Documentation/media/uapi/cec/cec-func-open.rst

   1 .. -*- coding: utf-8; mode: rst -*-
   2
   3 .. _cec-func-open:
   4
   5 **********
   6 cec open()
   7 **********
   8
   9 Name
  10 ====
  11
  12 cec-open - Open a cec device
  13
  14 Synopsis
  15 ========
  16
  17 .. code-block:: c
  18
  19     #include <fcntl.h>
  20
  21
  22 .. cpp:function:: int open( const char *device_name, int flags )
  23
  24
  25 Arguments
  26 =========
  27
  28 ``device_name``
  29     Device to be opened.
  30
  31 ``flags``
  32     Open flags. Access mode must be ``O_RDWR``.
  33
  34     When the ``O_NONBLOCK`` flag is given, the
  35     :ref:`CEC_RECEIVE <CEC_RECEIVE>` and :ref:`CEC_DQEVENT <CEC_DQEVENT>` ioctls
  36     will return the ``EAGAIN`` error code when no message or event is available, and
  37     ioctls :ref:`CEC_TRANSMIT <CEC_TRANSMIT>`,
  38     :ref:`CEC_ADAP_S_PHYS_ADDR <CEC_ADAP_S_PHYS_ADDR>` and
  39     :ref:`CEC_ADAP_S_LOG_ADDRS <CEC_ADAP_S_LOG_ADDRS>`
  40     all return 0.
  41
  42     Other flags have no effect.
  43
  44
  45 Description
  46 ===========
  47
  48 .. note::
  49
  50    This documents the proposed CEC API. This API is not yet finalized
  51    and is currently only available as a staging kernel module.
  52
  53 To open a cec device applications call :c:func:`open()` with the
  54 desired device name. The function has no side effects; the device
  55 configuration remain unchanged.
  56
  57 When the device is opened in read-only mode, attempts to modify its
  58 configuration will result in an error, and ``errno`` will be set to
  59 EBADF.
  60
  61
  62 Return Value
  63 ============
  64
  65 :c:func:`open()` returns the new file descriptor on success. On error,
  66 -1 is returned, and ``errno`` is set appropriately. Possible error codes
  67 include:
  68
  69 ``EACCES``
  70     The requested access to the file is not allowed.
  71
  72 ``EMFILE``
  73     The process already has the maximum number of files open.
  74
  75 ``ENFILE``
  76     The system limit on the total number of open files has been reached.
  77
  78 ``ENOMEM``
  79     Insufficient kernel memory was available.
  80
  81 ``ENXIO``
  82     No device corresponding to this device special file exists.