a7c3a0d5f8
Right now, it mentions two SPDX headers that don't exist inside the Kernel: GFDL-1.1-or-later And an exception: no-invariant-sections While it would be trivial to add the first one, there's no way, currently, to distinguish, with SPDX, between a free and a non-free document under GFDL. Free documents with GFDL should not have invariant sections. There's an open issue at SPDX tree waiting for it to be solved. While we don't have this issue closed, let's just replace by a free-text license, and add a TODO note to remind us to revisit it later. Reviewed-by: Tomasz Figa <tfiga@chromium.org> Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
102 lines
2.9 KiB
ReStructuredText
102 lines
2.9 KiB
ReStructuredText
.. This file is dual-licensed: you can use it either under the terms
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.. of the GPL or the GFDL 1.1+ license, at your option. Note that this
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.. dual licensing only applies to this file, and not this project as a
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.. whole.
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..
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.. a) This file is free software; you can redistribute it and/or
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.. modify it under the terms of the GNU General Public License as
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.. published by the Free Software Foundation; either version 2 of
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.. the License, or (at your option) any later version.
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..
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.. This file is distributed in the hope that it will be useful,
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.. but WITHOUT ANY WARRANTY; without even the implied warranty of
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.. MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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.. GNU General Public License for more details.
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..
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.. Or, alternatively,
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..
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.. b) 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/media/uapi/fdl-appendix.rst.
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..
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.. TODO: replace it to GPL-2.0 OR GFDL-1.1-or-later WITH no-invariant-sections
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.. _request-func-poll:
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**************
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request poll()
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**************
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Name
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====
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request-poll - Wait for some event on a file descriptor
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Synopsis
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========
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.. code-block:: c
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#include <sys/poll.h>
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.. c:function:: int poll( struct pollfd *ufds, unsigned int nfds, int timeout )
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:name: request-poll
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Arguments
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=========
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``ufds``
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List of file descriptor events to be watched
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``nfds``
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Number of file descriptor events at the \*ufds array
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``timeout``
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Timeout to wait for events
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Description
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===========
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With the :c:func:`poll() <request-func-poll>` function applications can wait
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for a request to complete.
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On success :c:func:`poll() <request-func-poll>` returns the number of file
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descriptors that have been selected (that is, file descriptors for which the
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``revents`` field of the respective struct :c:type:`pollfd`
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is non-zero). Request file descriptor set the ``POLLPRI`` flag in ``revents``
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when the request was completed. When the function times out it returns
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a value of zero, on failure it returns -1 and the ``errno`` variable is
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set appropriately.
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Attempting to poll for a request that is not yet queued will
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set the ``POLLERR`` flag in ``revents``.
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Return Value
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============
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On success, :c:func:`poll() <request-func-poll>` returns the number of
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structures which have non-zero ``revents`` fields, or zero if the call
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timed out. On error -1 is returned, and the ``errno`` variable is set
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appropriately:
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``EBADF``
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One or more of the ``ufds`` members specify an invalid file
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descriptor.
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``EFAULT``
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``ufds`` references an inaccessible memory area.
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``EINTR``
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The call was interrupted by a signal.
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``EINVAL``
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The ``nfds`` value exceeds the ``RLIMIT_NOFILE`` value. Use
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``getrlimit()`` to obtain this value.
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