1.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
2
3.. _cec-func-open:
4
5**********
6cec open()
7**********
8
9Name
10====
11
12cec-open - Open a cec device
13
14Synopsis
15========
16
17.. code-block:: c
18
19    #include <fcntl.h>
20
21
22.. c:function:: int open( const char *device_name, int flags )
23   :name: cec-open
24
25
26Arguments
27=========
28
29``device_name``
30    Device to be opened.
31
32``flags``
33    Open flags. Access mode must be ``O_RDWR``.
34
35    When the ``O_NONBLOCK`` flag is given, the
36    :ref:`CEC_RECEIVE <CEC_RECEIVE>` and :ref:`CEC_DQEVENT <CEC_DQEVENT>` ioctls
37    will return the ``EAGAIN`` error code when no message or event is available, and
38    ioctls :ref:`CEC_TRANSMIT <CEC_TRANSMIT>`,
39    :ref:`CEC_ADAP_S_PHYS_ADDR <CEC_ADAP_S_PHYS_ADDR>` and
40    :ref:`CEC_ADAP_S_LOG_ADDRS <CEC_ADAP_S_LOG_ADDRS>`
41    all return 0.
42
43    Other flags have no effect.
44
45
46Description
47===========
48
49To open a cec device applications call :c:func:`open() <cec-open>` with the
50desired device name. The function has no side effects; the device
51configuration remain unchanged.
52
53When the device is opened in read-only mode, attempts to modify its
54configuration will result in an error, and ``errno`` will be set to
55EBADF.
56
57
58Return Value
59============
60
61:c:func:`open() <cec-open>` returns the new file descriptor on success. On error,
62-1 is returned, and ``errno`` is set appropriately. Possible error codes
63include:
64
65``EACCES``
66    The requested access to the file is not allowed.
67
68``EMFILE``
69    The process already has the maximum number of files open.
70
71``ENFILE``
72    The system limit on the total number of open files has been reached.
73
74``ENOMEM``
75    Insufficient kernel memory was available.
76
77``ENXIO``
78    No device corresponding to this device special file exists.
79