Re: [Boost-users] Beginner question: Why boost::signal creates another instance of the slot object ?

Subject: Re: [Boost-users] Beginner question: Why boost::signal creates another instance of the slot object ?
From: Lars Viklund (zao_at_[hidden])
Date: 2010-08-20 15:53:14

On Fri, Aug 20, 2010 at 04:25:07PM -0300, Mauricio Gomes wrote:
> > As for your initial problem of the receiver being dis-associated from
> > the callable, it's probably because it's not properly copyable
> I thought the compiler would generate a copy constructor and
> assignment operator suitable for S. Is not the case ?
> -- 
> Mau

The synthesised cctor and op= will do a member-wise copy and
assignment, respectively.

If you have value members, the copy or target will contain copies of
them.

If you want to share state between two instances, you need to have
reference members, reference_wrapper members or pointer-type members.

Like say:

struct S1
{
        shared_ptr<int> x;
};

or

struct S2
{
        boost::reference_wrapper<int> x;
};

-- 
Lars Viklund | zao_at_[hidden]