Mailing-List: contact cygwin-help@cygwin.com; run by ezmlm List-Subscribe: List-Archive: List-Post: List-Help: , Sender: cygwin-owner@cygwin.com Mail-Followup-To: cygwin@cygwin.com Delivered-To: mailing list cygwin@cygwin.com Date: Thu, 3 Feb 2005 10:19:55 +0100 From: Corinna Vinschen To: cygwin@cygwin.com Subject: Re: Help about serial programming: manipulating DTR Message-ID: <20050203091955.GD14580@cygbert.vinschen.de> Reply-To: cygwin@cygwin.com Mail-Followup-To: cygwin@cygwin.com References: <6.0.1.1.0.20050202171834.01fcf4f8@192.168.2.1> <20050202180929.GQ31117@cygbert.vinschen.de> <6.0.1.1.0.20050203091915.02128f78@192.168.2.1> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <6.0.1.1.0.20050203091915.02128f78@192.168.2.1> User-Agent: Mutt/1.4.2i On Feb 3 09:52, llandre wrote: > > >> I'm trying to manipulate the DTR signal of the serial port. > >> As an example I used this code snippet: > >> http://lists.exploits.org/upsdev/Feb2004/00013.html. > >> I can open the com1, I can send and receive data but the ioctl I use > >> to read the status of the signals returns -1: > >> > >> int status; > >> ioctl(upsfd, TIOCMGET, &status); > >> > >> Anybody can help me? I have no idea about what's wrong with this code. > > > >strace would give a hint. TIOCMGET should only fail because a call to > >GetCommModemStatus fails. If so, the strace would contain a line which > >talks about setting errno in fhandler_serial::ioctl. > > Corinna, > > thanks a lot for your advice. > I tried to use strace. Here is what I see: That's not enough information, so I try an educated guess. It looks like the file you opened is not recognized as serial interface. What did you use as device name? FYI, it should be either "/dev/com1" or /dev/ttyS0" for the first serial. Corinna -- Corinna Vinschen Please, send mails regarding Cygwin to Cygwin Project Co-Leader mailto:cygwin@cygwin.com Red Hat, Inc. -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/