[darcs-users] Unexpected wait return code

David Roundy droundy at abridgegame.org
Sat Nov 13 15:21:03 UTC 2004

On Wed, Nov 10, 2004 at 11:20:35PM +1100, Robert Leftwich wrote:
> I'm running Darcs 1.0.0 on W2000 and I occasionally get the following error 
> when issuing commands (whatsnew, pull, record, etc) :
>     awaitRequests: unexpected wait return code 4294967295
> Google-ing turns up one email on the Haskell list with a similar problem 
> back in March, but no-one answered it.
> It doesn't appear to stop anything from working, but should I be concerned?

Actually, I've seen this message myself, helping a friend set up darcs on
windows, and am curious as to what the deal is.

Do any of the windows developers have an idea what this is? I certainly
don't.  I *can* confirm that darcs never calls awaitRequests directly, so
probably this is something internal to the ghc RTS or to the standard

> PS I use a dual CPU machine and I'm curious if Darcs can take advantage of 
> this setup?

Alas, no.  Well, to a very slight extent.  Compressing and decompressing
files is done in a separate thread, so that could happen in parallel with
parsing, but this is so fast that it's not really worth it.  It's done in a
separate thread for other reasons than speed.

Automatic multithreading of haskell code for speed, as I understand it, is
still a research problem.  There is trickiness arising from the fact that
it is a lazy language, so you could (if not careful) end up spending a lot
of time computing results that are never used.  Also in this category is
the danger of introducing space leaks.
David Roundy

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