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Date:	Mon, 16 Jul 2001 17:30:30 +0200
From:	Kurt Roeckx <Q AT ping DOT be>
To:	cygwin AT cygwin DOT com
Subject:	Re: select on the parallel port, and non-blocking io
Message-ID:	<20010716173030.A6890@ping.be>
References:	<20010716172736 DOT A6856 AT ping DOT be>
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In-Reply-To:	<20010716172736.A6856@ping.be>

On Mon, Jul 16, 2001 at 05:27:36PM +0200, Kurt Roeckx wrote:
> I use select on 2 fds, one of which is the parallel port.
> 
> The parallel port was opened like this: 
> 
> 	port = open("lpt1", O_RDWR, O_NONBLOCK);
> 
> There shouldn't be any data on the port, since there is no device
> attached, or it's powered down (I tried both).  Yes select() says
> I can read from it, and blocks on it.

Oh, I forgot to mention something.  If I change lpt1 into com1,
things work perfect.  Select() doesn't say there is data to read,
and if I try to read from it, it returns -1, with errno set to
EAGAIN, as expected.


Kurt


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