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Date: Fri, 7 Jul 2006 12:17:13 +0200
From: Corinna Vinschen <corinna-cygwin AT cygwin DOT com>
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Subject: Re: rsync over ssh hang issue understood
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On Jul  7 09:58, Darryl Miles wrote:
> Corinna Vinschen wrote:
> >On Jul  7 08:43, Darryl Miles wrote:
> >>What was the reason the existing code in CVS for select.cc was disabled?
> >>
> >>Maybe it would help to better understand the reasons/cases where the 
> >>disabled code failed.
> >
> >Hangs with native Windows applications, AFAIR.
> 
> I take this to mean a CYGWIN app is on one end and a native app on the 
> other.
> 
> Remember the test case ?

I think native versions of unison uncovered the problem when
connecting with Cygwin versions of unison.  Search the archives,
there must be some discussions about this.

> When it hangs can you remember who was reading and who was writing.

Sorry, no.  Should be in the archives, though.

> In MSDN there is:
> 
> "The pipe server should not perform a blocking read operation until the 
> pipe client has started.  Otherwise, a race condition can occur.  This 
> typically occurs when initialization code, such as the C run-time, needs 
> to lock and examine inherited handles."
> 
> Could this be related ?  Does anyone on the list know the background of 
> the statement, it sounds like a Windows documented bug/feature.

Check out pipe.cc.  The CreateNamedPipe call creating the server side is
the reader, the client is the writer.  Since the CreateNamedPipe/
CreateFile is done in one go, I don't see how that could be the problem.


Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Project Co-Leader          cygwin AT cygwin DOT com
Red Hat

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