Re: [PATCH v2 0/2] MR5579: win32u: Write / read available display modes as a single binary blob.

[Rémi Bernon (＠rbernon)]

On Tue May  7 08:37:34 2024 +0000, Zhiyi Zhang wrote:
> static void add_xrandr14_mode( DEVMODEW *mode, XRRModeInfo *info, DWORD
> depth, DWORD frequency,
>                                DWORD orientation )
>                                DWORD orientation, BOOL full )
> {
>     mode->dmSize = sizeof(*mode);
>     mode->dmDriverExtra = sizeof(RRMode);
>     mode->dmDriverExtra = full ? sizeof(RRMode) : 0;
> /* Allocate space for display modes in different color depths and orientations.
>      * Store a RRMode at the end of each DEVMODEW as private driver data */
>     modes = calloc( output_info->nmode * DEPTH_COUNT * orientation_count,
>                     sizeof(*modes) + sizeof(RRMode) );
>
> The problem is that dmDriverExtra is 0 when full is FALSE, yet the
> memory for dmDriverExtra is still allocated, which means you can't use
> NEXT_DEVMODEW to iterate such a DEVMODEW array.

It's just a contiguous array you can very well write the elements the way you like as long as there's enough memory?