Berkeley description: The protocol family has not been
configured into the system or no implementation for it exists.
WinSock description: Same as Berkeley. Apparently, the
Windows Sockets specification left this out by oversight. The
WSAEAFNOSUPPORT is the likely substitute error for this in WinSock,
although its Berkeley meaning is slightly different. However, the
WSAEPROTONOSUPPORT is another possible equivalent for WinSock to use in
place of this error.
See also: WSAEAFNOSUPPORT