrtowcs, mbsnrtowcs - converts a multibyte character string to a wide-
character string (restartable)
SYNOPSIS
#include <wchar.h>
size_t
mbsrtowcs(wchar_t * restrict dst, const char ** restrict src, size_t len,
mbstate_t * restrict ps);
size_t
mbsnrtowcs(wchar_t * restrict dst, const char ** restrict src,
size_t nmc, size_t len, mbstate_t * restrict ps);
DESCRIPTION
The mbsrtowcs() function converts the multibyte character string
indirectly pointed to by src to the corresponding wide-character string
and stores it in the array pointed to by dst. The conversion stops due
to the following reasons:
o The conversion reaches a null byte. In this case, the null byte is
also converted.
o The conversion has already stored len wide characters.
o The conversion encounters an invalid character.
The mbsnrtowcs() function is equivalent to mbsrtowcs() except that it
will additionally stop the conversion after processing nmc bytes.
Each character is converted as if mbrtowc(3) is continuously called.
After conversion, if dst is not a null pointer, the pointer object
pointed to by src is a null pointer (if the conversion is stopped due to
reaching a null byte) or the address just past the last byte processed.
If dst is not a null pointer and the conversion is stopped due to
reaching a null byte, the state object pointed to by ps is set to an
initial state after the conversion has taken place.
The behaviour of the mbsrtowcs() and mbsnrtowcs() functions is affected
by the LC_CTYPE category of the current locale.
There are two special cases:
dst == NULL The conversion takes place, but the resultant wide-
character string is discarded. In this case, the pointer
object pointed to by src is not modified and len is
ignored.
ps == NULL The mbsrtowcs() and mbsnrtowcs() functions use their own
internal state objects to keep the conversion state,
instead of ps as mentioned in this manual page.
Calling any other functions in libc never change these
internal states, which are initialized at startup time of
the program.
RETURN VALUES
The mbsrtowcs() and mbsnrtowcs() functions return:
0 or positive
The value returned is the number of elements stored in the
array pointed to by dst, except for a terminating null wide
character (if any). If dst is not null and the value
returned is equal to len, the wide-character string pointed
to by dst is not null terminated. If dst is a null
pointer, the value returned is the number of elements to
contain the whole string converted, except for a
terminating null wide character.
(size_t)-1 The array indirectly pointed to by src contains a byte
sequence forming invalid character. In this case, errno is
set to indicate the error.
ERRORS
The mbsrtowcs() and mbsnrtowcs() functions may return the following
errors:
[EILSEQ] The pointer pointed to by src points to an invalid or
incomplete multibyte character.
[EINVAL] ps points to an invalid or uninitialized mbstate_t
object.
SEE ALSO
mbrtowc(3), mbstowcs(3), setlocale(3)
STANDARDS
The mbsrtowcs() function conforms to ISO/IEC 9899/AMD1:1995 ("ISO C90,
Amendment 1"). The restrict qualifier is added at ISO/IEC 9899/1999
"(ISO C99)".
The mbsnrtowcs() function conforms to IEEE Std 1003.1-2008 ("POSIX.1").
FreeBSD 14.1-RELEASE-p8 June 5, 2013 FreeBSD 14.1-RELEASE-p8