47 static int s_fd = -1;    /* fd of the AT channel */  variable
376             count = read(s_fd, p_read,  in readline()
484     if (s_fd < 0 || s_readerClosed > 0) {  in writeline()
495             written = write (s_fd, s + cur, len - cur);  in writeline()
508         written = write (s_fd, "\r" , 1);  in writeline()
523     if (s_fd < 0 || s_readerClosed > 0) {  in writeCtrlZ()
534             written = write (s_fd, s + cur, len - cur);  in writeCtrlZ()
547         written = write (s_fd, "\032" , 1);  in writeCtrlZ()
579     s_fd = fd;  in at_open()
604     if (s_fd >= 0) {  in at_close()
605         close(s_fd);  in at_close()
607     s_fd = -1;  in at_close()