Quick Q: When should you prefer std::function vs. a virtual function to implement a callback? -- SO
Quick A: Using a named abstract base class makes code more tightly coupled to that specific name. Where possible, prefer using std::function which is more general and flexible.
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Pros & cons of a callback (std::function/std::bind) vs an interface (abstract class)
I'm creating a server application in C++11 using Boost.Asio. I've created a class,
Server, which takes care of accepting new connections. It's basically just:void Server::Accept() { socket_.reset(new boost::asio::ip::tcp::socket(*io_service_)); acceptor_.async_accept(*socket_, boost::bind(&Server::HandleAccept, this, boost::asio::placeholders::error)); }void Server::HandleAccept(const boost::system::error_code& error) { if (!error) { // TODO } else { TRACE_ERROR("Server::HandleAccept: Error!"); } Accept(); }I've found two ways (I'm sure there are more) to "fix" the
TODOcomment, i.e. to move the socket to wherever it should go. In my case I just want it back to the class instance that owns theServerinstance (which then wraps it in aConnectionclass and inserts it to a list).
Serverhas a parameter in its constructor:std::function<void(socket)> OnAcceptwhich is called inHandleAccept.- I create an abstract class,
IServerHandleror whatever, which has one virtual methodOnAccept.ServertakesIServerHandleras parameter in its constructor and the class instance owning the server instance extendsIServerHandlerand constructsServerwith*thisas parameter.What are the pros and cons of option 1 vs option 2? Are there any better options? I'm having the same problem in my
Connectionclass (OnConnectionClosed). Also, depending on how I decide to design the system, it might need aOnPacketReceivedandOnPacketSentcallback.
A rapid-fire "now write this using lambdas" problem-solution drill with Sumant Tambe:
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