VC automatically synchronizes updates with the Internet Time Server

After digging for a long time in vckbase and csdn, I found some useful information and finally sorted out such a function. In this way, VC achieves time synchronization, not to mention it, you can modify the source code as needed:

 

# Include <Winsock. h> <br/> # pragma comment (Lib, "ws2_32") </P> <p> struct ntp_packet <br/>{< br/> int control_word; <br/> int root_delay; <br/> int root_dispersion; <br/> int reference_identifier; <br/>__ int64reference_timestamp; <br/>__ int64 originate_timestamp; <br/>__ int64 receive_timestamp; <br/> int transmit_timestamp_seconds; <br/> int transmit_timestamp_fractions; <br/> };

 

 

/*************************************** *******************************/<Br/> /* function Description: automatic synchronization with the time server <br/>/* parameter description: None <br/>/* return value: True is returned successfully, false is returned for failure. <br/> /******************************** **************************************** /<br/> bool updatesystime () <br/>{< br/> wordwversionrequested; <br/> wsadata; </P> <p> // initialize the version <br/> wversionrequested = makeword (1, 1); <br/> If (0! = Wsastartup (wversionrequested, & wsadata) <br/>{< br/> wsacleanup (); <br/> return false; <br/>}< br/> If (lobyte (wsadata. wversion )! = 1 | hibyte (wsadata. wversion )! = 1) <br/>{< br/> wsacleanup (); <br/> return false; <br/>}</P> <p> // this IP address is a time synchronization server address in mainland China. You can modify it by yourself <br/> socket SOC = socket (af_inet, sock_dgram, ipproto_udp); <br/> struct sockaddr_in addrsrv; <br/> addrsrv. sin_addr.s_un.s_addr = inet_addr ("210.72.145.44"); <br/> addrsrv. sin_family = af_inet; <br/> addrsrv. sin_port = htons (123); </P> <p> ntp_packet ntp_send, ntp_recv; <br/> ntp_send.control_word = htonl (0x0b000000); <br/> ntp_send.root_delay = 0; <br/> ntp_send.root_dispersion = 0; <br/> latency = 0; <br/> latency = 0; <br/> ntp_send.originate_timestamp = 0; <br/> ntp_send.receive_timestamp = 0; <br/> ntp_send.transmit_timestamp_seconds = 0; <br/> latency = 0; </P> <p> If (socket_error = sendto (SOC, (const char *) & ntp_send, sizeof (ntp_send), <br/> 0, (struct sockaddr *) & addrsrv, sizeof (addrsrv) <br/>{< br/> closesocket (SOC ); <br/> return false; <br/>}< br/> int sockaddr_size = sizeof (addrsrv); <br/> If (socket_error = recvfrom (SOC, (char *) & ntp_recv, sizeof (ntp_recv), <br/> 0, (struct sockaddr *) & addrsrv, & sockaddr_size )) <br/>{< br/> closesocket (SOC); <br/> return false; <br/>}< br/> closesocket (SOC ); <br/> wsacleanup (); </P> <p> systemtimenewtime; <br/> floatsplitseconds; <br/> structtm * lplocaltime; <br/> time_tntp_time; </P> <p> // obtain the time server time <br/> ntp_time = ntohl (ntp_recv.transmit_timestamp_seconds)-2208988800; <br/> lplocaltime = localtime (& ntp_time ); <br/> If (lplocaltime = NULL) <br/>{< br/> return false; <br/>}</P> <p> // obtain the new time <br/> newtime. wyear = lplocaltime-> maid + 1900; <br/> newtime. wmonth = lplocaltime-> tm_mon + 1; <br/> newtime. wdayofweek = lplocaltime-> tm_wday; <br/> newtime. wday = lplocaltime-> tm_mday; <br/> newtime. whour = lplocaltime-> tm_hour; <br/> newtime. wminute = lplocaltime-> tm_min; <br/> newtime. wsecond = lplocaltime-> tm_sec; </P> <p> // set the time precision <br/> splitseconds = (float) ntohl (ntp_recv.transmit_timestamp_fractions ); <br/> splitseconds = (float) 0.000000000200 * splitseconds; <br/> splitseconds = (float) 1000.0 * splitseconds; <br/> newtime. wmilliseconds = (unsigned short) splitseconds; </P> <p> // modify the local system time <br/> setlocaltime (& newtime); <br/> return true; <br/>}< br/>