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Date: Wed, 6 Dec 2000 14:37:06 -0500
From: Christopher Faylor <cgf AT redhat DOT com>
To: cygwin support <cygwin AT cygwin DOT com>
Subject: Re: O_NONBLOCK serial I/O blocks on 95, OK on NT
Message-ID: <20001206143706.A9630@redhat.com>
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In-Reply-To: <4.3.1.2.20001206142217.02101860@pop.ma.ultranet.com>; from lhall@rfk.com on Wed, Dec 06, 2000 at 02:23:29PM -0500

On Wed, Dec 06, 2000 at 02:23:29PM -0500, Larry Hall (RFK Partners, Inc) wrote:
>At 02:08 PM 12/6/2000, Bruce Edge wrote:
>>I'm opening /dev/com1 as follows:
>>  fd  = open( "/dev/com1", O_RDWR | O_NOCTTY | O_NONBLOCK | O_BINARY ); 
>>
>>on NT the O_NONBLOCK works fine.
>>on win 95, read( fd, buf, max_len ) blocks.
>>
>>I don't think the termios stuff should affect this, at least if it did, I
>>should be having the same problem under NT.
>>Is there a fix for this?
>>Or, is there any way to check for chars pending before reading?
>>I'm already using select(), which shouldn't even drop out of the wait until
>>there's data.
>
>
>Perhaps this is related to this?
>
>http://sources.redhat.com/ml/cygwin/2000-11/msg01544.html
>
>If so, you may find some insight by reading this thread...

It's unlikely that this has any bearing.  This is a thread on pipes.  They
use different mechanisms from serial I/O.

Serial I/O in cygwin uses MS overlapped I/O.  Maybe this isn't completely
implemented on w9x.

cgf

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