fdevname_r
int fdevname_r(int, char *, size_t);
if (((error = fdevname_r(fd, buf, sizeof fdevname_buf))) != 0) {
if (((error = fdevname_r(fd, buf+used, sizeof(ptsname_buf)-used))) != 0) {
if (fdevname_r(STDIN_FILENO, dname +