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Date: Sun, 31 May 2020 03:48:14 -0700 (PDT)
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Subject: Re: Contracts for protected objects: internal call cannot appear in
 precondition of protected operation
From: reinert <reinkor@gmail.com>
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Xref: reader01.eternal-september.org comp.lang.ada:58898
Date: 2020-05-31T03:48:14-07:00
List-Id: <comp.lang.ada>

Thanks, Got it :-)

reinert

fredag 29. mai 2020 04.11.49 UTC+2 skrev Randy Brukardt f=C3=B8lgende:
> That's not allowed, as it would require extra mutual exclusion. Since tha=
t=20
> exclusion would have to be separate from the protected action (necessary=
=20
> since the entry may not be open when the call is made), you'd also have a=
=20
> race condition (the precondition could be evaluated with one value, the=
=20
> value then changed, and then later the entry accepted). Best practices is=
=20
> always that preconditions should only depend on the parameters to a call=
=20
> (regardless of the kind of call involved).
>=20
>                         Randy.
>=20
> ....