18c2ecf20Sopenharmony_ci.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later 28c2ecf20Sopenharmony_ci.. c:namespace:: V4L 38c2ecf20Sopenharmony_ci 48c2ecf20Sopenharmony_ci.. _VIDIOC_OVERLAY: 58c2ecf20Sopenharmony_ci 68c2ecf20Sopenharmony_ci******************** 78c2ecf20Sopenharmony_ciioctl VIDIOC_OVERLAY 88c2ecf20Sopenharmony_ci******************** 98c2ecf20Sopenharmony_ci 108c2ecf20Sopenharmony_ciName 118c2ecf20Sopenharmony_ci==== 128c2ecf20Sopenharmony_ci 138c2ecf20Sopenharmony_ciVIDIOC_OVERLAY - Start or stop video overlay 148c2ecf20Sopenharmony_ci 158c2ecf20Sopenharmony_ciSynopsis 168c2ecf20Sopenharmony_ci======== 178c2ecf20Sopenharmony_ci 188c2ecf20Sopenharmony_ci.. c:macro:: VIDIOC_OVERLAY 198c2ecf20Sopenharmony_ci 208c2ecf20Sopenharmony_ci``int ioctl(int fd, VIDIOC_OVERLAY, const int *argp)`` 218c2ecf20Sopenharmony_ci 228c2ecf20Sopenharmony_ciArguments 238c2ecf20Sopenharmony_ci========= 248c2ecf20Sopenharmony_ci 258c2ecf20Sopenharmony_ci``fd`` 268c2ecf20Sopenharmony_ci File descriptor returned by :c:func:`open()`. 278c2ecf20Sopenharmony_ci 288c2ecf20Sopenharmony_ci``argp`` 298c2ecf20Sopenharmony_ci Pointer to an integer. 308c2ecf20Sopenharmony_ci 318c2ecf20Sopenharmony_ciDescription 328c2ecf20Sopenharmony_ci=========== 338c2ecf20Sopenharmony_ci 348c2ecf20Sopenharmony_ciThis ioctl is part of the :ref:`video overlay <overlay>` I/O method. 358c2ecf20Sopenharmony_ciApplications call :ref:`VIDIOC_OVERLAY` to start or stop the overlay. It 368c2ecf20Sopenharmony_citakes a pointer to an integer which must be set to zero by the 378c2ecf20Sopenharmony_ciapplication to stop overlay, to one to start. 388c2ecf20Sopenharmony_ci 398c2ecf20Sopenharmony_ciDrivers do not support :ref:`VIDIOC_STREAMON` or 408c2ecf20Sopenharmony_ci:ref:`VIDIOC_STREAMOFF <VIDIOC_STREAMON>` with 418c2ecf20Sopenharmony_ci``V4L2_BUF_TYPE_VIDEO_OVERLAY``. 428c2ecf20Sopenharmony_ci 438c2ecf20Sopenharmony_ciReturn Value 448c2ecf20Sopenharmony_ci============ 458c2ecf20Sopenharmony_ci 468c2ecf20Sopenharmony_ciOn success 0 is returned, on error -1 and the ``errno`` variable is set 478c2ecf20Sopenharmony_ciappropriately. The generic error codes are described at the 488c2ecf20Sopenharmony_ci:ref:`Generic Error Codes <gen-errors>` chapter. 498c2ecf20Sopenharmony_ci 508c2ecf20Sopenharmony_ciEINVAL 518c2ecf20Sopenharmony_ci The overlay parameters have not been set up. See :ref:`overlay` 528c2ecf20Sopenharmony_ci for the necessary steps. 53