1#include <wchar.h>
2
3wchar_t* wcsncat(wchar_t* restrict d, const wchar_t* restrict s, size_t n) {
4    wchar_t* a = d;
5    d += wcslen(d);
6    while (n && *s)
7        n--, *d++ = *s++;
8    *d++ = 0;
9    return a;
10}
11