Using C++11 lambdas asynchronously, safely

Question

I\'ve come to C++11 from an Objective-C background, and one thing I\'m struggling to come to terms with is the different capturing semantics of C++11 lambdas vs Objective-C \"bl

Answer 1

Actually, there's one right answer to this problem. The answer has the exact same effect of binding with shared_from_this() (like when you do it with boost::asio::io_service). Think about it; what does binding with shared_from_this() do? It simple replaces this. So what prevents you from replacing this with shared_from_this() totally?

Following your example, which I updated to make the difference clearer, instead of this:

auto strongThis = shared_from_this();

doSomethingAsynchronously([strongThis, this] () {
  this->someMember_ = 42; //here, you're using `this`... that's wrong!
});

Do this:

auto strongThis = shared_from_this();

doSomethingAsynchronously([strongThis] () //notice, you're not passing `this`!
{
  strongThis->someMember_ = 42;            
});

The only cost here is that you're gonna have to prefix everything with strongThis->. But this is the most meaningful way to do it.