Documentation/userspace-api/media/dvb/ca-fopen.rst

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.. document under the terms of the GNU Free Documentation License,
.. Version 1.1 or any later version published by the Free Software
.. Foundation, with no Invariant Sections, no Front-Cover Texts
.. and no Back-Cover Texts. A copy of the license is included at
.. Documentation/userspace-api/media/fdl-appendix.rst.
..
.. TODO: replace it to GFDL-1.1-or-later WITH no-invariant-sections

.. _ca_fopen:

====================
Digital TV CA open()
====================

Name
----

Digital TV CA open()


Synopsis
--------

.. c:function:: int open(const char *name, int flags)
    :name: dvb-ca-open


Arguments
---------

``name``
  Name of specific Digital TV CA device.

``flags``
  A bit-wise OR of the following flags:

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    -  - ``O_RDONLY``
       - read-only access

    -  - ``O_RDWR``
       - read/write access

    -  - ``O_NONBLOCK``
       - open in non-blocking mode
         (blocking mode is the default)


Description
-----------

This system call opens a named ca device (e.g. ``/dev/dvb/adapter?/ca?``)
for subsequent use.

When an ``open()`` call has succeeded, the device will be ready for use. The
significance of blocking or non-blocking mode is described in the
documentation for functions where there is a difference. It does not
affect the semantics of the ``open()`` call itself. A device opened in
blocking mode can later be put into non-blocking mode (and vice versa)
using the ``F_SETFL`` command of the ``fcntl`` system call. This is a
standard system call, documented in the Linux manual page for fcntl.
Only one user can open the CA Device in ``O_RDWR`` mode. All other
attempts to open the device in this mode will fail, and an error code
will be returned.


Return Value
------------


On success 0 is returned.

On error -1 is returned, and the ``errno`` variable is set
appropriately.

Generic error codes are described at the
:ref:`Generic Error Codes <gen-errors>` chapter.