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Subject: Re: [boost] [multi_index] scalar insert interface
From: Maxim Yegorushkin (maxim.yegorushkin_at_[hidden])
Date: 2010-11-08 07:29:49

On 05/11/10 18:15, JOAQUIN M. LOPEZ MUÑOZ wrote:
> ________________________________________
> De: boost-bounces_at_[hidden] [boost-bounces_at_[hidden]] En nombre de Stewart, Robert [Robert.Stewart_at_[hidden]]
> Enviado el: viernes, 05 de noviembre de 2010 18:54
> Para: boost_at_[hidden]
> Asunto: Re: [boost] [multi_index] scalar insert interface
>> Maxim Yegorushkin wrote:
>>> In ordered_index there are two scalar insert overloads:
>>> std::pair<iterator,bool> insert(const value_type& x);
>>> iterator insert(iterator position,const value_type& x);
>>> The second version is lacking the bool result, which is sometimes
>>> required.
>> As is, it mirrors std::map's interface.
> Correct, this is exactly the rationale behind the difference in the
> result types of both overloads. Clever as Maxim's suggestion is,
> I'm reluctant to diverge from the standard without a compelling
> reason --here the benefit does not seem impressive, since there
> are efficient ways to determine whether the insertion took place,
> for instance checking size() before and after trying the insertion.

Performance-wise, it probably requires extra CPU cycles and storage
(cache) to check size before and after insertion.

I would still vote for another insert overload, maybe insert2() or
something, which returns that bool. Since internally final_insert_
always returns it, there is no good reason to waste it.


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