Seth Woolley's Man Viewer

RTIME(3)                       RPC time(1,2,n) function                      RTIME(3)



NAME
       rtime - get time(1,2,n) from a remote machine

SYNOPSIS
       #include <rpc(3,5,8)/des_crypt.h>

       int  rtime(struct sockaddr_in *addrp, struct rpc_timeval *timep, struct
       rpc_timeval *timeout(1,3x,3x cbreak));


DESCRIPTION
       This function uses the Time Server Protocol as described in(1,8) RFC 868  to
       obtain the time(1,2,n) from a remote machine.

       The  Time  Server  Protocol  gives  the  time(1,2,n) in(1,8) seconds since midnight
       1900-01-01, and this function subtracts  the  appropriate  constant  in(1,8)
       order  to  convert the result to seconds since midnight 1970-01-01, the
       Unix epoch.

       When timeout(1,3x,3x cbreak) is non-NULL, the udp/time(1,2,n) socket(2,7,n) (port 37) is used.   Oth-
       erwise, the tcp/time(1,2,n) socket(2,7,n) (port 37) is used.

RETURN VALUE
       On success, 0 is returned, and the obtained 32-bit time(1,2,n) value is stored
       in(1,8) timep->tv_sec.  In case of error(8,n) -1 is returned, and  errno  is  set(7,n,1 builtins)
       appropriately.

ERRORS
       All  errors  for underlying functions (sendto, poll, recvfrom, connect,
       read(2,n,1 builtins)) can occur. Moreover:

       EIO    The number of returned bytes is not 4.

       ETIMEDOUT
              The waiting time(1,2,n) as defined in(1,8) timeout(1,3x,3x cbreak) has expired.

EXAMPLE
       This example requires that port 37 is up and open. You may  check  that
       the time(1,2,n) entry within /etc/inetd.conf is not commented out.
       The  program  connects to a computer called 'linux'.  Using 'localhost'
       does not work.  The result is the localtime of the computer 'linux'.

       #include <stdio.h>
       #include <errno.h>
       #include <string.h>
       #include <time.h>
       #include <rpc(3,5,8)/auth_des.h>
       #include <netdb.h>

       int use_tcp = 0;
       char *servername = "linux";

       int main() {
         struct sockaddr_in name;
         struct rpc_timeval time1 = {0,0};
         struct rpc_timeval timeout(1,3x,3x cbreak) = {1,0};
         struct hostent *hent;
         int ret;

         memset((char *)&name, 0, sizeof(name));
         sethostent(1);
         hent = gethostbyname(servername);
         memcpy((char *)&name.sin_addr, hent->h_addr, hent->h_length);

         ret = rtime(&name, &time1, use_tcp ? NULL : &timeout(1,3x,3x cbreak));
         if(3,n) (ret < 0)
           perror(1,3)("rtime error(8,n)");
         else
           printf(1,3,1 builtins)("%s", ctime((time_t *)&time1.tv_sec));

         return 0;
       }

NOTES
       Only IPV4 is supported.

       Some in.timed versions only support TCP. Try the above example  program
       with use_tcp set(7,n,1 builtins) to 1.

       Libc5 uses the prototype
       int rtime(struct sockaddr_in *, struct timeval *, struct timeval *);
       and requires <sys/time.h> instead of <rpc(3,5,8)/auth_des.h>.


BUGS
       rtime() in(1,8) glibc <= 2.2.5 does not work properly on 64bit machines.

SEE ALSO
       netdate(1), ntpdate(1), rdate(1), inetd(8)



sunrpc                            2003-04-04                          RTIME(3)