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From: "Pat Rogers" <progers@classwide.com>
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Subject: Re: newbie can't get exceptions to work!
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"Samuel T. Harris" <u61783@gsde.hou.us.ray.com> wrote in message
news:3AD46B6E.6A8592A@gsde.hou.us.ray.com...
<snip>
> Since a dynamic dispatching call involves a access to a class-wide
> type <snip>

Too strong.  Dynamic dispatching requires a class-wide *value*, which thus
includes class-wide parameters and class-wide view conversions, in addition
to dereferenced class-wide access values.  It is certainly the case that
class-wide access types are common due to their flexibility, but that isn't
the only way to get the class-wide value that then causes dispatching.

Lest there by any confusion (Sam already knows this, of course), there is
really only one rule here: dynamic dispatching only occurs when a class-wide
value is passed as the actual parameter to a primitive operation of a type
in the derivation class.


---
Patrick Rogers                       Consulting and Training in:
http://www.classwide.com        Real-Time/OO Languages
progers@classwide.com          Hard Deadline Schedulability Analysis
(281)648-3165                          Software Fault Tolerance