NAME
wcsrtombs —
converts a wide-character
string to a multibyte character string (restartable)
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <wchar.h>
size_t
wcsrtombs(
char *
restrict s,
const wchar_t
** restrict pwcs,
size_t
n,
mbstate_t * restrict
ps);
DESCRIPTION
The
wcsrtombs() converts the nul-terminated wide-character
string indirectly pointed to by
pwcs to the
corresponding multibyte character string, and stores it in the array pointed
to by
s. The conversion stops due to the following
reasons:
- The conversion reaches a nul wide character. In this
case, the nul wide character is also converted.
- The wcsrtombs() has already stored
n bytes in the array pointed to by
s.
- The conversion encounters an invalid character.
Each character will be converted as if
wcrtomb(3) is continuously
called, except the internal state of
wcrtomb(3) will not be
affected.
After conversion, if
s is not a null pointer, the pointer
object pointed to by
pwcs is a null pointer (if the
conversion is stopped due to reaching a nul wide character) or the first byte
of the character just after the last character converted.
If
s is not a null pointer and the conversion is stopped
due to reaching a nul wide character,
wcsrtombs() places the
state object pointed to by
ps to an initial state after
the conversion is taken place.
The behaviour of
wcsrtombs() is affected by the
LC_CTYPE
category of the current locale.
These are the special cases:
-
-
- s == NULL
- wcsrtombs() returns the number of bytes
to store the whole multibyte character string corresponding to the
wide-character string pointed to by pwcs, not
including the terminating nul byte. In this case, n
is ignored.
-
-
- pwcs == NULL || *pwcs ==
NULL
- Undefined (may cause the program to crash).
-
-
- ps == NULL
- wcsrtombs() 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
wcsrtombs(), which is initialized at startup time of the
program.
RETURN VALUES
wcsrtombs() returns:
-
-
- 0 or positive
- Number of bytes stored in the array pointed to by
s, except for a nul byte. There are no cases that
the value returned is greater than n (unless
s is a null pointer). If the return value is equal
to n, the string pointed to by
s will not be nul-terminated.
-
-
- (size_t)-1
- pwcs points to a string containing an
invalid wide character. The wcsrtombs() also sets
errno to indicate the error.
ERRORS
wcsrtombs() may cause an error in the following case:
-
-
- [
EILSEQ
]
- pwcs points to a string containing an
invalid wide character.
SEE ALSO
setlocale(3),
wcrtomb(3),
wcstombs(3)
STANDARDS
The
wcsrtombs() function conforms to
ANSI
X3.159-1989 (“ANSI C89”). The restrict qualifier is
added at
ISO/IEC 9899:1999
(“ISO C99”).