Re: [Boost-users] BGL, swap or move graphs

Subject: Re: [Boost-users] BGL, swap or move graphs
From: Daniel Hofmann (daniel_at_[hidden])
Date: 2015-12-02 05:29:06

What about type traits, to ask the type system exactly those questions?

    using directed_graph_t = adjacency_list<>;

    is_move_constructible<directed_graph_t>();
    is_move_assignable<directed_graph_t>();

For the record, both are true.

Hope that helps,
Daniel J H

On 12/02/2015 03:47 AM, Paolo Bolzoni wrote:
> Dear list,
> 
> I am writing a program where I create a graph first and I want to put
> it inside another class instance (type T). The idea is to keep the two
> steps separated as possible.
> 
> Normally, sure-fire way was using swap. Inside the class T you create
> a default object and swap it with the real one on initialization; this
> avoids needless copies and just construct a small object.
> 
> Nowadays, it is also possible to use moveable objects to even avoid
> that object creation.
> 
> 
> This is nice and I (think I) understood it, but it is possible to do
> anything like this with boost graphs? Graphs don't model Assignable,
> so swap is not possible, and I could not find anything about being
> Moveable either.
> 
> Is there really no way to accomplish a swap or a move? I just have to
> create the graph in the beginning, and keep a reference, or pointer,
> to it?
> 
> 
> Cheers,
> Paolo
> _______________________________________________
> Boost-users mailing list
> Boost-users_at_[hidden]
> http://lists.boost.org/mailman/listinfo.cgi/boost-users
>