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authorMauro Carvalho Chehab <mchehab@s-opensource.com>2016-07-27 16:45:04 +0300
committerMauro Carvalho Chehab <mchehab@s-opensource.com>2016-07-27 16:45:04 +0300
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Merge branch 'topic/docs-next' into v4l_for_linus
* topic/docs-next: (322 commits) [media] cx23885-cardlist.rst: add a new card [media] doc-rst: add some needed escape codes [media] doc-rst: kapi: use :c:func: instead of :cpp:func doc-rst: kernel-doc: fix a change introduced by mistake [media] v4l2-ioctl.h add debug info for struct v4l2_ioctl_ops [media] dvb_ringbuffer.h: some documentation improvements [media] v4l2-ctrls.h: fully document the header file [media] doc-rst: Fix some typedef ugly warnings [media] doc-rst: reorganize the kAPI v4l2 chapters [media] rename v4l2-framework.rst to v4l2-intro.rst [media] move V4L2 clocks to a separate .rst file [media] v4l2-fh.rst: add cross references and markups [media] v4l2-fh.rst: add fh contents from v4l2-framework.rst [media] v4l2-fh.h: add documentation for it [media] v4l2-event.rst: add cross-references and markups [media] v4l2-event.h: document all functions [media] v4l2-event.rst: add text from v4l2-framework.rst [media] v4l2-framework.rst: remove videobuf quick chapter [media] v4l2-dev: add cross-references and improve markup [media] doc-rst: move v4l2-dev doc to a separate file ...
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+.. -*- coding: utf-8; mode: rst -*-
+
+.. _VIDIOC_G_OUTPUT:
+
+**************************************
+ioctl VIDIOC_G_OUTPUT, VIDIOC_S_OUTPUT
+**************************************
+
+Name
+====
+
+VIDIOC_G_OUTPUT - VIDIOC_S_OUTPUT - Query or select the current video output
+
+
+Synopsis
+========
+
+.. cpp:function:: int ioctl( int fd, int request, int *argp )
+
+
+Arguments
+=========
+
+``fd``
+ File descriptor returned by :ref:`open() <func-open>`.
+
+``request``
+ VIDIOC_G_OUTPUT, VIDIOC_S_OUTPUT
+
+``argp``
+
+
+Description
+===========
+
+To query the current video output applications call the
+:ref:`VIDIOC_G_OUTPUT <VIDIOC_G_OUTPUT>` ioctl with a pointer to an integer where the driver
+stores the number of the output, as in the struct
+:ref:`v4l2_output <v4l2-output>` ``index`` field. This ioctl will
+fail only when there are no video outputs, returning the ``EINVAL`` error
+code.
+
+To select a video output applications store the number of the desired
+output in an integer and call the :ref:`VIDIOC_S_OUTPUT <VIDIOC_G_OUTPUT>` ioctl with a
+pointer to this integer. Side effects are possible. For example outputs
+may support different video standards, so the driver may implicitly
+switch the current standard. standard. Because of these possible side
+effects applications must select an output before querying or
+negotiating any other parameters.
+
+Information about video outputs is available using the
+:ref:`VIDIOC_ENUMOUTPUT` ioctl.
+
+
+Return Value
+============
+
+On success 0 is returned, on error -1 and the ``errno`` variable is set
+appropriately. The generic error codes are described at the
+:ref:`Generic Error Codes <gen-errors>` chapter.
+
+EINVAL
+ The number of the video output is out of bounds, or there are no
+ video outputs at all.