get remote time
rtime() function consults the Internet Time Server
at the address pointed to by addrp and returns the
remote time in the timeval struct pointed to by
timep. Normally, the UDP protocol is used when
consulting the Time Server. The timeout argument
specifies how long the routine should wait before giving up when waiting for a
reply. If timeout is specified as
NULL, however, the routine will instead use TCP and
block until a reply is received from the time server.
rtime() function returns the value 0 if
successful; otherwise the value -1 is returned and the global variable
errno is set to indicate the error.
rtime() function is part of libtirpc.