linux_dsm_epyc7002/Documentation/DocBook/media/v4l/media-func-open.xml
Mauro Carvalho Chehab 4266129964 [media] DocBook: Move all media docbook stuff into its own directory
This patch addresses several issues pointed by Randy Dunlap
<rdunlap@xenotime.net> at changeset ece722c:

- In the generated index.html file, "media" is listed first, but it
  should be listed in alphabetical order, not first.

- The generated files are (hidden) in .tmpmedia/

- The link from the top-level index.html file to "media" is to
  media/index.html, but the file is actually in .tmpmedia/media/index.html

- Please build docs with and without using "O=builddir" and test that.

- Would it be possible for media to have its own Makefile instead of
  merging into this one?

Due to the way cleandocs target works, I had to rename the media DocBook
to media_api, otherwise cleandocs would remove the /media directory.

Thanks-to: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2011-07-27 17:52:05 -03:00

95 lines
2.8 KiB
XML

<refentry id="media-func-open">
<refmeta>
<refentrytitle>media open()</refentrytitle>
&manvol;
</refmeta>
<refnamediv>
<refname>media-open</refname>
<refpurpose>Open a media device</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcsynopsisinfo>#include &lt;fcntl.h&gt;</funcsynopsisinfo>
<funcprototype>
<funcdef>int <function>open</function></funcdef>
<paramdef>const char *<parameter>device_name</parameter></paramdef>
<paramdef>int <parameter>flags</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>device_name</parameter></term>
<listitem>
<para>Device to be opened.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>flags</parameter></term>
<listitem>
<para>Open flags. Access mode must be either <constant>O_RDONLY</constant>
or <constant>O_RDWR</constant>. Other flags have no effect.</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>To open a media device applications call <function>open()</function>
with the desired device name. The function has no side effects; the device
configuration remain unchanged.</para>
<para>When the device is opened in read-only mode, attemps to modify its
configuration will result in an error, and <varname>errno</varname> will be
set to <errorcode>EBADF</errorcode>.</para>
</refsect1>
<refsect1>
<title>Return Value</title>
<para><function>open</function> returns the new file descriptor on success.
On error, -1 is returned, and <varname>errno</varname> is set appropriately.
Possible error codes are:</para>
<variablelist>
<varlistentry>
<term><errorcode>EACCES</errorcode></term>
<listitem>
<para>The requested access to the file is not allowed.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><errorcode>EMFILE</errorcode></term>
<listitem>
<para>The process already has the maximum number of files open.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><errorcode>ENFILE</errorcode></term>
<listitem>
<para>The system limit on the total number of open files has been
reached.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><errorcode>ENOMEM</errorcode></term>
<listitem>
<para>Insufficient kernel memory was available.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><errorcode>ENXIO</errorcode></term>
<listitem>
<para>No device corresponding to this device special file exists.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
</refentry>