I saw some code examples to explain select() can handle multiple events at the same time as below:

FD_SET readfds;
FD_SET writefds;
FD_SET exceptfds;

FD_ZERO(&readfds);
FD_ZERO(&writefds);
FD_ZERO(&exceptfds);

FD_SET(someRandomSocket, &readfds);
FD_SET(someRandomSocket, &writefds);
FD_SET(someRandomSocket, &exceptfds);

timeval timeout;
timeout.tv_sec = ...;
timeout.tv_usec = ...;

int total = select(0, &readfds, &writefds, &exceptfds, &timeout);

if (total == -1)
{
    // error in select() itself, handle as needed...
}
else if (total == 0)
{
    // timeout, handle as needed...
}
else
{
    if (FD_ISSET(someRandomSocket, &exceptfds) )
    {
        // socket has inbound OOB data, or non-blocking connect() has failed, or some other socket error, handle as needed...
    }

    if (FD_ISSET(someRandomSocket, &readfds) )
    {
        // socket has inbound data, or has disconnected gracefully, handle as needed...
    }

    if (FD_ISSET(someRandomSocket, &writefds) )
    {
        // socket is writable, or non-blocking connect() has succeeded, handle as needed...
    }
}

However, I am wondering how about if the socket has write data and read data at the same time. How can I only get the read data or the write data from the socket?

For example, if FD_ISSET(someRandomSocket, &readfds) and FD_ISSET(someRandomSocket, &writefds) are both true at the same time, if I just want to get the read data, is it possible to also get the read data when I use recv(someRandomSocket, buf, 8192, 0)? Or if I just want to send out the write data, is it possible to also send out the write data when I use send(someRandomSocket, buf, 8192, 0)?