#include <rpc/auth_des.h> int rtime(struct sockaddr_in *addrp, struct rpc_timeval *timep, struct rpc_timeval *timeout);
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.
| Interface | Attribute | Value |
| rtime() | Thread safety | MT-Safe |
Some in.timed versions support only TCP. Try the example program with use_tcp set to 1.
Libc5 uses the prototype
int rtime(struct sockaddr_in *, struct timeval *, struct timeval *);
and requires
<sys/time.h>
instead of
<rpc/auth_des.h>.
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); }