User  |  Syst  |  Libr  |  Device  |  Files  |  Other  |  Admin  |  Head  |

---

   rtime    ( 3 )

---

---

Имя (Name)

rtime - get time from a remote machine

---

Синопсис (Synopsis)

#include <rpc/auth_des.h>

       int rtime(struct sockaddr_in *addrp, struct rpc_timeval *timep,
                 struct rpc_timeval *timeout);

---

Описание (Description)

This function uses the Time Server Protocol as described in
       RFC 868 to obtain the time from a remote machine.

       The Time Server Protocol gives the time in seconds since 00:00:00
       UTC, 1 Jan 1900, and this function subtracts the appropriate
       constant in order to convert the result to seconds since the
       Epoch, 1970-01-01 00:00:00 +0000 (UTC).

       When timeout is non-NULL, the udp/time socket (port 37) is used.
       Otherwise, the tcp/time socket (port 37) is used.

---

Возвращаемое значение (Return value)

On success, 0 is returned, and the obtained 32-bit time value is
       stored in timep->tv_sec.  In case of error -1 is returned, and
       errno is set to indicate the error.

---

Ошибки (Error)

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

       EIO    The number of returned bytes is not 4.

       ETIMEDOUT
              The waiting time as defined in timeout has expired.

---

Атрибуты (Attributes)

For an explanation of the terms used in this section, see
       attributes(7).

       ┌──────────────────────────────────────┬───────────────┬─────────┐
       │Interface                             │ Attribute     │ Value   │
       ├──────────────────────────────────────┼───────────────┼─────────┤
       │rtime()                               │ Thread safety │ MT-Safe │
       └──────────────────────────────────────┴───────────────┴─────────┘

---

Примечание (Note)

Only IPv4 is supported.

       Some in.timed versions support only TCP.  Try the example program
       with use_tcp set to 1.

---

Ошибки (баги) (Bugs)

rtime() in glibc 2.2.5 and earlier does not work properly on
       64-bit machines.

---

Примеры (Examples)

This example requires that port 37 is up and open.  You may check
       that the time 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 <stdlib.h>
       #include <errno.h>
       #include <string.h>
       #include <time.h>
       #include <rpc/auth_des.h>
       #include <netdb.h>

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

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

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

           ret = rtime(&name, &time1, use_tcp ? NULL : &timeout);
           if (ret < 0)
               perror("rtime error");
           else {
               time_t t = time1.tv_sec;
               printf("%s\n", ctime(&t));
           }

           exit(EXIT_SUCCESS);
       }

---

Смотри также (See also)

ntpdate(1), inetd(8)

---