[boost] Re: Singleton: review

From: Andreas Huber (ahd6974-spamgroupstrap_at_[hidden])
Date: 2005-05-16 17:33:09

Andrei Alexandrescu (See Website For Email) wrote:
> Gennadiy Rozental wrote:
>>>> Author does admit that multithreading issues were not considered.
>>>> IMO any singleton design that doesn't cover MT couldn't be
>>>> accepted as generic.
>>>
>>> Not every library in Boost is MT safe even when it could be useful.
>>> MT was left into next stage.
>>
>> You could not leave MT for the next stage of singleton design.
>> Singletons have a long history dealing with MT issues topped with DL
>> idiom.
>
> I agree with Gennadiy (in case he's right; I haven't looked at the
> implementation). A Singleton without careful design for MT is IMHO
> unacceptable, no matter how carefully designed it is in any other
> dimension. Singleton is a shared object, and it must address MT issues
> first and foremost.

FWIW, that's also my opinion. More often than not singletons are 
accessed by multiple threads. A singleton lib that's not designed for MT 
is therefore of little help in many applications. I planned to do a 
(late) review but given that MT wasn't considered in the initial design 
I'm not too motivated anymore. Also, - as mentioned by other people - 
what I find a little bothersome is that the library apparently had very 
little real-world exposure (given the small timeframe from inception to 
review). Sure, such exposure isn't a requirement but it surely helps to 
make the library ready for review, i.e. reasonably mature.

-- 
Andreas Huber
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