Re: [sigc] Move constructor for slots not selected

[Andrejs Hanins <andrejs hanins ubnt com>]

Thank you Kjell, I have overlooked that slot<> itself is not movable. I don't need a branch for this, can 
live without movable slots for now.

On 10/23/2015 08:48 PM, Kjell Ahlstedt wrote:
> There are move constructors and move assignment operators for sigc::slot_base and sigc::slot1<> .. 
> sigc::slot7<>, but none for sigc::slot<>. See https://bugzilla.gnome.org/show_bug.cgi?id=756484. Adding 
> them would mean adding API, which will have to wait until libsigc++ 2.7.x. Like I say in comment 4 in the 
> bug report, I can create a libsigc-2-6 branch and push the patch to the master branch now, if you want it 
> now, and is willing to use the latest code from the git repository.
>
> Kjell
>
> Den 2015-10-23 kl. 14:01, skrev Andrejs Hanins:
> > Hi,
> >
> >      I noticed that both in 2.6.1 and current trunk (cabc88f) the move constructor for the slot is not 
> > selected by the compiler (gcc 4.9 and 4.8.4 tried) even in the most trivial case. Take test_slot_move.cc 
> > unit test for example:
> >
> > sigc::slot<void,int> s2(std::move(s1));
> >
> > If you now do (bool)s1 it will evaluate to 'true'. Also s1() works and calls foo() as if s1 wasn't moved 
> > to s2. I tried to add traces to slot1 copy and move constructors and indeed only copy constructor is 
> > called, but not move. So, something is wrong here - either compiler bug (unlikely) or some code in the 
> > slot/slot_base/functor_base prevents compiler from selecting move semantics for constructor.
> >
> > BR, Andrey
> > _______________________________________________