basic_raw_socket::async_receive_from (1 of 2 overloads)

Start an asynchronous receive.

template<
    typename MutableBufferSequence,
    typename ReadToken = DEFAULT>
DEDUCED async_receive_from(
    const MutableBufferSequence & buffers,
    endpoint_type & sender_endpoint,
    ReadToken && token = DEFAULT);

This function is used to asynchronously receive raw data. It is an initiating function for an asynchronous operation, and 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 completion handler is called.

sender_endpoint

An endpoint object that receives the endpoint of the remote sender of the data. Ownership of the sender_endpoint object is retained by the caller, which must guarantee that it is valid until the completion handler is called.

token

The completion token that will be used to produce a completion handler, which will be called when the receive completes. Potential completion tokens include use_future, use_awaitable, yield_context, or a function object with the correct completion signature. The function signature of the completion 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 completion handler will not be invoked from within this function. On immediate completion, invocation of the handler will be performed in a manner equivalent to using post.

Completion Signature

void(asio::error_code, std::size_t)

Example

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

socket.async_receive_from(
    asio::buffer(data, size), 0, sender_endpoint, 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.

Per-Operation Cancellation

On POSIX or Windows operating systems, this asynchronous operation supports cancellation for the following cancellation_type values:

cancellation_type::terminal
cancellation_type::partial
cancellation_type::total