IP_ListenToPort -- is a wrapper for listen.
int IP_ListenToPort(int port, int backlog);
int IP_ListenToPort
A port number.
The number of connection requests that are allowed to be simultaneously pending.
The file descriptor (socket), or -1 and errno is set.
This function wraps the listen library call, and registers the resulting file descriptor with the IP_Receive function.
Working with TCP/IP, IP_ListenToService, IP_ConnectToPort