7.53. ioctl VIDIOC_REMOVE_BUFS¶

7.53.1. Name¶

VIDIOC_REMOVE_BUFS - Removes buffers from a queue

7.53.2. Synopsis¶

VIDIOC_REMOVE_BUFS¶

int ioctl(int fd, VIDIOC_REMOVE_BUFS, struct v4l2_remove_buffers *argp)

7.53.3. Arguments¶

fd: File descriptor returned by open().
argp: Pointer to struct v4l2_remove_buffers.

7.53.4. Description¶

Applications can optionally call the ioctl VIDIOC_REMOVE_BUFS ioctl to remove buffers from a queue. ioctl VIDIOC_CREATE_BUFS ioctl support is mandatory to enable ioctl VIDIOC_REMOVE_BUFS. This ioctl is available if the V4L2_BUF_CAP_SUPPORTS_REMOVE_BUFS capability is set on the queue when VIDIOC_REQBUFS() or VIDIOC_CREATE_BUFS() are invoked.

type v4l2_remove_buffers¶

struct v4l2_remove_buffers¶
__u32	`index`	The starting buffer index to remove. This field is ignored if count == 0.
__u32	`count`	The number of buffers to be removed with indices ‘index’ until ‘index + count - 1’. All buffers in this range must be valid and in DEQUEUED state. ioctl VIDIOC_REMOVE_BUFS will always check the validity of type`, if it is invalid it returns ``EINVAL error code. If count is set to 0 ioctl VIDIOC_REMOVE_BUFS will do nothing and return 0.
__u32	`type`	Type of the stream or buffers, this is the same as the struct `v4l2_format` `type` field. See `v4l2_buf_type` for valid values.
__u32	`reserved`[13]	A place holder for future extensions. Drivers and applications must set the array to zero.

7.53.5. Return Value¶

On success 0 is returned, on error -1 and the errno variable is set appropriately. The generic error codes are described at the Generic Error Codes chapter. If an error occurs, no buffers will be freed and one of the error codes below will be returned:

EBUSY: File I/O is in progress. One or more of the buffers in the range index to index + count - 1 are not in DEQUEUED state.
EINVAL: One or more of the buffers in the range index to index + count - 1 do not exist in the queue. The buffer type (type field) is not valid.