converts a wide-character string to a
multibyte character string
* restrict s, const
wchar_t * restrict pwcs,
converts the null-terminated wide-character string pointed to by
pwcs to the corresponding multibyte character string,
and stores up to n bytes in the array pointed to by
s. Each character 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
implies the result multibyte character string pointed to by
s always to begin with an initial state.
The behaviour of the
is affected by the
LC_CTYPE category of the current
There are special cases:
- s == NULL
wcstombs() returns the number of bytes to store the whole multibyte character string corresponding to the wide-character string pointed to by pwcs. In this case, n is ignored.
- pwcs == NULL
- Undefined (may causes the program to crash).
- 0 or positive
- Number of bytes stored in the array pointed to by s. 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 null-terminated.
- pwcs points the string containing invalid wide
wcstombs() also sets errno to indicate the error.
wcstombs() may cause an error in the
- pwcs Points to the string containing invalid wide character.
wcstombs() function conforms to
ANSI X3.159-1989 (“ANSI C89”).
The restrict qualifier is added at ISO/IEC 9899/1999 (“ISO