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;- }