void __fastcall TForm1::Button1Click(TObject *Sender)
{
HINSTANCE dllInstance = LoadLibrary("url.dll");
bool (__stdcall *InetIsOffline)(int);
InetIsOffline = (bool(__stdcall*)(int))GetProcAddress(dllInstance, "InetIsOffline");
if (InetIsOffline(0))
ShowMessage("No conectado a internet");
else
ShowMessage("Conectado a internet");
FreeLibrary(dllInstance);
}