Function apr_socket_opt_get 

pub unsafe extern "C" fn apr_socket_opt_get(
    sock: *mut apr_socket_t,
    opt: apr_int32_t,
    on: *mut apr_int32_t,
) -> apr_status_t

Query socket options for the specified socket @param sock The socket to query @param opt The option we would like to query. One of:

           APR_SO_DEBUG      --  turn on debugging information
           APR_SO_KEEPALIVE  --  keep connections active
           APR_SO_LINGER     --  lingers on close if data is present
           APR_SO_NONBLOCK   --  Turns blocking on/off for socket
           APR_SO_REUSEADDR  --  The rules used in validating addresses
                                 supplied to bind should allow reuse
                                 of local addresses.
           APR_SO_SNDBUF     --  Set the SendBufferSize
           APR_SO_RCVBUF     --  Set the ReceiveBufferSize
           APR_SO_DISCONNECTED -- Query the disconnected state of the socket.
                                 (Currently only used on Windows)

@param on Socket option returned on the call.