Re: [Boost-users] Usage of Boost.Optional

Subject: Re: [Boost-users] Usage of Boost.Optional
From: Marsh Ray (marsh_at_[hidden])
Date: 2010-11-27 19:47:11

On 10/28/2010 11:27 AM, John Dlugosz wrote:
>
> I think d.reset(in_place(args)) would do the trick, so I propose that
> as a logical missing consequence of existing features.

I was (independently) looking for this today and came across this recent 
thread. So I agree with you that it seems like natural functionality 
that is conspicuously missing.

Optional even has a construct(in_place) method, but it's protected.

I need to declare a variable but I'm not ready to construct it yet. The 
type represents an operating system resource so it doesn't have 
meaningful copy semantics and designing it differently is not possible.

Std::auto_ptr would work except there's no good reason for this to 
require a heap allocation.

Boost::optional is exactly what I want, it's just that it unnecessarily 
requires a copy for deferred initialization.

- Marsh