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From: "Le" <snelson1@llnl.gov>
Newsgroups: comp.lang.ada
Subject: Re: Palatable Windows IO using Ada
Date: 7 Apr 2006 09:30:23 -0700
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Date: 2006-04-07T09:30:23-07:00
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Your attempt at a tutorial is in error in a couple of places. Stating
that an application "should know" what will be returned is
presumptuous. Note this is a legacy application, so obviously there are
some devices out there which give varying responses. These are raw byte
sequences - no blocks or lines. Those esternal device ICDs are not
typically in the control of a system designer.

The ReadFile interface *is* blocking.  Overlap allows an app to come
back and see if it is done.  If not, assuming timeout wasn't used, one
must then cancel the IO or some other cleanup.

With respect to buffering, my point was that doing byte at a time IO to
get around the blocking nature of the API defeats the efficiencies
presumably provided by the driver's internal buffering.