Hi Tomasz,
On Friday 23 March 2012 12:33:24 Tomasz Stanislawski wrote:
> On 03/22/2012 12:16 PM, Laurent Pinchart wrote:
> > On Tuesday 13 March 2012 11:17:02 Tomasz Stanislawski wrote:
[snip]
> >> + case VIDIOC_EXPBUF:
> >> + {
> >> + struct v4l2_exportbuffer *p = arg;
> >> +
> >> + if (!ops->vidioc_expbuf)
> >> + break;
> >> +
> >> + ret = ops->vidioc_expbuf(file, fh, p);
> >
> > You can pass arg to ops->vidioc_expbuf() directly, there's no need to
> > create a struct v4l2_exportbuffer *p variable.
>
> No problem. I tried to follow style of other ioctls.
> Notice that adding this temporary variable provides some form of type
> checking. I mean using a proper structure for a proper callback.
It makes sure that the argument passed to video_expbuf is indeed a
v4l2_exportbuffer, but it doesn't check that the arg pointer you assign to p
points to the right type, so it's a bit pointless in my opinion.
This construct makes sense if you need to access field of the arg pointer here
before or after calling the operation.
> >> + break;
> >> + }
--
Regards,
Laurent Pinchart
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