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Date: Thu, 3 Feb 2005 10:19:55 +0100
From: Corinna Vinschen <corinna-cygwin AT cygwin DOT com>
To: cygwin AT cygwin DOT com
Subject: Re: Help about serial programming: manipulating DTR
Message-ID: <20050203091955.GD14580@cygbert.vinschen.de>
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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 AT cygwin DOT com
Red Hat, Inc.

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