GNU/Linux man pages
Livre :
Expressions régulières,
Syntaxe et mise en oeuvre :
GNU/Linux |
Debian 6.0.4(Squeeze) |
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rtime(3) |
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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 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.
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(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.
Only IPv4 is supported.
Some in.timed versions only support 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>.
rtime() in glibc 2.2.5 and earlier does not work properly on 64-bit machines.
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>
int use_tcp =
0;
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((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\n", ctime((time_t *)
&time1.tv_sec));
exit(EXIT_SUCCESS);
}
ntpdate(1), inetd(8)
This page is part of release 3.27 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.
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rtime(3) | |