[Spice-devel] [PATCH spice-gtk] main: use stable comparison function for monitors

[Hans de Goede]

Hi,

On 02/20/2013 11:35 AM, Marc-André Lureau wrote:
> If monitors are equal, compare them by their addresses, to get the
> effect of a stable sort.
> ---
>   gtk/channel-main.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/gtk/channel-main.c b/gtk/channel-main.c
> index fe57684..f86e81d 100644
> --- a/gtk/channel-main.c
> +++ b/gtk/channel-main.c
> @@ -973,8 +973,9 @@ static int monitors_cmp(const void *p1, const void *p2, gpointer user_data)
>       const VDAgentMonConfig *m2 = p2;
>       double d1 = sqrt(m1->x * m1->x + m1->y * m1->y);
>       double d2 = sqrt(m2->x * m2->x + m2->y * m2->y);
> +    int diff = d1 - d2;
>
> -    return d1 - d2;
> +    return diff == 0 ? (char*)p1 - (char*)p2 : diff;

I think that should be: "(char*)p2 - (char*)p1" So that if the
address of p2 is bigger they compare as p2 > p1, and qsort will
keep the order of the array the same for monitors with identical
coordinates.

Regards,

Hans