使用BOOST ASIO在异步服务器中发送局部变量

Question

Is it propertly way of sending asynchronous local variable ? Won't it will be freed after reaching of function end ? For example :

NET3_SERVER_DISCONNECT data;
    data.mLength = 9;
    data.mPacketGroup = 3;
    data.mPacketType = 100;
    data.mType = 0xcb;
                    boost::asio::async_write(socket_, boost::asio::buffer((char*)&data, sizeof(data)),
                        boost::bind(&Connection::handle_write, shared_from_this(),
                        boost::asio::placeholders::error,
                        boost::asio::placeholders::bytes_transferred));

Thanks.

Answer 1

You are correct.

As the sending is asynchronous, the function where the local variable is defined may return before the data is actually sent, meaning the pointer to it is no longer valid. This leads to undefined behavior .

You need to either allocate the data of the heap and free it in the callback, or use some structure that free its content automatically.