网络时间核对

#include <WinSock2.h>
#include <Windows.h>
#include <stdio.h>
#pragma comment (lib,"ws2_32.lib")

void SetFromTime(ULONG nlong)
{
FILETIME ft;
SYSTEMTIME st;
ZeroMemory(&st,sizeof(st));
st.wYear=1900;
st.wMonth=1;
st.wDay=1;
SystemTimeToFileTime(&st,&ft);
LONGLONG *pLong=(LONGLONG*)&ft;
*pLong+=(LONGLONG)10000000*nlong;
FileTimeToSystemTime(&ft,&st);
SetSystemTime(&st);
return ;
}

int main (void)
{
WSADATA wsaData;
WSAStartup(MAKEWORD(2,2),&wsaData);
SOCKET sock=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP);
if (sock==INVALID_SOCKET)return false;
sockaddr_in sin;
sin.sin_family=AF_INET;
sin.sin_port=htons(37);
sin.sin_addr.S_un.S_addr=inet_addr("128.138.141.172");//time.nist.gov
if (connect(sock,(SOCKADDR*)&sin,sizeof(sin))==SOCKET_ERROR)
{
printf("连接失败\n");
return false;
}
ULONG ulTime=0;
if (recv(sock,(TCHAR*)&ulTime,sizeof(ulTime),0)==SOCKET_ERROR)
{
printf("接收失败\n");
return false;
}
ULONG nlong=ntohl(ulTime);
SetFromTime(nlong);
printf("时间核对成功\n");
WSACleanup();
return 0;
}