| .. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later |
| .. c:namespace:: MC |
| |
| .. _media-func-ioctl: |
| |
| ************* |
| media ioctl() |
| ************* |
| |
| Name |
| ==== |
| |
| media-ioctl - Control a media 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`` |
| Media ioctl request code as defined in the media.h header file, for |
| example MEDIA_IOC_SETUP_LINK. |
| |
| ``argp`` |
| Pointer to a request-specific structure. |
| |
| Description |
| =========== |
| |
| The :ref:`ioctl() <media-func-ioctl>` function manipulates media device |
| parameters. The argument ``fd`` must be an open file descriptor. |
| |
| The ioctl ``request`` code specifies the media function to be called. It |
| 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 structures definitions specifying media ioctl requests and |
| their parameters are located in the media.h header file. All media ioctl |
| requests, their respective function and parameters are specified in |
| :ref:`media-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. |
| |
| Request-specific error codes are listed in the individual requests |
| descriptions. |
| |
| When an ioctl that takes an output or read/write parameter fails, the |
| parameter remains unmodified. |
