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From: Natasha Kerensikova <lithiumcat@instinctive.eu>
Newsgroups: comp.lang.ada
Subject: Re: Safety of unprotected concurrent operations on constant objects
Date: Sun, 4 May 2014 15:57:02 +0000 (UTC)
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Date: 2014-05-04T15:57:02+00:00
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On 2014-05-04, sbelmont700@gmail.com <sbelmont700@gmail.com> wrote:
> On Sunday, May 4, 2014 3:46:00 AM UTC-4, Natasha Kerensikova wrote:
>> 
>> So I guess to correctly frame it as a question, that would be: how can I
>> 
>> have a map capable of concurrent reads with minimal wheel reinvention?
>> 
>
> You really can't.  You can either reinvent the wheel in your own
> task-safe manner,

I find it extremely hard to believe that there is no such wheel existing
out there. Standard containers and Booch components might not fit the
particular requirements, but I would bet there are some existing container
implementations that fit.

> or assume-the-worst about the standard map and surround it with a
> mutex.  Though, as was said, the split-seconds you would burn on the
> mutex would be negligible when compared to the network delay of
> supplying the results.

How would you "surround it with a mutex"? Do you mean a procedure in a
procted object, or some other scheme I'm not familiar with?

However, if I start assuming the worst about standard containers, I
might soon slip down the slope towards assuming the worst about all
others standard features. There is nothing in the ARM that prevents tag
checks or dispatching from being implemented through a splay tree or
some other concurrent-read-unsafe mechanism, is there? Should I mutex
those too then?