1#include <uchar.h>
 2#include <wchar.h>
 3
 4size_t mbrtoc32(char32_t *restrict pc32, const char *restrict s, size_t n, mbstate_t *restrict ps)
 5{
 6	static unsigned internal_state;
 7	if (!ps) ps = (void *)&internal_state;
 8	if (!s) return mbrtoc32(0, "", 1, ps);
 9	wchar_t wc;
10	size_t ret = mbrtowc(&wc, s, n, ps);
11	if (ret <= 4 && pc32) *pc32 = wc;
12	return ret;
13}