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Subject: Problem report: pipes and suspending do not work well together
Date: Thu, 10 Oct 2002 17:29:33 +0300
Message-ID: <26574F0076BFF449ADAE582D9E67780C0B7FF2@esebe006.ntc.nokia.com>
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From: <juhani DOT rantanen AT nokia DOT com>
To: <cygwin AT cygwin DOT com>
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Hello and thanks for your attention,

I am using the newest Cygwin net release (upgraded today by re-running Cygwin Setup to make sure this is not fixed yet). I noticed this problem while writing a long pipeline ending with "| less" and then trying to suspend the processes. When I do this the Cygwin window hangs until I kill the processes in the pipeline with "kill" or Windows Task Manager. The simplest testcase I've managed to find is:

cat README | less  # press ^Z immediately, hangs. Scroll to the bottom and works

This one always fails, naturally...

yes | less

I can reproduce the former case with any text file that is at least 16k long, probably the true value is the number of bytes "less" reads from a pipe when it starts, and this bug happens if you suspend a pipeline where a writer is currently writing to a pipe and blocked because reader hasn't read the data yet. Can't suggest any fixes though.

If you have any questions, please Cc: to me also because I'm not on the list.

BR,
-- 
Juhani Rantanen

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