from nx_api.h:3655
UINT nx_tcp_server_socket_listen(NX_IP *ip_ptr,
UINT port,
NX_TCP_SOCKET *socket_ptr,
UINT listen_queue_size,
VOID (*tcp_listen_callback)(NX_TCP_SOCKET *socket_ptr, UINT port));
Implemented in nxe_tcp_server_socket_listen.c:85