What is the difference between asio::tcp::socket’s async_read_some and async_receive?

I believe the two are essentially identical. The reason they provide both is to provide interfaces similar to both iostreams (which have a read_some member) and sockets (which have a receive).

As Peter Tseng pointed out, async_receive does also have an overload that accepts socket_base::message_flags, which async_read_some does not.