1<html><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968"><title>snd_pcm_lib_ioctl</title><meta name="generator" content="DocBook XSL Stylesheets V1.78.1"><link rel="home" href="index.html" title="The ALSA Driver API"><link rel="up" href="ch02.html#idp1093485324" title="PCM Core"><link rel="prev" href="API-snd-pcm-hw-param-last.html" title="snd_pcm_hw_param_last"><link rel="next" href="API-snd-pcm-period-elapsed.html" title="snd_pcm_period_elapsed"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center"><span class="phrase">snd_pcm_lib_ioctl</span></th></tr><tr><td width="20%" align="left"><a accesskey="p" href="API-snd-pcm-hw-param-last.html">Prev</a>&#160;</td><th width="60%" align="center">PCM Core</th><td width="20%" align="right">&#160;<a accesskey="n" href="API-snd-pcm-period-elapsed.html">Next</a></td></tr></table><hr></div><div class="refentry"><a name="API-snd-pcm-lib-ioctl"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>snd_pcm_lib_ioctl &#8212; 
2     a generic PCM ioctl callback
3 </p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><div class="funcsynopsis"><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">int <b class="fsfunc">snd_pcm_lib_ioctl </b>(</code></td><td>struct snd_pcm_substream * <var class="pdparam">substream</var>, </td></tr><tr><td>&#160;</td><td>unsigned int <var class="pdparam">cmd</var>, </td></tr><tr><td>&#160;</td><td>void * <var class="pdparam">arg</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer">&#160;</div></div></div><div class="refsect1"><a name="idp1093772380"></a><h2>Arguments</h2><div class="variablelist"><dl class="variablelist"><dt><span class="term"><em class="parameter"><code>substream</code></em></span></dt><dd><p>
4     the pcm substream instance
5    </p></dd><dt><span class="term"><em class="parameter"><code>cmd</code></em></span></dt><dd><p>
6     ioctl command
7    </p></dd><dt><span class="term"><em class="parameter"><code>arg</code></em></span></dt><dd><p>
8     ioctl argument
9    </p></dd></dl></div></div><div class="refsect1"><a name="idp1093775860"></a><h2>Description</h2><p>
10   Processes the generic ioctl commands for PCM.
11   Can be passed as the ioctl callback for PCM ops.
12</p></div><div class="refsect1"><a name="idp1093776548"></a><h2>Return</h2><p>
13   Zero if successful, or a negative error code on failure.
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