[Intel-gfx] [PATCH i-g-t 2/7] Cast void * pointer used in arithmetic to uint32_t*
Arkadiusz Hiler
arkadiusz.hiler at intel.com
Tue Jul 10 13:58:49 UTC 2018
On Sat, Jul 07, 2018 at 08:22:38PM -0300, Rodrigo Siqueira wrote:
> This commit fixes the GCC warning:
>
> warning: pointer of type ‘void *’ used in arithmetic [-Wpointer-arith]
> memset(ptr + offsets[0], full_range ? 0x00 : 0x10,
> ^
> warning: pointer of type ‘void *’ used in arithmetic [-Wpointer-arith]
> memset(ptr + offsets[1], 0x80,
>
> This commit cast the ptr pointer, which is a void *, to uint32_t * in
> the pointer arithmetic operation.
This will change semantics, as according to GNU C standard[1], void
pointers have a size of 1 for all arithmetical purposes.
So you should be using uint8_t (or char) pointer instead.
[1]: http://gcc.gnu.org/onlinedocs/gcc/Pointer-Arith.html
> Signed-off-by: Rodrigo Siqueira <rodrigosiqueiramelo at gmail.com>
> ---
> lib/igt_fb.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/lib/igt_fb.c b/lib/igt_fb.c
> index ae71d967..ca905038 100644
> --- a/lib/igt_fb.c
> +++ b/lib/igt_fb.c
> @@ -410,9 +410,11 @@ static int create_bo_for_fb(int fd, int width, int height,
>
> switch (format->drm_id) {
> case DRM_FORMAT_NV12:
> - memset(ptr + offsets[0], full_range ? 0x00 : 0x10,
> + memset(((uint32_t *)ptr) + offsets[0],
> + full_range ? 0x00 : 0x10,
> calculated_stride * height);
> - memset(ptr + offsets[1], 0x80,
> + memset(((uint32_t *)ptr) + offsets[1],
> + 0x80,
> calculated_stride * height/2);
> break;
> case DRM_FORMAT_YUYV:
> --
> 2.18.0
>
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