1#include <unistd.h>
 2#include <errno.h>
 3#include <limits.h>
 4
 5char *ttyname(int fd)
 6{
 7	static char buf[TTY_NAME_MAX];
 8	int result;
 9	if ((result = ttyname_r(fd, buf, sizeof buf))) {
10		errno = result;
11		return NULL;
12	}
13	return buf;
14}