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

Question

What is the difference between:

• boost::asio::tcp::socket::async_read_some()
• boost::asio::tcp::socket::async_receive()
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Answer 1

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.

Answer 2

Their specification in the networking TR2 proposal (5.7.10.2 basic_stream_socket members) is identical too:

On async_receive:

Effects: Calls this->service.async_receive(this->implementation, buffers, 0, handler).

On async_read_some:

Effects: Calls this->service.async_receive(this->implementation, buffers, 0, handler).

So I guess this confirms Jerry's impression.

Answer 3

Confirming everyone here with two links:

1. https://github.com/boostorg/asio/blob/36eef63a9cf8ae609716d76ccb3906ff9769d53a/include/boost/asio/basic_stream_socket.hpp#L558
2. https://github.com/boostorg/asio/blob/36eef63a9cf8ae609716d76ccb3906ff9769d53a/include/boost/asio/basic_stream_socket.hpp#L834

The code is exactly the same. However async_receive has one overload with message_flags, which notably allows you to specify asio::socket_base::message_peek.