如何读取网络上另一台机器时间(模拟net time)?谢谢!

[chg]

[hcat1999]

不是很清楚，但我有一些想法。
在做网络的时候我只知道读取NTSERVER的时间，我想读另一台机器的时间应该类似。
做一个服务器端的程序（或者能否利用Win自己有关服务器的程序）解决问题。

[NowCan]

只有客户端程序就想读取另一机器的时间可能很难，我的想法和hcat1999一样，编一个服务端程序，客户程序给服务程序发指令，由服务程序读取时间，再传回来。

[wuxfBrave]

客户/服务程序,应用通讯实现最简单了

[WHQ]

给你个服务器程序的例子（有个函数没有定义，你自己补充）

/* passUDP.cpp - passiveUDP */

#include <winsock.h>

SOCKET passivesock(const char *, const char *, int);

/*---------------------------------------------------------------
* passiveUDP - create a passive socket for use in a UDP server
*---------------------------------------------------------------
*/
SOCKET
passiveUDP(const char *service)
{
return passivesock(service, "udp", 0);
}

/* end of the file passUDP.cpp */


/* passsock.cpp - passivesock */
#include <stdlib.h>
#include <string.h>
#include <winsock.h>

void errexit(const char *, ...);
u_short portbase = 0; /* port base, for test servers */

/*---------------------------------------------------------------------
* passivesock - allocate & bind a server socket using TCP or UDP
*---------------------------------------------------------------------
*/
SOCKET
passivesock(const char *service, const char *transport, int qlen)
{
struct servent *pse; /* pointer to service information entry */
struct protoent *ppe; /* pointer to protocol information entry */
struct sockaddr_in sin; /* an Internet endpoint address */
SOCKET s; /* socket descriptor */
int type; /* socket type (SOCK_STREAM, SOCK_DGRAM) */

memset(&sin, 0, sizeof(sin));
sin.sin_family = AF_INET;
sin.sin_addr.s_addr = INADDR_ANY;

/* Map service name to port number */
if( pse = getservbyname(service, transport) )
sin.sin_port = htons((u_short)atoi(pse->s_port) + portbase);
else if( (sin.sin_port = htos((u_short)atoi(service))) == 0 )
errexit("can't get \"%s\" service entry\n", service);

/* Map protocol name to protocol number */
if( ppe = getprotobyname(transport)) == 0 )
errexit("can't get \"%s\" protocol entry\n", transport);

/* Use protocol to choose a socket type */
if( strcmp(transport, "udp") == 0 )
type = SOCK_DGRAM;
else
type = SOCK_STREAM;

/* Allocate a socket */
s = socket(PF_INET, type, ppe->p_proto);
if( s == INVALID_SOCKET )
errexit("can't create socket: %d\n", GetLastError());

/* Bind the socket */
if( bind(s, (struct sockaddr*)&sin, sizeof(sin)) == SOCKET_ERROR)
errexit("can't bind to %s port: %d\n", service, GetLastError());
if( type == SOCK_STREAM && listen(s, qlen) == SOCKET_ERROR)
errexit("can't listen on %s port: %d\n", service, GetLastError());

return s;
}

/* end of the file passsock.cpp */


/* UDPtimed.cpp - main */

#include <time.h>
#include <winsock.h>

SOCKET passiveUDP(const char *);
void errexit(const char *, ...);

#define WINEPOCH 2208988800 /* Windows epoch, in UCT secs */
#define WSVERS MAKEWORD(2, 0)

/*------------------------------------------------------------------------
* main - Iterative UDP server for TIME service
*------------------------------------------------------------------------
*/
int
main(int argc, char *argv[])
{
struct sockaddr_in fsin; /* the from address of a client */
char *service = "time"; /* service name or port number */
char buf[2048]; /* "input" buffer; any size > 1 packet */
SOCKET sock; /* server socket */
time_t now; /* current time */
int alen; /* from-address length */
WSADATA wsadata;

switch( argc )
{
case 1 : break;
case 2 : service = argv[1]; break;
default : errexit("usage" UDPtimed [port]\n");
}

if( WSAStartup(WSVERS, &wsadata) )
errexit(WSAStartup failed\n");
sock = passiveUDP(service);

while( 1 )
{
alen = sizeof(fsin);
if( recvfrom(sock, buf, sizeof(buf), 0, (struct sockaddr *)&fsin, &alen) == SOCKET_ERROR )
errexit("recvfrom: error %d\n", GetLastError());
(void) time(&now);
now = htonl((u_long)(now + WINEPOCH));
(void) sendto(sock, (char *)&now, sizeof(now), 0, (struct sockaddr *)&fsin, sizeof(fsin));
}
return 1; // not reached */
}

/* end of the file UDPtimed.cpp */

[zyb]

做一个客户端/服务器的程序，通过网络通讯协议（TCP/IP、UDP等）进行通讯传送远端时间。

[blaise]

I think what you are looking for is:
NetRemoteTOD
And I think WHQ's way also works.

[blaise]

in fact,NetRemoteTOD is just the way which "net time" works on.