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Date: Tue, 02 Apr 2002 11:14:20 -0500
To: Randall R Schulz <rrschulz AT cris DOT com>, Stuart Brady <sbrady AT ntlworld DOT com>,
   Cygwin <cygwin AT cygwin DOT com>
From: "Larry Hall (RFK Partners, Inc)" <lhall AT rfk DOT com>
Subject: Re: Bash bug? - piped loops using builtin echo and stdout
In-Reply-To: <5.1.0.14.2.20020402074837.02a020e8@pop3.cris.com>
References: <Pine DOT LNX DOT 4 DOT 44 DOT 0204021320320 DOT 1603-100000 AT calypso DOT arrow>
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I can reproduce Stuart's problem on W2K.  I'm on a uni-processor machine.
I've only tried it interactively.  Removing the pipe from the process 
makes "foo" and "bar" alternate as expected.  With the pipe the result is:

 >while( true ); do echo foo; /bin/echo bar; done | cat
foo
bar
foo
bar
foo
bar
foo
bar
foo
foo
bar
bar
foo
bar
foo
foo
foo
bar
bar
bar
foo
foo
bar
bar
foo
foo
foo
bar
bar
bar
.
.
.

This is with Cygwin 1.3.10.  Just as an alternate data point to avoid too 
much emphasis on Stuart's configuration.

Larry Hall                              lhall AT rfk DOT com
RFK Partners, Inc.                      http://www.rfk.com
838 Washington Street                   (508) 893-9779 - RFK Office
Holliston, MA 01746                     (508) 893-9889 - FAX



At 10:56 AM 4/2/2002, Randall R Schulz wrote:
>Stuart,
>
>I have the same installation you report (Win2K) and cannot reproduce your problem. Hundreds of iterations work just fine.
>
>I do notice that on my two-CPU system this loop will consume almost 90% of the available CPU cycles and about 3/4 of that is kernel mode (as displayed by the "Performance" tab of the "Windows Task Manager").
>
>You don't say much about what is "going wrong," though, so it's hard to hypothesize a problem.
>
>Someone (but not me) might get something from the cygcheck output you mention. Personally, I prefer it in an attachment since it makes searching my local mail archive less likely to pick up a posting with in-line cygcheck output. Cygcheck output is not spam.
>
>Randall Schulz
>Mountain View, CA USA
>
>
>At 06:54 2002-04-02, Stuart Brady wrote:
>>With bash, is the behaviour of "while( true ); do echo foo; /bin/echo bar; done | cat" defined? Is it reasonable for me to expect to see "foo", "bar", "foo", "bar", and so on? With an interactive bash, this isn't what happens when I actually type the command in (i.e. sourcing or executing a script works fine). It only starts going wrong at around the 12th iteration. I can't see anything in the archives, and STFW didn't help either. Can anyone else reproduce this?
>>
>>I'm using Win2k with Cygwin 1.3.10-1 and bash 2.05a-3. This also occurs on Win98 with the same versions of Cygwin and bash, but does not occur on Red Hat 7.2 with bash 2.05-8, nor does it occur on Red Hat 7.0 with bash 2.04-11. Should I post the output of cygcheck -s -r -v here, since I'm not sure that this is even a bug, and am reluctant to spam people?
>>--
>>Stuart Brady
>
>
>--
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