wcsncat.c\string\src - musl - musl - an implementation of the standard library for Linux-based systems

#include <wchar.h>
wchar_t *wcsncat(wchar_t *d, const wchar_t *s, size_t n)
{
	wchar_t *a = d;
	d += wcslen(d);
	while (n && *s) n--, *d++ = *s++;
	*d++ = 0;
	return a;
}