GNU/Linux man pages
Livre :
Expressions régulières,
Syntaxe et mise en oeuvre :
GNU/Linux |
CentOS 4.8 |
i386 |
 |
rtime(3) |
 |
rtime − get time from a remote machine
#include <rpc/des_crypt.h>
int rtime(struct sockaddr_in *addrp, struct rpc_timeval *timep, struct rpc_timeval *timeout);
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 midnight 1900-01-01, and this function subtracts the appropriate constant in order to convert the result to seconds since midnight 1970-01-01, the Unix epoch.
When timeout is non-NULL, the udp/time socket (port 37) is used. Otherwise, the tcp/time socket (port 37) is used.
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 appropriately.
All errors for
underlying functions (sendto, poll, recvfrom, connect, read)
can occur. Moreover:
ETIMEDOUT
The waiting time as defined in timeout has expired.
|
EIO |
The number of returned bytes is not 4. |
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 <errno.h>
#include <string.h>
#include <time.h>
#include <rpc/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 = {1,0};
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);
if (ret < 0)
perror("rtime error");
else
printf("%s", ctime((time_t
*)&time1.tv_sec));
return 0;
}
Only IPV4 is supported.
Some in.timed versions only support TCP. Try the above 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>.
rtime() in glibc <= 2.2.5 does not work properly on 64bit machines.
netdate(1), ntpdate(1), rdate(1), inetd(8)
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rtime(3) | |