[thirdparty/man-pages.git] / man3 / rtime.3

.\" Copyright 2003 walter harms (walter.harms@informatik.uni-oldenburg.de)
.\" Distributed under GPL
.\" Modified 2003-04-04 Walter Harms
.\" <walter.harms@informatik.uni-oldenburg.de>
.\"
.\" Slightly polished, aeb, 2003-04-06
.\"
.TH RTIME 3 2003-04-04 "sunrpc" "RPC time function" 
.SH NAME
rtime \- get time from a remote machine
.SH SYNOPSIS
.sp
.B "#include <rpc/des_crypt.h>"
.sp
.BI "int rtime(struct sockaddr_in *" addrp ,
.BI "struct rpc_timeval *" timep ,
.BI "struct rpc_timeval *" timeout );
.sp
.SH DESCRIPTION
This function uses the Time Server Protocol as described in
RFC\ 868 to obtain the time from a remote machine.
.LP
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.
.LP
When
.I timeout
is non-NULL, the udp/time socket (port 37) is used.
Otherwise, the tcp/time socket (port 37) is used.
.SH "RETURN VALUE"
On success, 0 is returned, and the obtained 32-bit time value is stored in
.IR timep->tv_sec .
In case of error \-1 is returned, and
.I errno
is set appropriately.
.SH ERRORS
All errors for underlying functions (sendto, poll, recvfrom, connect, read)
can occur. Moreover:
.TP
.B EIO
The number of returned bytes is not 4.
.TP
.B ETIMEDOUT
The waiting time as defined in timeout has expired.
.SH "EXAMPLE"
This example requires that port 37 is up and open. You may check
that the time entry within
.I /etc/inetd.conf
is not commented out.
.br
The program connects to a computer called 'linux'.
Using 'localhost' does not work.
The result is the localtime of the computer 'linux'.
.sp 
.nf
#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;
}
.fi
.SH "NOTES"
Only IPV4 is supported.
.LP
Some
.I in.timed
versions only support TCP. Try the above example program with
.I use_tcp
set to 1.
.LP
Libc5 uses the prototype
.br
int rtime(struct sockaddr_in *, struct timeval *, struct timeval *);
.br
and requires
.I <sys/time.h>
instead of
.IR <rpc/auth_des.h> .

.SH "BUGS"
rtime() in glibc <= 2.2.5 does not work properly on 64bit machines.
.SH "SEE ALSO"
.BR netdate (1),
.BR ntpdate (1),
.BR rdate (1),
.BR inetd (8)
Commit	Line	Data
fea681da MK	1	.\" Copyright 2003 walter harms (walter.harms@informatik.uni-oldenburg.de)
	2	.\" Distributed under GPL
	3	.\" Modified 2003-04-04 Walter Harms
	4	.\" <walter.harms@informatik.uni-oldenburg.de>
	5	.\"
	6	.\" Slightly polished, aeb, 2003-04-06
	7	.\"
	8	.TH RTIME 3 2003-04-04 "sunrpc" "RPC time function"
	9	.SH NAME
	10	rtime \- get time from a remote machine
	11	.SH SYNOPSIS
	12	.sp
	13	.B "#include <rpc/des_crypt.h>"
	14	.sp
	15	.BI "int rtime(struct sockaddr_in *" addrp ,
	16	.BI "struct rpc_timeval *" timep ,
	17	.BI "struct rpc_timeval *" timeout );
	18	.sp
	19	.SH DESCRIPTION
	20	This function uses the Time Server Protocol as described in
331da7c3	21	RFC\ 868 to obtain the time from a remote machine.
fea681da MK	22	.LP
	23	The Time Server Protocol gives the time in seconds since midnight 1900-01-01,
	24	and this function subtracts the appropriate constant in order to
	25	convert the result to seconds since midnight 1970-01-01, the Unix epoch.
	26	.LP
	27	When
	28	.I timeout
	29	is non-NULL, the udp/time socket (port 37) is used.
	30	Otherwise, the tcp/time socket (port 37) is used.
	31	.SH "RETURN VALUE"
	32	On success, 0 is returned, and the obtained 32-bit time value is stored in
	33	.IR timep->tv_sec .
8729177b	34	In case of error \-1 is returned, and
fea681da MK	35	.I errno
	36	is set appropriately.
	37	.SH ERRORS
	38	All errors for underlying functions (sendto, poll, recvfrom, connect, read)
	39	can occur. Moreover:
	40	.TP
	41	.B EIO
	42	The number of returned bytes is not 4.
	43	.TP
	44	.B ETIMEDOUT
	45	The waiting time as defined in timeout has expired.
	46	.SH "EXAMPLE"
	47	This example requires that port 37 is up and open. You may check
	48	that the time entry within
	49	.I /etc/inetd.conf
	50	is not commented out.
	51	.br
	52	The program connects to a computer called 'linux'.
	53	Using 'localhost' does not work.
	54	The result is the localtime of the computer 'linux'.
	55	.sp
	56	.nf
	57	#include <stdio.h>
	58	#include <errno.h>
	59	#include <string.h>
	60	#include <time.h>
	61	#include <rpc/auth_des.h>
	62	#include <netdb.h>
	63
	64	int use_tcp = 0;
	65	char *servername = "linux";
	66
	67	int main() {
	68	struct sockaddr_in name;
	69	struct rpc_timeval time1 = {0,0};
	70	struct rpc_timeval timeout = {1,0};
	71	struct hostent *hent;
	72	int ret;
	73
	74	memset((char *)&name, 0, sizeof(name));
	75	sethostent(1);
	76	hent = gethostbyname(servername);
	77	memcpy((char *)&name.sin_addr, hent->h_addr, hent->h_length);
	78
	79	ret = rtime(&name, &time1, use_tcp ? NULL : &timeout);
	80	if (ret < 0)
	81	perror("rtime error");
	82	else
	83	printf("%s", ctime((time_t *)&time1.tv_sec));
	84
	85	return 0;
	86	}
	87	.fi
	88	.SH "NOTES"
	89	Only IPV4 is supported.
	90	.LP
	91	Some
	92	.I in.timed
	93	versions only support TCP. Try the above example program with
	94	.I use_tcp
	95	set to 1.
	96	.LP
	97	Libc5 uses the prototype
	98	.br
99	int rtime(struct sockaddr_in , struct timeval , struct timeval *);
100	.br
101	and requires
102	.I <sys/time.h>
103	instead of
104	.IR <rpc/auth_des.h> .
105
106	.SH "BUGS"
107	rtime() in glibc <= 2.2.5 does not work properly on 64bit machines.
108	.SH "SEE ALSO"
109	.BR netdate (1),
110	.BR ntpdate (1),
111	.BR rdate (1),
112	.BR inetd (8)