The «inetd» mode works well providing Xtightvnc server is launched by a real inetd superserver that actually carry input/output streams through a real TCP socket.
However, in some cases it may be usefull to carry the VNC protocol through others types of bytes streams links (e.g. a serial line, unix socket, some VPN solutions, etc.)
It is not possible with version 1.3.9: the server fails on "setsockopt(inetdSock, IPPROTO_TCP, TCP_NODELAY,...)" (See lines 102 to 106 of "Xvnc/programs/Xserver/hw/vnc/sockets.c"). The server does assume that the "inetdSock" file descriptor that is passed to it is a real TCP socket.
So, may I suggest to simply removes the "exit(1);" in case of setsockopt failure, the one just after the "rfbLogPerror("setsockopt");" (wich is rater a Warning and not an Error).