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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
commit | 5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 (patch) | |
tree | a94efe259b9009378be6d90eb30d2b019d95c194 /Documentation/userspace-api/media/v4l/func-ioctl.rst | |
parent | Initial commit. (diff) | |
download | linux-430c2fc249ea5c0536abd21c23382884005c9093.tar.xz linux-430c2fc249ea5c0536abd21c23382884005c9093.zip |
Adding upstream version 5.10.209.upstream/5.10.209upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'Documentation/userspace-api/media/v4l/func-ioctl.rst')
-rw-r--r-- | Documentation/userspace-api/media/v4l/func-ioctl.rst | 58 |
1 files changed, 58 insertions, 0 deletions
diff --git a/Documentation/userspace-api/media/v4l/func-ioctl.rst b/Documentation/userspace-api/media/v4l/func-ioctl.rst new file mode 100644 index 000000000..f3b005094 --- /dev/null +++ b/Documentation/userspace-api/media/v4l/func-ioctl.rst @@ -0,0 +1,58 @@ +.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later +.. c:namespace:: V4L + +.. _func-ioctl: + +************ +V4L2 ioctl() +************ + +Name +==== + +v4l2-ioctl - Program a V4L2 device + +Synopsis +======== + +.. code-block:: c + + #include <sys/ioctl.h> + +``int ioctl(int fd, int request, void *argp)`` + +Arguments +========= + +``fd`` + File descriptor returned by :c:func:`open()`. + +``request`` + V4L2 ioctl request code as defined in the ``videodev2.h`` header + file, for example VIDIOC_QUERYCAP. + +``argp`` + Pointer to a function parameter, usually a structure. + +Description +=========== + +The :ref:`ioctl() <func-ioctl>` function is used to program V4L2 devices. The +argument ``fd`` must be an open file descriptor. An ioctl ``request`` +has encoded in it whether the argument is an input, output or read/write +parameter, and the size of the argument ``argp`` in bytes. Macros and +defines specifying V4L2 ioctl requests are located in the +``videodev2.h`` header file. Applications should use their own copy, not +include the version in the kernel sources on the system they compile on. +All V4L2 ioctl requests, their respective function and parameters are +specified in :ref:`user-func`. + +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 +:ref:`Generic Error Codes <gen-errors>` chapter. + +When an ioctl that takes an output or read/write parameter fails, the +parameter remains unmodified. |