Hi,

On Thursday 04 June 2009 06:20:07 figo.zhang wrote:
> The function video_register_device() will call the
> video_register_device_index(). In this function, firtly it will do some
> argments check , if failed,it will return a negative number such as
> -EINVAL, and then do cdev_alloc() and device_register(), if success return
> zero. so video_register_device_index() canot return a a positive number.
>
> for example, see the drivers/media/video/stk-webcam.c (line 1325):
>
> err = video_register_device(&dev->vdev, VFL_TYPE_GRABBER, -1);
>       if (err)
>               STK_ERROR("v4l registration failed\n");
>       else
>               STK_INFO("Syntek USB2.0 Camera is now controlling video device"
>                       " /dev/video%d\n", dev->vdev.num);
>
> in my opinion, it will be cleaner to do something like this:
>
> err = video_register_device(&dev->vdev, VFL_TYPE_GRABBER, -1);
>       if (err != 0)
>               STK_ERROR("v4l registration failed\n");
>       else
>               STK_INFO("Syntek USB2.0 Camera is now controlling video device"
>                       " /dev/video%d\n", dev->vdev.num);

What's the difference ? (err != 0) and (err) are identical.

Best regards,

Laurent Pinchart

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