VC网络连接判断API

bool isConnect;
DWORD dw;
isConnect = ::IsNetworkAlive(&dw);

if(isConnect)
　　cout << "IsNetworkAlive连接" <<endl;
else
　　cout << "IsNetworkAlive未连接" <<endl;
cout<< "---------------------------------" <<endl;  

//dw和dw2标识，可判断本机是以什么方式连接网络。如：代理、拨号等

DWORD dw2;
bool ret = InternetGetConnectedState(&dw2, 0);
if (ret)
　　cout << "InternetGetConnectedState连接" <<endl;
else
　　cout << "InternetGetConnectedState未连接" <<endl;
cout<< "**********************************"  <<endl;  

//FLAG_ICC_FORCE_CONNECTION不可少；当该网络连接地址链接不通时，该API需ping一段时间(1~2分钟)
      bool bConnected = InternetCheckConnection(_T("http://www.baidu.com"), FLAG_ICC_FORCE_CONNECTION, 0);
if (bConnected)
　　cout << "InternetCheckConnection连接" <<endl;
else
　　cout << "InternetCheckConnection未连接" <<endl;
cout<< "%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%"  <<endl;