1184610Salfred.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later 2189002Sed.. c:namespace:: V4L 3184610Salfred 4184610Salfred.. _VIDIOC_OVERLAY: 5184610Salfred 6184610Salfred******************** 7184610Salfredioctl VIDIOC_OVERLAY 8184610Salfred******************** 9184610Salfred 10184610SalfredName 11184610Salfred==== 12184610Salfred 13184610SalfredVIDIOC_OVERLAY - Start or stop video overlay 14184610Salfred 15184610SalfredSynopsis 16184610Salfred======== 17184610Salfred 18184610Salfred.. c:macro:: VIDIOC_OVERLAY 19184610Salfred 20184610Salfred``int ioctl(int fd, VIDIOC_OVERLAY, const int *argp)`` 21184610Salfred 22184610SalfredArguments 23184610Salfred========= 24184610Salfred 25184610Salfred``fd`` 26184610Salfred File descriptor returned by :c:func:`open()`. 27184610Salfred 28184610Salfred``argp`` 29184610Salfred Pointer to an integer. 30184610Salfred 31184610SalfredDescription 32184610Salfred=========== 33184610Salfred 34184610SalfredThis ioctl is part of the :ref:`video overlay <overlay>` I/O method. 35184610SalfredApplications call :ref:`VIDIOC_OVERLAY` to start or stop the overlay. It 36184610Salfredtakes a pointer to an integer which must be set to zero by the 37184610Salfredapplication to stop overlay, to one to start. 38184610Salfred 39184610SalfredDrivers do not support :ref:`VIDIOC_STREAMON` or 40184610Salfred:ref:`VIDIOC_STREAMOFF <VIDIOC_STREAMON>` with 41184610Salfred``V4L2_BUF_TYPE_VIDEO_OVERLAY``. 42184610Salfred 43184610SalfredReturn Value 44184610Salfred============ 45184610Salfred 46184610SalfredOn success 0 is returned, on error -1 and the ``errno`` variable is set 47184610Salfredappropriately. The generic error codes are described at the 48184610Salfred:ref:`Generic Error Codes <gen-errors>` chapter. 49184610Salfred 50184610SalfredEINVAL 51184610Salfred The overlay parameters have not been set up. See :ref:`overlay` 52184610Salfred for the necessary steps. 53184610Salfred