Can anyone give me an code example of using the TIOCMIWIAT command. how do the different functions in serial.c i.e check_modem_status() and rs_interrupt_single() interact with rs_ioctl() while rs_ioctl is sleeping with in case TIOCMIWAIT to check for a status change e.g CTS change on the serial port lines. Naveed This email and any files attached are intended for the addressee and may contain information of a confidential nature. If you are not the intended recipient, be aware that this email was sent to you in error and you should not disclose, distribute, print, copy or make other use of this email or its attachments. Such actions, in fact, may be unlawful. In compliance with the various Regulations and Acts, General Dynamics UK Limited reserves the right to monitor (and examine for viruses) all emails and email attachments, both inbound and outbound. Email communications and their attachments may not be secure or error- or virus-free and the company does not accept liability or responsibility for such matters or the consequences thereof. Registered Office: 100 New Bridge Street, London EC4V 6JA. Registered in England and Wales No: 1911653. -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/