1.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later 2.. c:namespace:: V4L 3 4.. _VIDIOC_REMOVE_BUFS: 5 6************************ 7ioctl VIDIOC_REMOVE_BUFS 8************************ 9 10Name 11==== 12 13VIDIOC_REMOVE_BUFS - Removes buffers from a queue 14 15Synopsis 16======== 17 18.. c:macro:: VIDIOC_REMOVE_BUFS 19 20``int ioctl(int fd, VIDIOC_REMOVE_BUFS, struct v4l2_remove_buffers *argp)`` 21 22Arguments 23========= 24 25``fd`` 26 File descriptor returned by :c:func:`open()`. 27 28``argp`` 29 Pointer to struct :c:type:`v4l2_remove_buffers`. 30 31Description 32=========== 33 34Applications can optionally call the :ref:`VIDIOC_REMOVE_BUFS` ioctl to 35remove buffers from a queue. 36:ref:`VIDIOC_CREATE_BUFS` ioctl support is mandatory to enable :ref:`VIDIOC_REMOVE_BUFS`. 37This ioctl is available if the ``V4L2_BUF_CAP_SUPPORTS_REMOVE_BUFS`` capability 38is set on the queue when :c:func:`VIDIOC_REQBUFS` or :c:func:`VIDIOC_CREATE_BUFS` 39are invoked. 40 41.. c:type:: v4l2_remove_buffers 42 43.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.5cm}| 44 45.. flat-table:: struct v4l2_remove_buffers 46 :header-rows: 0 47 :stub-columns: 0 48 :widths: 1 1 2 49 50 * - __u32 51 - ``index`` 52 - The starting buffer index to remove. This field is ignored if count == 0. 53 * - __u32 54 - ``count`` 55 - The number of buffers to be removed with indices 'index' until 'index + count - 1'. 56 All buffers in this range must be valid and in DEQUEUED state. 57 :ref:`VIDIOC_REMOVE_BUFS` will always check the validity of ``type`, if it is 58 invalid it returns ``EINVAL`` error code. 59 If count is set to 0 :ref:`VIDIOC_REMOVE_BUFS` will do nothing and return 0. 60 * - __u32 61 - ``type`` 62 - Type of the stream or buffers, this is the same as the struct 63 :c:type:`v4l2_format` ``type`` field. See 64 :c:type:`v4l2_buf_type` for valid values. 65 * - __u32 66 - ``reserved``\ [13] 67 - A place holder for future extensions. Drivers and applications 68 must set the array to zero. 69 70Return Value 71============ 72 73On success 0 is returned, on error -1 and the ``errno`` variable is set 74appropriately. The generic error codes are described at the 75:ref:`Generic Error Codes <gen-errors>` chapter. If an error occurs, no 76buffers will be freed and one of the error codes below will be returned: 77 78EBUSY 79 File I/O is in progress. 80 One or more of the buffers in the range ``index`` to ``index + count - 1`` are not 81 in DEQUEUED state. 82 83EINVAL 84 One or more of the buffers in the range ``index`` to ``index + count - 1`` do not 85 exist in the queue. 86 The buffer type (``type`` field) is not valid. 87