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Subject: Re: [boost] Review request for variant2, review manager wanted
From: Niall Douglas (s_sourceforge_at_[hidden])
Date: 2019-02-25 21:13:19

>> These are very interesting and useful, thank you. I now have hard
>> evidence with which to persuade people at work that Boost.Variant needs
>> to be purged from our latency critical paths.
> Niall if you don't mind, we'd like to know what the largest number of
> types you have in a variant in that code base is.

Somewhere between five and twenty I think, depending on use case.
They're scattered all over.

For me the main problem is the hidden dynamic memory allocation which is
happening every state change inside a critical path. But we don't have
C++ 17 available, hence my great interest in variant2.

(We actually use a completely renamed fork of Boost, so all macros,
headers and namespaces are renamed with a custom prefix to prevent
collision with customer Boosts. This takes many hours to regenerate, so
we lag latest Boost considerably. Still, if there's a suitably pressing
need, it'll get regenerated in order to get Mp11 in order to get variant2)


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