PVOID ValidateHwnd(HWND hwnd)
{
  DWORD ptr = (DWORD )memchr( (void*)GetWindowRect, 0xE8, 100);
  ptr += 8;
  DWORD addr = *(DWORD *)(ptr+1) + ptr + 5;
  PVOID (__fastcall * _ValidateHwnd)(HWND hwnd) = (PVOID (__fastcall*)(HWND)) addr;
  return _ValidateHwnd(hwnd);
}

// 32 bit code:
// ptr:          76F1767B
// addr:         76F16705
// 64 bit code:
// ptr:  000000007766A88D
// addr: 0000000031EAB855