Re: [PATCH] user32: Don't ignore return value of MapWindowPoints

[Nikolay Sivov]

On 10/16/2012 04:10, danielfsantos(a)att.net wrote:
> ScreenToClient should return zero if the operation fails, but is always
> returning TRUE.  This patch corrects the problem and solves a crash bug
> in Lord of the Rings Online (bug #31979)
>
> Credit for this patch goes to some one else, as yet unidentified, since
> it originally came from a closed forum for beta testers of the LoTRO
> Riders of Rohan expansion and the forum has subsequently been wiped.
> ---
>   dlls/user32/winpos.c |    3 +--
>   1 files changed, 1 insertions(+), 2 deletions(-)
>
> diff --git a/dlls/user32/winpos.c b/dlls/user32/winpos.c
> index 5a2f1f2..3855b19 100644
> --- a/dlls/user32/winpos.c
> +++ b/dlls/user32/winpos.c
> @@ -250,8 +250,7 @@ BOOL WINAPI ClientToScreen( HWND hwnd, LPPOINT lppnt )
>    */
>   BOOL WINAPI ScreenToClient( HWND hwnd, LPPOINT lppnt )
>   {
> -    MapWindowPoints( 0, hwnd, lppnt, 1 );
> -    return TRUE;
> +    return MapWindowPoints( 0, hwnd, lppnt, 1 ) != 0;
>   }

This needs a test.