[Newbies] Read a filestream (named pipe) with a timeout

Ron Teitelbaum ron at usmedrec.com
Thu Jan 9 21:16:25 UTC 2014

Hi Dave,

See #dataAvailable  and #recieveAvailableData.

It's never good to call for data if you don't know you have any.  Better to
setup a wait for data until call instead.  

All the best,

Ron Teitelbaum
Head Of Engineering
3d Immersive Collaboration Consulting
ron at 3dicc.com
Follow Me On Twitter: @RonTeitelbaum

> -----Original Message-----
> From: beginners-bounces at lists.squeakfoundation.org [mailto:beginners-
> bounces at lists.squeakfoundation.org] On Behalf Of dsl101
> Sent: Thursday, January 09, 2014 10:16 AM
> To: beginners at lists.squeakfoundation.org
> Subject: [Newbies] Read a filestream (named pipe) with a timeout
> I'm using Squeak 4.2 and working on the smalltalk end of a named pipe
> connection, which sends a message to the named pipe server with:
> 	msg := 'Here''s Johnny!!!!'.
> 	pipe nextPutAll: msg; flush.
> It should then receive an acknowledgement, which will be a 32-byte md5
hash of
> the received message (which the smalltalk app can then verify). It's
possible the
> named pipe server may have gone away or otherwise been unable to deal with
> the request, and so I'd like to set a timeout on reading the
> I've tried using this:
> 	ack := [ pipe next: 32 ] valueWithin: (Duration seconds: 3)
onTimeout: [
> 'timeout'. ].
> and then made the pipe server pause artificially to test the code. But the
> smalltalk thread blocks on the read and doesn't carry on (even after the
> timeout), although if I then get the pipe server to send the correct
> (after a 5 second delay, for example), the value of 'ack' is 'timeout'.
> the timeout did what it's supposed to do, but couldn't 'unblock' the
> read on the pipe.
> Is there a way to accomplish this even with a blocking FileStream read?
I'd rather
> avoid a busy wait on there being 32 characters available if at all
> Thanks,
> Dave
> --
> View this message in context:
> pipe-with-a-timeout-tp4735456.html
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