Question

In the following code:

tcp::socket socket(io_service);
tcp::endpoint ep(boost::asio::ip::address::from_string(addr), i);


socket.async_connect(ep, &connect_handler);

socket.close();

is it correct to close the socket object, or should I close it only in the connect_handler(), resort to shared_ptr to prolong the life of of the socket object?
Thanks.

Answer 1

Closing the socket isn’t much of an issue, but the socket being destructed and deallocated is. One way to deal with it is to just make sure the socket outlives the io_service where work is being done. In other words, you just make sure to not delete it until after the io_service has exited. Obviously this won’t work in every situation.

In a variety of conditions it can be difficult to impossible to tell when all work is really done on the socket when it’s active within the io_service, and ASIO doesn’t provide any mechanism to explicitly remove or disconnect the object’s callbacks so they don’t get called. So you should consider holding the connection in a shared_ptr, which will keep the connection object until the last reference inside the io_service has been released.

Meanwhile your handler functors should handle all possible errors passed in, including the connection being destroyed.