Re: Problem with -gnatt

[Stephen Leake <stephen_leake@acm.org>]

"Matthew Heaney" <mheaney@on2.com> writes:

> "Alex R. Mosteo" <devnull@mailinator.com> wrote in message
> news:417377F7.7050506@mailinator.com...
> >
> > Sole instance of a Map:
> >
>
http://deepsix.homeip.net/svn/Adagio%20head/src/download/adagio-download-manager.adb
> 
> Note that protected operations should only execute "for a short time."  

I wish Robert Dewar were here. I suspect he would say something like
"Rubbish!".

"a short time" is not definable in any meaningful _standard_ way. It
is _totally_ up to the user to decide what that means.

If your application can afford to wait an hour for a protected object,
then an hour is "a short time". 

> Your Http_Report_Downloads protected operation could take longer
> than a "short time," if the map is large. Consider using a semaphore
> style lock, something like:
> 
> procedure Http_Report_Downloads (...) is
>    Control : Control_Type (Semaphore'Access);
> begin
>    ... -- safely manipulate map that you now have locked
> end;
> 

Since the user can forget to declare the Control object, this is _not_
as safe as wrapping the operations in a protected type.


-- Stephe
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