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54f38fcae5
Since 2017, there is an space reserved for userspace API,
created by changeset 1d596dee38 ("docs: Create a user-space API guide").
As the media subsystem was one of the first subsystems to use
Sphinx, until this patch, we were keeping things on a separate
place.
Let's just use the new location, as having all uAPI altogether
will likely make things easier for developers.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
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2.0 KiB
ReStructuredText
85 lines
2.0 KiB
ReStructuredText
.. Permission is granted to copy, distribute and/or modify this
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.. document under the terms of the GNU Free Documentation License,
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.. Version 1.1 or any later version published by the Free Software
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.. Foundation, with no Invariant Sections, no Front-Cover Texts
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.. and no Back-Cover Texts. A copy of the license is included at
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.. Documentation/userspace-api/media/fdl-appendix.rst.
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..
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.. TODO: replace it to GFDL-1.1-or-later WITH no-invariant-sections
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.. _ca_fopen:
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====================
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Digital TV CA open()
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====================
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Name
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----
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Digital TV CA open()
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Synopsis
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--------
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.. c:function:: int open(const char *name, int flags)
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:name: dvb-ca-open
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Arguments
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---------
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``name``
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Name of specific Digital TV CA device.
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``flags``
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A bit-wise OR of the following flags:
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.. tabularcolumns:: |p{2.5cm}|p{15.0cm}|
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.. flat-table::
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:header-rows: 0
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:stub-columns: 0
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:widths: 1 16
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- - ``O_RDONLY``
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- read-only access
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- - ``O_RDWR``
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- read/write access
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- - ``O_NONBLOCK``
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- open in non-blocking mode
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(blocking mode is the default)
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Description
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-----------
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This system call opens a named ca device (e.g. ``/dev/dvb/adapter?/ca?``)
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for subsequent use.
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When an ``open()`` call has succeeded, the device will be ready for use. The
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significance of blocking or non-blocking mode is described in the
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documentation for functions where there is a difference. It does not
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affect the semantics of the ``open()`` call itself. A device opened in
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blocking mode can later be put into non-blocking mode (and vice versa)
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using the ``F_SETFL`` command of the ``fcntl`` system call. This is a
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standard system call, documented in the Linux manual page for fcntl.
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Only one user can open the CA Device in ``O_RDWR`` mode. All other
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attempts to open the device in this mode will fail, and an error code
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will be returned.
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Return Value
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------------
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On success 0 is returned.
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On error -1 is returned, and the ``errno`` variable is set
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appropriately.
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Generic error codes are described at the
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:ref:`Generic Error Codes <gen-errors>` chapter.
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