- static char *s2;
- int fd;
- if (!s) {
- if (!s2) s2 = malloc(L_ctermid);
- s = s2;
- }
- fd = open("/dev/tty", O_WRONLY | O_NOCTTY);
- if (fd < 0)
- return strcpy(s, "");
- if (ttyname_r(fd, s, L_ctermid))
- strcpy(s, "");
- close(fd);
- return s;