When using Sockets, exactly when and where do I have to close them?

The documentation (of module Socket) implies that this is not necessary? However there is sClose in SocketPrim. My application is one Server who runs `listenOn' and many (short lived) clients that `connectTo'. After I run this for a while, netstat typically says

autotool@isun11:~/autotool/serial$ netstat|grep local localhost.9121 localhost.56749 32768 0 32768 0 CLOSE_WAIT localhost.56749 localhost.9121 32768 0 32768 0 FIN_WAIT_2 localhost.9121 localhost.56753 32768 0 32768 0 CLOSE_WAIT localhost.56753 localhost.9121 32768 0 32768 0 FIN_WAIT_2

If your sockets are in the form of Handles, i.e. if you used Socket.connectTo rather than the raw version in SocketPrim, then they will be closed automatically by the standard Handle finalizer mechanism. It is good practice, however, to close them as soon as you know you no longer need them (using hClose) as this will free up the resources immediately. Sockets returned from Socket.listenOn or from the low level routines in SocketPrim must be closed by hand using SocketPrim.sClose. It is probably a bug that Socket doesn't export sClose. Cheers, Simon