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