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+.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
+.. c:namespace:: CEC
+
+.. _cec-func-open:
+
+**********
+cec open()
+**********
+
+Name
+====
+
+cec-open - Open a cec device
+
+Synopsis
+========
+
+.. code-block:: c
+
+    #include <fcntl.h>
+
+.. c:function:: int open( const char *device_name, int flags )
+
+Arguments
+=========
+
+``device_name``
+    Device to be opened.
+
+``flags``
+    Open flags. Access mode must be ``O_RDWR``.
+
+    When the ``O_NONBLOCK`` flag is given, the
+    :ref:`CEC_RECEIVE <CEC_RECEIVE>` and :ref:`CEC_DQEVENT <CEC_DQEVENT>` ioctls
+    will return the ``EAGAIN`` error code when no message or event is available, and
+    ioctls :ref:`CEC_TRANSMIT <CEC_TRANSMIT>`,
+    :ref:`CEC_ADAP_S_PHYS_ADDR <CEC_ADAP_S_PHYS_ADDR>` and
+    :ref:`CEC_ADAP_S_LOG_ADDRS <CEC_ADAP_S_LOG_ADDRS>`
+    all return 0.
+
+    Other flags have no effect.
+
+Description
+===========
+
+To open a cec device applications call :c:func:`open()` with the
+desired device name. The function has no side effects; the device
+configuration remain unchanged.
+
+When the device is opened in read-only mode, attempts to modify its
+configuration will result in an error, and ``errno`` will be set to
+EBADF.
+
+Return Value
+============
+
+:c:func:`open()` returns the new file descriptor on success. On error,
+-1 is returned, and ``errno`` is set appropriately. Possible error codes
+include:
+
+``EACCES``
+    The requested access to the file is not allowed.
+
+``EMFILE``
+    The process already has the maximum number of files open.
+
+``ENFILE``
+    The system limit on the total number of open files has been reached.
+
+``ENOMEM``
+    Insufficient kernel memory was available.
+
+``ENXIO``
+    No device corresponding to this device special file exists.