wcstombs - converts a wide character string to a multibyte character
Standard C Library (libc, -lc)
wcstombs(const char * restrict s, wchar_t * restrict pwcs, size_t n);
The wcstombs() converts the null-terminated wide character string pointed
by pwcs to the corresponding multibyte character string, and store it to
the array pointed by s. This function may modify the first at most n
bytes of the array pointed by s. Each characters will be converted as if
wctomb(3) is continuously called, except the internal state of wctomb(3)
will not be affected.
For state-dependent encoding, the wcstombs() implies the result multibyte
character string pointed by s always to begin with an initial state.
The behaviour of the wcstombs() is affected by LC_CTYPE category of the
There are special cases:
s == NULL The wcstombs() returns the number of bytes to store the
whole multibyte character string corresponding to the wide
character string pointed by pwcs. In this case, n is
pwcs == NULL undefined (may causes the program to crash).
The wcstombs() returns:
0 or positive
number of bytes stored to the array pointed by s. There is
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 by s will not be null-terminated.
(size_t)-1 pwcs points the string containing invalid wide character.
The wcstombs() also sets errno to indicate the error.
The wcstombs() may causes an error in the following case:
[EILSEQ] pwcs points the string containing invalid wide character.
The wcstombs() function conforms to ANSI X3.159-1989 (``ANSI C''). The
restrict qualifier is added at .
BSD February 4, 2002 BSD
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