1 .. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
13 cec-ioctl - Control a cec device
20 #include <sys/ioctl.h>
22 ``int ioctl(int fd, int request, void *argp)``
28 File descriptor returned by :c:func:`open()`.
31 CEC ioctl request code as defined in the cec.h header file, for
32 example :ref:`CEC_ADAP_G_CAPS <CEC_ADAP_G_CAPS>`.
35 Pointer to a request-specific structure.
40 The :c:func:`ioctl()` function manipulates cec device parameters. The
41 argument ``fd`` must be an open file descriptor.
43 The ioctl ``request`` code specifies the cec function to be called. It
44 has encoded in it whether the argument is an input, output or read/write
45 parameter, and the size of the argument ``argp`` in bytes.
47 Macros and structures definitions specifying cec ioctl requests and
48 their parameters are located in the cec.h header file. All cec ioctl
49 requests, their respective function and parameters are specified in
55 On success 0 is returned, on error -1 and the ``errno`` variable is set
56 appropriately. The generic error codes are described at the
57 :ref:`Generic Error Codes <gen-errors>` chapter.
59 Request-specific error codes are listed in the individual requests
62 When an ioctl that takes an output or read/write parameter fails, the
63 parameter remains unmodified.