[Interest] Lambda functions not reused by connect?

[Alejandro Exojo]

El Thursday 23 April 2015, Alejandro Exojo escribió:
> Here I added a "static bool copy" that acts as a workaround to keep the
> state  across invocations.

Which is only useful for the first connect call. If you are going to use it 
multiple times is useless.

> I want the "if" block that prints "should only
> be seen once" to be called only once, but it doesn't. Is this intended? I
> suppose that since lambdas are on-the-fly classes, each signal emission
> creates a new instance of the class, instead of one instance and several
> calls to operator(). Is that so?

I've used a function object/functor instead, and yes, the copy constructor is 
called twice on the connect() call, and once more for each signal emission.

> Another way to do it would be to let the lambda disconnect itself, but it
> is  quite difficult to capture the return of connect().

Or a completely different approach, since for the general case a disconnect is 
not enough. One might need a different path in the body of the function.

I think I'll create just a small QObject subclass specific for the task, so I 
can control the intances myself, and self delete to destroy the connection, or 
whatever I need. But, man, what a pity. With the lambda function it was much 
simpler and clearer, IMHO.

-- 
Alex (a.k.a. suy) | GPG ID 0x0B8B0BC2
http://barnacity.net/ | http://disperso.net