Re: [boost] [variant2] documentation request

Subject: Re: [boost] [variant2] documentation request
From: Peter Dimov (lists_at_[hidden])
Date: 2019-03-03 21:43:39

Niall Douglas wrote:

> This is why I would suggest variant2 provide elemental 
> single_buffer_variant and double_buffer_variant, and let the end user 
> choose which they want.

variant2 presently is single_buffer_variant except that instead of giving 
you an error when that's not possible, it silently switches to 
double_buffer_variant and soldiers on. (Which happens rarely.)

I agree that one can make a good argument for (a variation of) 
double_buffer_variant, which prioritizes strong guarantee over sizeof. But 
that's only needed when your contained types don't have noexcept move. In 
this case, a not unreasonable course of action is to hold them by unique_ptr 
in the variant instead.