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Date: Thu, 28 Sep 2006 00:10:18 +0100
From: ahnkle <cygwin AT ekers DOT idps DOT co DOT uk>
To: cygwin AT cygwin DOT com
Subject: Re: tcgetattr problem
Message-ID: <20060927231017.GC29552@flixx.linux.bogus>
References: <20060927193049 DOT GA29552 AT flixx DOT linux DOT bogus> <Pine DOT GSO DOT 4 DOT 63 DOT 0609271833460 DOT 15013 AT access1 DOT cims DOT nyu DOT edu>
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On 18:36 Wed 27 Sep     , Igor Peshansky wrote:
> 
> #define PORT "com1"
> ...
>   fd = open(PORT, O_RDWR | O_NOCTTY );
> 
> There's your problem.  When you open a port as "com1", it looks like a
> file to Cygwin, since it doesn't recognize it as a valid device name.
> Thus any attempt to manipulate that fd as a device will fail.
> 
> Use the Cygwin device (e.g., "/dev/ttyS0").

Strangely, com1 *does* work in the call to open. Having tried "/dev/ttyS0",
tcgetattr() works ok.

I also note that read() and write() work ok too using "com1", but
tcsetattr() also fails.

BTW, I obtained the CVS source, but couldn't find the _ioctl() call 
anywhere in my (brief) grepping. Is there any documentation about internal
structure, and whats going on under the hood?

regards,
ahnkle


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