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From: "G.B." <bauhaus@notmyhomepage.invalid>
Newsgroups: comp.lang.ada
Subject: Re: Getting the index for an element in mutually referencing
 containers
Date: Sun, 12 Mar 2017 10:38:28 +0100
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Date: 2017-03-12T10:38:28+01:00
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On 12.03.17 09:22, Simon Wright wrote:
> Niklas Holsti <niklas.holsti@tidorum.invalid> writes:
>
>> On 17-03-11 23:46 , Simon Wright wrote:
>>
>>> Basically, I (Simon, now) am having trouble thinking of an
>>> application where reference counting would be an appropriate
>>> solution.
>>
>> How about this one: the SW generates messages (telemetry packets)
>> reporting various sorts of data and events.
>>
> [...]
>>
>> Each destination has a queue of incoming messages, and the queueing
>> and processing time for a given message varies accordingly. Rather
>> than copy the (possibly long) message into each destination's queue,
>> the queues hold references to a single, shared instance of the
>> message, dynamically allocated in a memory pool. These references are
>> counted. When, finally, all destinations have processed the message,
>> the message's reference count reaches zero, and the message can be
>> deallocated.
>>
>> This use of reference counting is a typical design in satellite
>> on-board SW.
>
> Thanks for the example!

A good one that should have a place in Ada Docs on Stackoverflow,
I think.

> I still have a feeling that this is an in-computer software technique
> which resolves a software problem, rather than a necessary response to
> an application-domain problem.

The radio operators, log inspectors, or message-monitoring staff
might feel overlooked after being changed into a software problem! ;-)