basic_seq_packet_socket::async_receive (2 of 2 overloads)

Start an asynchronous receive.

template<
    typename MutableBufferSequence,
    typename ReadHandler>
DEDUCED async_receive(
    const MutableBufferSequence & buffers,
    socket_base::message_flags in_flags,
    socket_base::message_flags & out_flags,
    ReadHandler && handler);

This function is used to asynchronously receive data from the sequenced data socket. The function call always returns immediately.

Parameters

buffers

One or more buffers into which the data will be received. Although the buffers object may be copied as necessary, ownership of the underlying memory blocks is retained by the caller, which must guarantee that they remain valid until the handler is called.

in_flags

Flags specifying how the receive call is to be made.

out_flags

Once the asynchronous operation completes, contains flags associated with the received data. For example, if the socket_base::message_end_of_record bit is set then the received data marks the end of a record. The caller must guarantee that the referenced variable remains valid until the handler is called.

handler

The handler to be called when the receive operation completes. Copies will be made of the handler as required. The function signature of the handler must be:

void handler(
  const asio::error_code& error, // Result of operation.
  std::size_t bytes_transferred           // Number of bytes received.
);

Regardless of whether the asynchronous operation completes immediately or not, the handler will not be invoked from within this function. Invocation of the handler will be performed in a manner equivalent to using asio::io_context::post().

Example

To receive into a single data buffer use the buffer function as follows:

socket.async_receive(
    asio::buffer(data, size),
    0, out_flags, handler);

See the buffer documentation for information on receiving into multiple buffers in one go, and how to use it with arrays, boost::array or std::vector.