WCSTOMBS(3) Library Functions Manual WCSTOMBS(3)
wcstombs -- converts a wide-character string to a multibyte character
Standard C Library (libc, -lc)
wcstombs(char * restrict s, const wchar_t * restrict pwcs, size_t n);
wcstombs() converts the nul-terminated wide-character string pointed to
by pwcs to the corresponding multibyte character string, and stores it in
the array pointed to by s. This function may modify the first at most n
bytes of 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 wcstombs() implies the result multibyte
character string pointed to by s always to begin with an initial state.
The behaviour of wcstombs() is affected by the LC_CTYPE category of the
These are the 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 to by pwcs. In this case, n is
pwcs == NULL Undefined (may cause 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 nul-
(size_t)-1 pwcs points to a string containing an invalid wide
character. wcstombs() also sets errno to indicate the
wcstombs() may cause an error in the following case:
[EILSEQ] pwcs points to a string containing an invalid wide
mbstowcs(3), setlocale(3), wctomb(3)
The wcstombs() function conforms to ANSI X3.159-1989 (``ANSI C89''). The
restrict qualifier is added at ISO/IEC 9899:1999 (``ISO C99'').
NetBSD 6.1.5 March 16, 2011 NetBSD 6.1.5