scc

 1#include <string.h>
 2#include <limits.h>
 3#include <wchar.h>
 4
 5#undef wcsrtombs
 6
 7size_t
 8wcsrtombs(char *restrict dest, const wchar_t **restrict src,
 9          size_t len, mbstate_t *restrict ps)
10{
11	size_t cnt, n;
12	wchar_t wc;
13	char buf[MB_LEN_MAX];
14
15	for (n = 0; ; n += cnt) {
16		wc = **src;
17		cnt = wcrtomb(buf, wc, ps);
18		if (cnt == (size_t) -1)
19			return -1;
20
21		if (dest) {
22			if (n+cnt > len)
23				return n;
24			memcpy(dest+n, buf, cnt);
25		}
26		*src += 1;
27
28		if (wc == L'\0')
29			break;
30	}
31	*src = NULL;
32
33	return n;
34}