connection_in and connection_out

[Bob Chen]

Hi, 


I'm a newbie to openssh and was trying to read the source code recently.
Could anyone tell me why in sshd the connection_in and connection_out are the same(seems to be integer 3 in my machine).
connection_in is used in process_input(readset), and connection_out is used in process_output(writeset);
But how does it work if it tries to read and write from the same file descriptor?


/Bob