NET_DVR_Init(); // Critical step
If dwErr is not 9, look up that code instead. Hikvision SDK requires proper initialization: hcnetsdk.dll 9 hikvision error
if (!NET_DVR_Login_V40(&struLoginInfo, &struDeviceInfo, &lUserID)) NET_DVR_Init(); // Critical step If dwErr is not
NET_DVR_USER_LOGIN_INFO struLoginInfo = 0; // Zero all members struLoginInfo.dwSize = sizeof(NET_DVR_USER_LOGIN_INFO); // Then set other fields (IP, port, username, password) &lUserID)) NET_DVR_USER_LOGIN_INFO struLoginInfo = 0