[libcamera-devel] [PATCH] v4l2: v4l2_camera_proxy: Fix sign compare compilation error

[Niklas Söderlund]

Hi Laurent,

Thanks for your work.

On 2020-03-07 23:25:28 +0200, Laurent Pinchart wrote:
> When compiling for ARM and uClibc, gcc-8.3.0 complains about comparison
> of integer expressions of different signedness:
> 
> ../../src/v4l2/v4l2_camera_proxy.cpp: In member function ‘void* V4L2CameraProxy::mmap(void*, size_t, int, int, off_t)’:
> ../../src/v4l2/v4l2_camera_proxy.cpp:88:25: error: comparison of integer expressions of different signedness: ‘unsigned int’ and ‘off_t’ {aka ‘long int’} [-Werror=sign-compare]
>   if (index * sizeimage_ != offset || length != sizeimage_) {
>       ~~~~~~~~~~~~~~~~~~~^~~~~~~~~
> 
> Fix the compilation error with a cast.
> 
> Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>

Reviewed-by: Niklas Söderlund <niklas.soderlund at ragnatech.se>

> ---
>  src/v4l2/v4l2_camera_proxy.cpp | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/src/v4l2/v4l2_camera_proxy.cpp b/src/v4l2/v4l2_camera_proxy.cpp
> index 622520479be0..b620f236499c 100644
> --- a/src/v4l2/v4l2_camera_proxy.cpp
> +++ b/src/v4l2/v4l2_camera_proxy.cpp
> @@ -85,7 +85,8 @@ void *V4L2CameraProxy::mmap(void *addr, size_t length, int prot, int flags,
>  	}
>  
>  	unsigned int index = offset / sizeimage_;
> -	if (index * sizeimage_ != offset || length != sizeimage_) {
> +	if (static_cast<off_t>(index * sizeimage_) != offset ||
> +	    length != sizeimage_) {
>  		errno = EINVAL;
>  		return MAP_FAILED;
>  	}
> -- 
> Regards,
> 
> Laurent Pinchart
> 
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-- 
Regards,
Niklas Söderlund