| Current File : //proc/self/root/kunden/usr/share/doc/alsa-lib-devel/doxygen/html/_2test_2pcm_min_8c-example.html |
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "https://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/xhtml;charset=UTF-8"/>
<meta http-equiv="X-UA-Compatible" content="IE=9"/>
<meta name="generator" content="Doxygen 1.9.1"/>
<meta name="viewport" content="width=device-width, initial-scale=1"/>
<title>ALSA project - the C library reference: /test/pcm_min.c</title>
<link href="tabs.css" rel="stylesheet" type="text/css"/>
<script type="text/javascript" src="jquery.js"></script>
<script type="text/javascript" src="dynsections.js"></script>
<link href="search/search.css" rel="stylesheet" type="text/css"/>
<script type="text/javascript" src="search/searchdata.js"></script>
<script type="text/javascript" src="search/search.js"></script>
<link href="doxygen.css" rel="stylesheet" type="text/css" />
</head>
<body>
<div id="top"><!-- do not remove this div, it is closed by doxygen! -->
<div id="titlearea">
<table cellspacing="0" cellpadding="0">
<tbody>
<tr style="height: 56px;">
<td id="projectalign" style="padding-left: 0.5em;">
<div id="projectname">ALSA project - the C library reference
</div>
</td>
</tr>
</tbody>
</table>
</div>
<!-- end header part -->
<!-- Generated by Doxygen 1.9.1 -->
<script type="text/javascript">
/* @license magnet:?xt=urn:btih:cf05388f2679ee054f2beb29a391d25f4e673ac3&dn=gpl-2.0.txt GPL-v2 */
var searchBox = new SearchBox("searchBox", "search",false,'Search','.html');
/* @license-end */
</script>
<script type="text/javascript" src="menudata.js"></script>
<script type="text/javascript" src="menu.js"></script>
<script type="text/javascript">
/* @license magnet:?xt=urn:btih:cf05388f2679ee054f2beb29a391d25f4e673ac3&dn=gpl-2.0.txt GPL-v2 */
$(function() {
initMenu('',true,false,'search.php','Search');
$(document).ready(function() { init_search(); });
});
/* @license-end */</script>
<div id="main-nav"></div>
</div><!-- top -->
<!-- window showing the filter options -->
<div id="MSearchSelectWindow"
onmouseover="return searchBox.OnSearchSelectShow()"
onmouseout="return searchBox.OnSearchSelectHide()"
onkeydown="return searchBox.OnSearchSelectKey(event)">
</div>
<!-- iframe showing the search results (closed by default) -->
<div id="MSearchResultsWindow">
<iframe src="javascript:void(0)" frameborder="0"
name="MSearchResults" id="MSearchResults">
</iframe>
</div>
<div class="header">
<div class="headertitle">
<div class="title">/test/pcm_min.c</div> </div>
</div><!--header-->
<div class="contents">
<p><a class="anchor" id="example_test_minimal"></a>Shows the minimal code to produce a sound.</p>
<div class="fragment"><div class="line"><span class="comment">/*</span></div>
<div class="line"><span class="comment"> * This extra small demo sends a random samples to your speakers.</span></div>
<div class="line"><span class="comment"> */</span></div>
<div class="line"> </div>
<div class="line"><span class="preprocessor">#include "../include/asoundlib.h"</span></div>
<div class="line"> </div>
<div class="line"><span class="keyword">static</span> <span class="keywordtype">char</span> *device = <span class="stringliteral">"default"</span>; <span class="comment">/* playback device */</span></div>
<div class="line"><span class="keywordtype">unsigned</span> <span class="keywordtype">char</span> buffer[16*1024]; <span class="comment">/* some random data */</span></div>
<div class="line"> </div>
<div class="line"><span class="keywordtype">int</span> main(<span class="keywordtype">void</span>)</div>
<div class="line">{</div>
<div class="line"> <span class="keywordtype">int</span> err;</div>
<div class="line"> <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> i;</div>
<div class="line"> <a class="code" href="group___p_c_m.html#ga919e634deecd855b6e2e15174e70d3ea">snd_pcm_t</a> *handle;</div>
<div class="line"> <a class="code" href="group___p_c_m.html#ga71cdfa37e258d2210b8bd0216bf0c36c">snd_pcm_sframes_t</a> frames;</div>
<div class="line"> </div>
<div class="line"> <span class="keywordflow">for</span> (i = 0; i < <span class="keyword">sizeof</span>(buffer); i++)</div>
<div class="line"> buffer[i] = random() & 0xff;</div>
<div class="line"> </div>
<div class="line"> <span class="keywordflow">if</span> ((err = <a name="a0"></a><a class="code" href="group___p_c_m.html#ga8340c7dc0ac37f37afe5e7c21d6c528b">snd_pcm_open</a>(&handle, device, <a name="a1"></a><a class="code" href="group___p_c_m.html#ggac23b43ff55add78638e503b9cc892c24a57a2b920dbc34173479fc9036cfc78a1">SND_PCM_STREAM_PLAYBACK</a>, 0)) < 0) {</div>
<div class="line"> printf(<span class="stringliteral">"Playback open error: %s\n"</span>, <a name="a2"></a><a class="code" href="group___error.html#ga182bbadf2349e11602bc531e8cf22f7e">snd_strerror</a>(err));</div>
<div class="line"> exit(EXIT_FAILURE);</div>
<div class="line"> }</div>
<div class="line"> <span class="keywordflow">if</span> ((err = <a name="a3"></a><a class="code" href="group___p_c_m.html#ga45d50841b307f2156fce1857bfac228c">snd_pcm_set_params</a>(handle,</div>
<div class="line"> <a name="a4"></a><a class="code" href="group___p_c_m.html#ggaa14b7f26877a812acbb39811364177f8ad5856f97113926836a7c6651cb8864a3">SND_PCM_FORMAT_U8</a>,</div>
<div class="line"> <a name="a5"></a><a class="code" href="group___p_c_m.html#gga661221ba5e8f1d6eaf4ab8e2da57cc1aa72a970ed6e676ab0fd9f3c3d36737e0a">SND_PCM_ACCESS_RW_INTERLEAVED</a>,</div>
<div class="line"> 1,</div>
<div class="line"> 48000,</div>
<div class="line"> 1,</div>
<div class="line"> 500000)) < 0) { <span class="comment">/* 0.5sec */</span></div>
<div class="line"> printf(<span class="stringliteral">"Playback open error: %s\n"</span>, <a class="code" href="group___error.html#ga182bbadf2349e11602bc531e8cf22f7e">snd_strerror</a>(err));</div>
<div class="line"> exit(EXIT_FAILURE);</div>
<div class="line"> }</div>
<div class="line"> </div>
<div class="line"> <span class="keywordflow">for</span> (i = 0; i < 16; i++) {</div>
<div class="line"> frames = <a name="a6"></a><a class="code" href="group___p_c_m.html#gabc748a500743713eafa960c7d104ca6f">snd_pcm_writei</a>(handle, buffer, <span class="keyword">sizeof</span>(buffer));</div>
<div class="line"> <span class="keywordflow">if</span> (frames < 0)</div>
<div class="line"> frames = <a name="a7"></a><a class="code" href="group___p_c_m.html#ga2157aaeb6fc14da3f040d76591f9d3b1">snd_pcm_recover</a>(handle, frames, 0);</div>
<div class="line"> <span class="keywordflow">if</span> (frames < 0) {</div>
<div class="line"> printf(<span class="stringliteral">"snd_pcm_writei failed: %s\n"</span>, <a class="code" href="group___error.html#ga182bbadf2349e11602bc531e8cf22f7e">snd_strerror</a>(frames));</div>
<div class="line"> <span class="keywordflow">break</span>;</div>
<div class="line"> }</div>
<div class="line"> <span class="keywordflow">if</span> (frames > 0 && frames < (<span class="keywordtype">long</span>)<span class="keyword">sizeof</span>(buffer))</div>
<div class="line"> printf(<span class="stringliteral">"Short write (expected %li, wrote %li)\n"</span>, (<span class="keywordtype">long</span>)<span class="keyword">sizeof</span>(buffer), frames);</div>
<div class="line"> }</div>
<div class="line"> </div>
<div class="line"> <span class="comment">/* pass the remaining samples, otherwise they're dropped in close */</span></div>
<div class="line"> err = <a name="a8"></a><a class="code" href="group___p_c_m.html#ga49afc5b8527f30c33fafa476533c9f86">snd_pcm_drain</a>(handle);</div>
<div class="line"> <span class="keywordflow">if</span> (err < 0)</div>
<div class="line"> printf(<span class="stringliteral">"snd_pcm_drain failed: %s\n"</span>, <a class="code" href="group___error.html#ga182bbadf2349e11602bc531e8cf22f7e">snd_strerror</a>(err));</div>
<div class="line"> <a name="a9"></a><a class="code" href="group___p_c_m.html#ga042aba7262a4cbb4d444b6fc08cb7124">snd_pcm_close</a>(handle);</div>
<div class="line"> <span class="keywordflow">return</span> 0;</div>
<div class="line">}</div>
<div class="ttc" id="agroup___error_html_ga182bbadf2349e11602bc531e8cf22f7e"><div class="ttname"><a href="group___error.html#ga182bbadf2349e11602bc531e8cf22f7e">snd_strerror</a></div><div class="ttdeci">const char * snd_strerror(int errnum)</div><div class="ttdoc">Returns the message for an error code.</div><div class="ttdef"><b>Definition:</b> error.c:51</div></div>
<div class="ttc" id="agroup___p_c_m_html_ga042aba7262a4cbb4d444b6fc08cb7124"><div class="ttname"><a href="group___p_c_m.html#ga042aba7262a4cbb4d444b6fc08cb7124">snd_pcm_close</a></div><div class="ttdeci">int snd_pcm_close(snd_pcm_t *pcm)</div><div class="ttdoc">close PCM handle</div><div class="ttdef"><b>Definition:</b> pcm.c:776</div></div>
<div class="ttc" id="agroup___p_c_m_html_ga2157aaeb6fc14da3f040d76591f9d3b1"><div class="ttname"><a href="group___p_c_m.html#ga2157aaeb6fc14da3f040d76591f9d3b1">snd_pcm_recover</a></div><div class="ttdeci">int snd_pcm_recover(snd_pcm_t *pcm, int err, int silent)</div><div class="ttdoc">Recover the stream state from an error or suspend.</div><div class="ttdef"><b>Definition:</b> pcm.c:8759</div></div>
<div class="ttc" id="agroup___p_c_m_html_ga45d50841b307f2156fce1857bfac228c"><div class="ttname"><a href="group___p_c_m.html#ga45d50841b307f2156fce1857bfac228c">snd_pcm_set_params</a></div><div class="ttdeci">int snd_pcm_set_params(snd_pcm_t *pcm, snd_pcm_format_t format, snd_pcm_access_t access, unsigned int channels, unsigned int rate, int soft_resample, unsigned int latency)</div><div class="ttdoc">Set the hardware and software parameters in a simple way.</div><div class="ttdef"><b>Definition:</b> pcm.c:8807</div></div>
<div class="ttc" id="agroup___p_c_m_html_ga49afc5b8527f30c33fafa476533c9f86"><div class="ttname"><a href="group___p_c_m.html#ga49afc5b8527f30c33fafa476533c9f86">snd_pcm_drain</a></div><div class="ttdeci">int snd_pcm_drain(snd_pcm_t *pcm)</div><div class="ttdoc">Stop a PCM preserving pending frames.</div><div class="ttdef"><b>Definition:</b> pcm.c:1358</div></div>
<div class="ttc" id="agroup___p_c_m_html_ga71cdfa37e258d2210b8bd0216bf0c36c"><div class="ttname"><a href="group___p_c_m.html#ga71cdfa37e258d2210b8bd0216bf0c36c">snd_pcm_sframes_t</a></div><div class="ttdeci">long snd_pcm_sframes_t</div><div class="ttdef"><b>Definition:</b> pcm.h:398</div></div>
<div class="ttc" id="agroup___p_c_m_html_ga8340c7dc0ac37f37afe5e7c21d6c528b"><div class="ttname"><a href="group___p_c_m.html#ga8340c7dc0ac37f37afe5e7c21d6c528b">snd_pcm_open</a></div><div class="ttdeci">int snd_pcm_open(snd_pcm_t **pcm, const char *name, snd_pcm_stream_t stream, int mode)</div><div class="ttdoc">Opens a PCM.</div><div class="ttdef"><b>Definition:</b> pcm.c:2744</div></div>
<div class="ttc" id="agroup___p_c_m_html_ga919e634deecd855b6e2e15174e70d3ea"><div class="ttname"><a href="group___p_c_m.html#ga919e634deecd855b6e2e15174e70d3ea">snd_pcm_t</a></div><div class="ttdeci">struct _snd_pcm snd_pcm_t</div><div class="ttdef"><b>Definition:</b> pcm.h:418</div></div>
<div class="ttc" id="agroup___p_c_m_html_gabc748a500743713eafa960c7d104ca6f"><div class="ttname"><a href="group___p_c_m.html#gabc748a500743713eafa960c7d104ca6f">snd_pcm_writei</a></div><div class="ttdeci">snd_pcm_sframes_t snd_pcm_writei(snd_pcm_t *pcm, const void *buffer, snd_pcm_uframes_t size)</div><div class="ttdoc">Write interleaved frames to a PCM.</div><div class="ttdef"><b>Definition:</b> pcm.c:1569</div></div>
<div class="ttc" id="agroup___p_c_m_html_gga661221ba5e8f1d6eaf4ab8e2da57cc1aa72a970ed6e676ab0fd9f3c3d36737e0a"><div class="ttname"><a href="group___p_c_m.html#gga661221ba5e8f1d6eaf4ab8e2da57cc1aa72a970ed6e676ab0fd9f3c3d36737e0a">SND_PCM_ACCESS_RW_INTERLEAVED</a></div><div class="ttdeci">@ SND_PCM_ACCESS_RW_INTERLEAVED</div><div class="ttdef"><b>Definition:</b> pcm.h:118</div></div>
<div class="ttc" id="agroup___p_c_m_html_ggaa14b7f26877a812acbb39811364177f8ad5856f97113926836a7c6651cb8864a3"><div class="ttname"><a href="group___p_c_m.html#ggaa14b7f26877a812acbb39811364177f8ad5856f97113926836a7c6651cb8864a3">SND_PCM_FORMAT_U8</a></div><div class="ttdeci">@ SND_PCM_FORMAT_U8</div><div class="ttdef"><b>Definition:</b> pcm.h:131</div></div>
<div class="ttc" id="agroup___p_c_m_html_ggac23b43ff55add78638e503b9cc892c24a57a2b920dbc34173479fc9036cfc78a1"><div class="ttname"><a href="group___p_c_m.html#ggac23b43ff55add78638e503b9cc892c24a57a2b920dbc34173479fc9036cfc78a1">SND_PCM_STREAM_PLAYBACK</a></div><div class="ttdeci">@ SND_PCM_STREAM_PLAYBACK</div><div class="ttdef"><b>Definition:</b> pcm.h:103</div></div>
</div><!-- fragment --> </div><!-- contents -->
<!-- start footer part -->
<hr class="footer"/><address class="footer"><small>
Generated by <a href="https://www.doxygen.org/index.html"><img class="footer" src="doxygen.svg" width="104" height="31" alt="doxygen"/></a> 1.9.1
</small></address>
</body>
</html>