On 10/24/2012 11:33, Christian Costa wrote:

2012/10/24 Dmitry Timoshkov <dmitry@baikal.ru>

Christian Costa <titan.costa@gmail.com> wrote:

> ���BOOL WINAPI ClientToScreen( HWND hwnd, LPPOINT lppnt )
> ���{
> + ��� ���DWORD error = GetLastError();
> +
> + ��� ���if (!hwnd)
> + ��� ���{
> + ��� ��� ��� ���SetLastError( ERROR_INVALID_WINDOW_HANDLE );
> + ��� ��� ��� ���return FALSE;
> + ��� ���}
> +
> + ��� ���SetLastError( 0xdeadbeef );
> ��� ��� ���MapWindowPoints( hwnd, 0, lppnt, 1 );
> +
> + ��� ���if (GetLastError() != 0xdeadbeef)
> + ��� ��� ��� ���return FALSE;
> +
> + ��� ���SetLastError(error);
> ��� ��� ���return TRUE;
> ���}

As been said before these games with saving/restoring last error value
are broken.

Last time you said wrong so what do you mean by wrong or broken?

The only way to know if���MapWindowPoints fails is to set last error first and check it

after. If I don't restore the previous value, the tests will not pass. Of course I can

arrange the tests but hey. And I can check windows handle here as Alexandre said.

If error reporting from MapWindowPoints is not sufficient to use it somewhere else you can always move its guts to
a separate function and report failure as you want. By the way, it only fails on invalid window handles I guess, is that right?
If you need this behaviour you have a failing WIN_GetPtr() in this case. Messing with last error is not a solution obviously,
and I don't see where MapWindowPoints even sets it.