diff options
author | Jiri Kosina <jkosina@suse.cz> | 2011-04-26 10:22:15 +0200 |
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committer | Jiri Kosina <jkosina@suse.cz> | 2011-04-26 10:22:59 +0200 |
commit | 07f9479a40cc778bc1462ada11f95b01360ae4ff (patch) | |
tree | 0676cf38df3844004bb3ebfd99dfa67a4a8998f5 /Documentation/DocBook/v4l/media-func-ioctl.xml | |
parent | 9d5e6bdb3013acfb311ab407eeca0b6a6a3dedbf (diff) | |
parent | cd2e49e90f1cae7726c9a2c54488d881d7f1cd1c (diff) |
Merge branch 'master' into for-next
Fast-forwarded to current state of Linus' tree as there are patches to be
applied for files that didn't exist on the old branch.
Diffstat (limited to 'Documentation/DocBook/v4l/media-func-ioctl.xml')
-rw-r--r-- | Documentation/DocBook/v4l/media-func-ioctl.xml | 116 |
1 files changed, 116 insertions, 0 deletions
diff --git a/Documentation/DocBook/v4l/media-func-ioctl.xml b/Documentation/DocBook/v4l/media-func-ioctl.xml new file mode 100644 index 00000000000..bda8604de15 --- /dev/null +++ b/Documentation/DocBook/v4l/media-func-ioctl.xml @@ -0,0 +1,116 @@ +<refentry id="media-func-ioctl"> + <refmeta> + <refentrytitle>media ioctl()</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>media-ioctl</refname> + <refpurpose>Control a media device</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcsynopsisinfo>#include <sys/ioctl.h></funcsynopsisinfo> + <funcprototype> + <funcdef>int <function>ioctl</function></funcdef> + <paramdef>int <parameter>fd</parameter></paramdef> + <paramdef>int <parameter>request</parameter></paramdef> + <paramdef>void *<parameter>argp</parameter></paramdef> + </funcprototype> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Arguments</title> + + <variablelist> + <varlistentry> + <term><parameter>fd</parameter></term> + <listitem> + <para>&fd;</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>request</parameter></term> + <listitem> + <para>Media ioctl request code as defined in the media.h header file, + for example MEDIA_IOC_SETUP_LINK.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para>Pointer to a request-specific structure.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + <para>The <function>ioctl()</function> function manipulates media device + parameters. The argument <parameter>fd</parameter> must be an open file + descriptor.</para> + <para>The ioctl <parameter>request</parameter> code specifies the media + function to be called. It has encoded in it whether the argument is an + input, output or read/write parameter, and the size of the argument + <parameter>argp</parameter> in bytes.</para> + <para>Macros and structures definitions specifying media ioctl requests and + their parameters are located in the media.h header file. All media ioctl + requests, their respective function and parameters are specified in + <xref linkend="media-user-func" />.</para> + </refsect1> + + <refsect1> + <title>Return Value</title> + + <para><function>ioctl()</function> returns <returnvalue>0</returnvalue> on + success. On failure, <returnvalue>-1</returnvalue> is returned, and the + <varname>errno</varname> variable is set appropriately. Generic error codes + are listed below, and request-specific error codes are listed in the + individual requests descriptions.</para> + <para>When an ioctl that takes an output or read/write parameter fails, + the parameter remains unmodified.</para> + + <variablelist> + <varlistentry> + <term><errorcode>EBADF</errorcode></term> + <listitem> + <para><parameter>fd</parameter> is not a valid open file descriptor. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EFAULT</errorcode></term> + <listitem> + <para><parameter>argp</parameter> references an inaccessible memory + area.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The <parameter>request</parameter> or the data pointed to by + <parameter>argp</parameter> is not valid. This is a very common error + code, see the individual ioctl requests listed in + <xref linkend="media-user-func" /> for actual causes.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>ENOMEM</errorcode></term> + <listitem> + <para>Insufficient kernel memory was available to complete the + request.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>ENOTTY</errorcode></term> + <listitem> + <para><parameter>fd</parameter> is not associated with a character + special device.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> |