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Message-ID: <42743E33.1020700@1979.usna.com>
Date: Sat, 30 Apr 2005 22:25:55 -0400
From: "Jerry D. Hedden" <jdhedden AT 1979 DOT usna DOT com>
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To: cygwin AT cygwin DOT com
Subject: Re: cygwin-1.5.16-1: FIFOs broken
References: <427424F9 DOT 8060209 AT 1979 DOT usna DOT com> <20050501010945 DOT GB21071 AT trixie DOT casa DOT cgf DOT cx>
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Christopher Faylor wrote:
> On Sat, Apr 30, 2005 at 08:38:17PM -0400, Jerry D. Hedden wrote:
> 
>>I have a client-server application written in Perl that reads and writes 
>>using FIFOs.  It works fine under cygwin-1.5.15-1, but fails under 
>>cygwin-1.5.16-1 because it cannot read from the FIFO.
>>
>>To test this, open two shells.  In one shell, type:
>>cd /tmp
>>mkfifo FIFO
>>cat <FIFO
>>
>>In the other shell, you can send text to the first shell using:
>>cd /tmp
>>echo YOUR TEXT HERE >>FIFO
>>
>>After you're done, just ^C in the first window.
>>
>>Under 1.5.15, the above works fine.
>>
>>Under 1.5.16, no text goes through the FIFO.  Further, the echo command 
>>hangs, and will not terminate with ^C.  A 'ps' shows an 'O' for this 
>>stuck shell.  You have to do a kill -9 on the shell to terminate it.
> 
> As I mentioned in another enjoyable thread last week, fifos are only
> just barely working in cygwin.  They are still a work in progress.
> 
> However, that said, the above WJFFM.  In fact, it works more like linux
> in 1.5.16 than it does on 1.5.15, i.e., the cat command exits after
> printing "YOUR TEXT HERE" whereas it continues to block in 1.5.15.

I tried the 4/30 snapshot of cygwin1.dll.  It exhibited the behavior you 
mentioned with the 'cat' exiting after it reads text.  However, this is 
a bad thing.  It means that the FIFO is being set EOF after there is no 
more data.  I tried my client-server app with the snapshot cygwin1.dll, 
and it failed because of this.

It seems to me that the behavior of FIFOs under 1.5.15 was correct, and 
that under both 1.5.16 and the snapshot, FIFOs are now broken.

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