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Command: mbsrtowcs | Section: 3 | Source: NetBSD | File: mbsrtowcs.3
MBSRTOWCS(3) FreeBSD Library Functions Manual MBSRTOWCS(3)
NAME
mbsrtowcs, mbsrntowcs - converts a multibyte character string to a wide-
character string (restartable)
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <wchar.h>
size_t
mbsrtowcs(wchar_t * restrict pwcs, const char ** restrict s, size_t n,
mbstate_t * restrict ps);
size_t
mbsnrtowcs(wchar_t * restrict pwcs, const char ** restrict s, size_t nmc,
size_t n, mbstate_t * restrict ps);
DESCRIPTION
The mbsrtowcs() function converts the multibyte character string
indirectly pointed to by s to the corresponding wide-character string,
and stores it in the array pointed to by pwcs. The conversion stops due
to the following reasons:
o The conversion reaches a NUL byte. In this case, the NUL byte is
also converted.
o The mbsrtowcs() has already stored n wide characters.
o The conversion encounters an invalid character.
Each character will be converted as if mbrtowc(3) is continuously called.
After conversion, if pwcs is not a NULL pointer, the pointer object
pointed to by s is a NULL pointer (if the conversion is stopped due to
reaching a NUL byte) or the first byte of the character just after the
last character converted.
If pwcs is not a NULL pointer and the conversion is stopped due to
reaching a NUL byte, the mbsrtowcs() places the state object pointed to
by ps to an initial state after the conversion has taken place.
The behaviour of mbsrtowcs() is affected by the LC_CTYPE category of the
current locale.
These are the special cases:
s == NULL || *s == NULL
Undefined (may cause the program to crash).
pwcs == NULL The conversion has taken place, but the resulting wide-
character string was discarded. In this case, the
pointer object pointed to by s is not modified and n is
ignored.
ps == NULL The mbsrtowcs() uses its own internal state object to
keep the conversion state, instead of ps mentioned in
this manual page.
Calling any other functions in Standard C Library
(libc, -lc) never changes the internal state of
mbsrtowcs(), which is initialized at startup time of
the program.
The mbsnrtowcs() function behaves identically to mbsrtowcs(), except that
the conversion stops after reading at most nmc characters from the buffer
pointed to by s.
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 pwcs, except for a terminating
NUL wide character (if any). If pwcs is not NULL and
the value returned is equal to n, the wide-character
string pointed to by pwcs is not NUL-terminated. If
pwcs is a NULL pointer, the value returned is the
number of elements to contain the whole string
converted, except for a terminating NUL wide character.
(size_t)-1 The array indirectly pointed to by s contains a byte
sequence forming invalid character. In this case,
mbsrtowcs() sets errno to indicate the error.
ERRORS
The mbsrtowcs() and mbsnrtowcs() functions may fail with the following
errors:
[EILSEQ] s points to a string containing 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 was added by ISO/IEC 9899:1999
("ISO C99").
The mbsnrtowcs() function conforms to IEEE Std 1003.1-2008 ("POSIX.1").
FreeBSD 14.1-RELEASE-p8 September 9, 2024 FreeBSD 14.1-RELEASE-p8