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Re: Error C2280 with MSC15 and Uniq [message #47036 is a reply to message #47033]

Wed, 16 November 2016 23:25

mirek
Messages: 13978
Registered: November 2005

Ultimate Member

awksed wrote on Wed, 16 November 2016 03:39

I'm getting error C2280 (attempting to reference a deleted function) with MSC15 (pick() usually fixes most of these)
but there is a line in Uniq that is causing problems: PostCallback(callback1(WhenInstance, v));.

MSC15x64 compiler -Od switch

(no problem with MSC10x64)

Snippets:

class Uniq
{
// callback called when another app instance is run
//
Callback1<Vector<String> const &> WhenInstance;
}

PostCallback(callback1(WhenInstance, v));

Trouble is using callback1 here... You are trying to 'deep copy' v (because it needs to become the part of callback value), but v does not have copy... (it is 'deleted').

To pass v into callback1, you need to use 'clone' or 'pick'. Which is a bit of trouble without C++14, but in C++14 you can use lambda with explicit copy specification like:


CONSOLE_APP_MAIN
{
	Event<const Vector<int>&> h = [](const Vector<int>& x) { DUMP(x); };

	Event<> ev;

	{
		Vector<int> x = { 1, 2 };
		ev = [=, x = pick(x)] { h(x); };
	}
	
	ev();
}

(this is in current trunk, upcoming 2016 release, but should work with Callback instead of Event too).

Alternatively, using

WithDeepCopy< Vector<String> > v;

would work too, with possible perfomance hit (if v is to be big)

[Updated on: Wed, 16 November 2016 23:25]

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