if(WSAStartup(WINSOCK_VERSION,&wsadata))
{
MessageBox(NULL,"Your system does not support WinSocket2!","Error!",MB_OK);
return -1;
}
if(wsadata.wVersion!=WINSOCK_VERSION)
{
MessageBox(NULL,"Your system does not support WinSocket2!","Error!",MB_OK);
WSACleanup();
return -2;
}