Start an asynchronous receive.
template< typename MutableBufferSequence, typename ReadHandler> void async_receive_from( const MutableBufferSequence & buffers, endpoint_type & sender_endpoint, ReadHandler handler);
This function is used to asynchronously receive a datagram. The function call always returns immediately.
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.
An endpoint object that receives the endpoint of the remote sender of the datagram. Ownership of the sender_endpoint object is retained by the caller, which must guarantee that it is valid until the handler is called.
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 boost::system::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 boost::asio::io_service::post().
To receive into a single data buffer use the buffer function as follows:
socket.async_receive_from( boost::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.