Backlog Parameter

Windows Sockets server applications generally create a socket, and then use the listen() function on it to listen for connection requests. One of the parameters passed when calling listen() is the backlog of connection requests that the application would like Windows Sockets to queue for it. This value controls the number of unaccepted connections that can be queued. Once an application accepts a connection, it is moved out of the connection request backlog and no longer counts. The Windows Sockets 1.1 specification indicates that the maximum allowable value for a backlog is 5; however, Windows NT 3.51 accepts a backlog of up to 100, Windows NT 4.0 and Windows 2000 Server accept a backlog of 200, and Windows NT 4.0 Workstation and Windows 2000 Professional accept a backlog of 5 (which reduces memory demands).