162306a36Sopenharmony_ci.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later 262306a36Sopenharmony_ci.. c:namespace:: V4L 362306a36Sopenharmony_ci 462306a36Sopenharmony_ci.. _VIDIOC_OVERLAY: 562306a36Sopenharmony_ci 662306a36Sopenharmony_ci******************** 762306a36Sopenharmony_ciioctl VIDIOC_OVERLAY 862306a36Sopenharmony_ci******************** 962306a36Sopenharmony_ci 1062306a36Sopenharmony_ciName 1162306a36Sopenharmony_ci==== 1262306a36Sopenharmony_ci 1362306a36Sopenharmony_ciVIDIOC_OVERLAY - Start or stop video overlay 1462306a36Sopenharmony_ci 1562306a36Sopenharmony_ciSynopsis 1662306a36Sopenharmony_ci======== 1762306a36Sopenharmony_ci 1862306a36Sopenharmony_ci.. c:macro:: VIDIOC_OVERLAY 1962306a36Sopenharmony_ci 2062306a36Sopenharmony_ci``int ioctl(int fd, VIDIOC_OVERLAY, const int *argp)`` 2162306a36Sopenharmony_ci 2262306a36Sopenharmony_ciArguments 2362306a36Sopenharmony_ci========= 2462306a36Sopenharmony_ci 2562306a36Sopenharmony_ci``fd`` 2662306a36Sopenharmony_ci File descriptor returned by :c:func:`open()`. 2762306a36Sopenharmony_ci 2862306a36Sopenharmony_ci``argp`` 2962306a36Sopenharmony_ci Pointer to an integer. 3062306a36Sopenharmony_ci 3162306a36Sopenharmony_ciDescription 3262306a36Sopenharmony_ci=========== 3362306a36Sopenharmony_ci 3462306a36Sopenharmony_ciThis ioctl is part of the :ref:`video overlay <overlay>` I/O method. 3562306a36Sopenharmony_ciApplications call :ref:`VIDIOC_OVERLAY` to start or stop the overlay. It 3662306a36Sopenharmony_citakes a pointer to an integer which must be set to zero by the 3762306a36Sopenharmony_ciapplication to stop overlay, to one to start. 3862306a36Sopenharmony_ci 3962306a36Sopenharmony_ciDrivers do not support :ref:`VIDIOC_STREAMON` or 4062306a36Sopenharmony_ci:ref:`VIDIOC_STREAMOFF <VIDIOC_STREAMON>` with 4162306a36Sopenharmony_ci``V4L2_BUF_TYPE_VIDEO_OVERLAY``. 4262306a36Sopenharmony_ci 4362306a36Sopenharmony_ciReturn Value 4462306a36Sopenharmony_ci============ 4562306a36Sopenharmony_ci 4662306a36Sopenharmony_ciOn success 0 is returned, on error -1 and the ``errno`` variable is set 4762306a36Sopenharmony_ciappropriately. The generic error codes are described at the 4862306a36Sopenharmony_ci:ref:`Generic Error Codes <gen-errors>` chapter. 4962306a36Sopenharmony_ci 5062306a36Sopenharmony_ciEINVAL 5162306a36Sopenharmony_ci The overlay parameters have not been set up. See :ref:`overlay` 5262306a36Sopenharmony_ci for the necessary steps. 53