1<html><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968"><title>snd_ctl_add_vmaster_hook</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="ch03s03.html" title="Virtual Master Control API"><link rel="prev" href="API-snd-ctl-make-virtual-master.html" title="snd_ctl_make_virtual_master"><link rel="next" href="API-snd-ctl-sync-vmaster.html" title="snd_ctl_sync_vmaster"></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_ctl_add_vmaster_hook</span></th></tr><tr><td width="20%" align="left"><a accesskey="p" href="API-snd-ctl-make-virtual-master.html">Prev</a>&#160;</td><th width="60%" align="center">Virtual Master Control API</th><td width="20%" align="right">&#160;<a accesskey="n" href="API-snd-ctl-sync-vmaster.html">Next</a></td></tr></table><hr></div><div class="refentry"><a name="API-snd-ctl-add-vmaster-hook"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>snd_ctl_add_vmaster_hook &#8212; 
2     Add a hook to a vmaster control
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_ctl_add_vmaster_hook </b>(</code></td><td>struct snd_kcontrol * <var class="pdparam">kcontrol</var>, </td></tr><tr><td>&#160;</td><td>void (*<var class="pdparam">hook</var>)
4     <code>(</code>void *private_data, int<code>)</code>, </td></tr><tr><td>&#160;</td><td>void * <var class="pdparam">private_data</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer">&#160;</div></div></div><div class="refsect1"><a name="idp1094828516"></a><h2>Arguments</h2><div class="variablelist"><dl class="variablelist"><dt><span class="term"><em class="parameter"><code>kcontrol</code></em></span></dt><dd><p>
5     vmaster kctl element
6    </p></dd><dt><span class="term"><em class="parameter"><code>hook</code></em></span></dt><dd><p>
7     the hook function
8    </p></dd><dt><span class="term"><em class="parameter"><code>private_data</code></em></span></dt><dd><p>
9     the private_data pointer to be saved
10    </p></dd></dl></div></div><div class="refsect1"><a name="idp1094832164"></a><h2>Description</h2><p>
11   Adds the given hook to the vmaster control element so that it's called
12   at each time when the value is changed.
13</p></div><div class="refsect1"><a name="idp1094832884"></a><h2>Return</h2><p>
14   Zero.
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