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63 lines
1.5 KiB
63 lines
1.5 KiB
.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later |
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.. c:namespace:: CEC |
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.. _cec-func-ioctl: |
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*********** |
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cec ioctl() |
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*********** |
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Name |
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==== |
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cec-ioctl - Control a cec device |
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Synopsis |
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======== |
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.. code-block:: c |
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#include <sys/ioctl.h> |
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``int ioctl(int fd, int request, void *argp)`` |
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Arguments |
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========= |
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``fd`` |
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File descriptor returned by :c:func:`open()`. |
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``request`` |
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CEC ioctl request code as defined in the cec.h header file, for |
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example :ref:`CEC_ADAP_G_CAPS <CEC_ADAP_G_CAPS>`. |
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``argp`` |
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Pointer to a request-specific structure. |
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Description |
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=========== |
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The :c:func:`ioctl()` function manipulates cec device parameters. The |
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argument ``fd`` must be an open file descriptor. |
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The ioctl ``request`` code specifies the cec function to be called. It |
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has encoded in it whether the argument is an input, output or read/write |
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parameter, and the size of the argument ``argp`` in bytes. |
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Macros and structures definitions specifying cec ioctl requests and |
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their parameters are located in the cec.h header file. All cec ioctl |
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requests, their respective function and parameters are specified in |
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:ref:`cec-user-func`. |
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Return Value |
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============ |
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On success 0 is returned, on error -1 and the ``errno`` variable is set |
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appropriately. The generic error codes are described at the |
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:ref:`Generic Error Codes <gen-errors>` chapter. |
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Request-specific error codes are listed in the individual requests |
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descriptions. |
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When an ioctl that takes an output or read/write parameter fails, the |
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parameter remains unmodified.
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