<!-- This comment will put IE 6, 7 and 8 in quirks mode -->
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://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"/>
<title>ALSA project - the C library reference: /test/pcm.c</title>
<link href="tabs.css" rel="stylesheet" type="text/css"/>
<link href="search/search.css" rel="stylesheet" type="text/css"/>
<script type="text/javaScript" src="search/search.js"></script>
<link href="doxygen.css" rel="stylesheet" type="text/css"/>
</head>
<body onload='searchBox.OnSelectItem(0);'>
<!-- Generated by Doxygen 1.6.3 -->
<script type="text/javascript"><!--
var searchBox = new SearchBox("searchBox", "search",false,'Search');
--></script>
<div class="navigation" id="top">
<div class="tabs">
<ul>
<li><a href="index.html"><span>Main Page</span></a></li>
<li><a href="pages.html"><span>Related Pages</span></a></li>
<li><a href="modules.html"><span>Modules</span></a></li>
<li><a href="annotated.html"><span>Data Structures</span></a></li>
<li><a href="files.html"><span>Files</span></a></li>
<li><a href="examples.html"><span>Examples</span></a></li>
<li>
<div id="MSearchBox" class="MSearchBoxInactive">
<img id="MSearchSelect" src="search/search.png"
onmouseover="return searchBox.OnSearchSelectShow()"
onmouseout="return searchBox.OnSearchSelectHide()"
alt=""/>
<input type="text" id="MSearchField" value="Search" accesskey="S"
onfocus="searchBox.OnSearchFieldFocus(true)"
onblur="searchBox.OnSearchFieldFocus(false)"
onkeyup="searchBox.OnSearchFieldChange(event)"/>
<a id="MSearchClose" href="javascript:searchBox.CloseResultsWindow()"><img id="MSearchCloseImg" border="0" src="search/close.png" alt=""/></a>
</div>
</li>
</ul>
</div>
</div>
<div class="contents">
<h1>/test/pcm.c</h1><div class="fragment"><pre class="fragment"><span class="comment">/*</span>
<span class="comment"> * This small demo sends a simple sinusoidal wave to your speakers.</span>
<span class="comment"> */</span>
<span class="preprocessor">#include <stdio.h></span>
<span class="preprocessor">#include <stdlib.h></span>
<span class="preprocessor">#include <string.h></span>
<span class="preprocessor">#include <sched.h></span>
<span class="preprocessor">#include <errno.h></span>
<span class="preprocessor">#include <getopt.h></span>
<span class="preprocessor">#include "../include/asoundlib.h"</span>
<span class="preprocessor">#include <sys/time.h></span>
<span class="preprocessor">#include <math.h></span>
<span class="keyword">static</span> <span class="keywordtype">char</span> *device = <span class="stringliteral">"plughw:0,0"</span>; <span class="comment">/* playback device */</span>
<span class="keyword">static</span> <a class="code" href="group___p_c_m.html#gaa14b7f26877a812acbb39811364177f8">snd_pcm_format_t</a> format = <a name="a0"></a><a class="code" href="group___p_c_m.html#ggaa14b7f26877a812acbb39811364177f8aac4470b6be81c22af0cfe528bee4a474">SND_PCM_FORMAT_S16</a>; <span class="comment">/* sample format */</span>
<span class="keyword">static</span> <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> rate = 44100; <span class="comment">/* stream rate */</span>
<span class="keyword">static</span> <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> channels = 1; <span class="comment">/* count of channels */</span>
<span class="keyword">static</span> <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> buffer_time = 500000; <span class="comment">/* ring buffer length in us */</span>
<span class="keyword">static</span> <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> period_time = 100000; <span class="comment">/* period time in us */</span>
<span class="keyword">static</span> <span class="keywordtype">double</span> freq = 440; <span class="comment">/* sinusoidal wave frequency in Hz */</span>
<span class="keyword">static</span> <span class="keywordtype">int</span> verbose = 0; <span class="comment">/* verbose flag */</span>
<span class="keyword">static</span> <span class="keywordtype">int</span> resample = 1; <span class="comment">/* enable alsa-lib resampling */</span>
<span class="keyword">static</span> <span class="keywordtype">int</span> period_event = 0; <span class="comment">/* produce poll event after each period */</span>
<span class="keyword">static</span> <a name="a1"></a><a class="code" href="group___p_c_m.html#ga71cdfa37e258d2210b8bd0216bf0c36c">snd_pcm_sframes_t</a> buffer_size;
<span class="keyword">static</span> <a class="code" href="group___p_c_m.html#ga71cdfa37e258d2210b8bd0216bf0c36c">snd_pcm_sframes_t</a> period_size;
<span class="keyword">static</span> <a name="a2"></a><a class="code" href="group___output.html#ga49729cc6454539495c1f5b6e95cd474a" title="Internal structure for an output object.">snd_output_t</a> *output = NULL;
<span class="keyword">static</span> <span class="keywordtype">void</span> generate_sine(<span class="keyword">const</span> <a name="_a3"></a><a class="code" href="structsnd__pcm__channel__area__t.html">snd_pcm_channel_area_t</a> *areas,
<a name="a4"></a><a class="code" href="group___p_c_m.html#gab01fcfe9b97382a8d3f2027c664b8b8a">snd_pcm_uframes_t</a> offset,
<span class="keywordtype">int</span> count, <span class="keywordtype">double</span> *_phase)
{
<span class="keyword">static</span> <span class="keywordtype">double</span> max_phase = 2. * M_PI;
<span class="keywordtype">double</span> phase = *_phase;
<span class="keywordtype">double</span> step = max_phase*freq/(double)rate;
<span class="keywordtype">unsigned</span> <span class="keywordtype">char</span> *samples[channels];
<span class="keywordtype">int</span> steps[channels];
<span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> chn;
<span class="keywordtype">int</span> format_bits = <a name="a5"></a><a class="code" href="group___p_c_m___helpers.html#ga8d4e07f2d68cc16f607857ed8a222a29" title="Return nominal bits per a PCM sample.">snd_pcm_format_width</a>(format);
<span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> maxval = (1 << (format_bits - 1)) - 1;
<span class="keywordtype">int</span> bps = format_bits / 8; <span class="comment">/* bytes per sample */</span>
<span class="keywordtype">int</span> phys_bps = <a name="a6"></a><a class="code" href="group___p_c_m___helpers.html#gaa3e0ff7560342e5af2b5c7bd2d63a307" title="Return bits needed to store a PCM sample.">snd_pcm_format_physical_width</a>(format) / 8;
<span class="keywordtype">int</span> big_endian = <a name="a7"></a><a class="code" href="group___p_c_m___helpers.html#ga3c0c224b8f67e73cf2447bee0110f760" title="Return endian info for a PCM sample format.">snd_pcm_format_big_endian</a>(format) == 1;
<span class="keywordtype">int</span> to_unsigned = <a name="a8"></a><a class="code" href="group___p_c_m___helpers.html#ga8cd4e3ecc963942457e3b1b6f7661a90" title="Return sign info for a PCM sample linear format.">snd_pcm_format_unsigned</a>(format) == 1;
<span class="keywordtype">int</span> is_float = (format == <a name="a9"></a><a class="code" href="group___p_c_m.html#ggaa14b7f26877a812acbb39811364177f8a083f32474a84d344e0da496470085c8f">SND_PCM_FORMAT_FLOAT_LE</a> ||
format == <a name="a10"></a><a class="code" href="group___p_c_m.html#ggaa14b7f26877a812acbb39811364177f8ab24eac408b0d2ae6b5f68ed3a7cd2d75">SND_PCM_FORMAT_FLOAT_BE</a>);
<span class="comment">/* verify and prepare the contents of areas */</span>
<span class="keywordflow">for</span> (chn = 0; chn < channels; chn++) {
<span class="keywordflow">if</span> ((areas[chn].first % 8) != 0) {
printf(<span class="stringliteral">"areas[%i].first == %i, aborting...\n"</span>, chn, areas[chn].first);
exit(EXIT_FAILURE);
}
samples[chn] = <span class="comment">/*(signed short *)*/</span>(((<span class="keywordtype">unsigned</span> <span class="keywordtype">char</span> *)areas[chn].addr) + (areas[chn].<a name="a11"></a><a class="code" href="structsnd__pcm__channel__area__t.html#aba2a69e0d221beaa9f2f115254cb515a">first</a> / 8));
<span class="keywordflow">if</span> ((areas[chn].step % 16) != 0) {
printf(<span class="stringliteral">"areas[%i].step == %i, aborting...\n"</span>, chn, areas[chn].step);
exit(EXIT_FAILURE);
}
steps[chn] = areas[chn].<a name="a12"></a><a class="code" href="structsnd__pcm__channel__area__t.html#aedbe57a917a0ba24bf1f526387e6e43a">step</a> / 8;
samples[chn] += offset * steps[chn];
}
<span class="comment">/* fill the channel areas */</span>
<span class="keywordflow">while</span> (count-- > 0) {
<span class="keyword">union </span>{
<span class="keywordtype">float</span> f;
<span class="keywordtype">int</span> i;
} fval;
<span class="keywordtype">int</span> res, i;
<span class="keywordflow">if</span> (is_float) {
fval.f = sin(phase) * maxval;
res = fval.i;
} <span class="keywordflow">else</span>
res = sin(phase) * maxval;
<span class="keywordflow">if</span> (to_unsigned)
res ^= 1U << (format_bits - 1);
<span class="keywordflow">for</span> (chn = 0; chn < channels; chn++) {
<span class="comment">/* Generate data in native endian format */</span>
<span class="keywordflow">if</span> (big_endian) {
<span class="keywordflow">for</span> (i = 0; i < bps; i++)
*(samples[chn] + phys_bps - 1 - i) = (res >> i * 8) & 0xff;
} <span class="keywordflow">else</span> {
<span class="keywordflow">for</span> (i = 0; i < bps; i++)
*(samples[chn] + i) = (res >> i * 8) & 0xff;
}
samples[chn] += steps[chn];
}
phase += step;
<span class="keywordflow">if</span> (phase >= max_phase)
phase -= max_phase;
}
*_phase = phase;
}
<span class="keyword">static</span> <span class="keywordtype">int</span> set_hwparams(<a name="a13"></a><a class="code" href="group___p_c_m.html#ga919e634deecd855b6e2e15174e70d3ea">snd_pcm_t</a> *handle,
<a name="a14"></a><a class="code" href="group___p_c_m.html#ga65c737127994f0a980edad744e36dc40">snd_pcm_hw_params_t</a> *params,
<a class="code" href="group___p_c_m.html#ga661221ba5e8f1d6eaf4ab8e2da57cc1a">snd_pcm_access_t</a> access)
{
<span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> rrate;
<a class="code" href="group___p_c_m.html#gab01fcfe9b97382a8d3f2027c664b8b8a">snd_pcm_uframes_t</a> size;
<span class="keywordtype">int</span> err, dir;
<span class="comment">/* choose all parameters */</span>
err = <a name="a15"></a><a class="code" href="group___p_c_m___h_w___params.html#ga6e2dd8efbb7a4084bd05e6cc458d84f7" title="Fill params with a full configuration space for a PCM.">snd_pcm_hw_params_any</a>(handle, params);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"Broken configuration for playback: no configurations available: %s\n"</span>, <a name="a16"></a><a class="code" href="group___error.html#ga182bbadf2349e11602bc531e8cf22f7e" title="Returns the message for an error code.">snd_strerror</a>(err));
<span class="keywordflow">return</span> err;
}
<span class="comment">/* set hardware resampling */</span>
err = <a name="a17"></a><a class="code" href="group___p_c_m___h_w___params.html#ga82eecc0e27a94ce0caa195cc3765536c" title="Restrict a configuration space to contain only real hardware rates.">snd_pcm_hw_params_set_rate_resample</a>(handle, params, resample);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"Resampling setup failed for playback: %s\n"</span>, <a class="code" href="group___error.html#ga182bbadf2349e11602bc531e8cf22f7e" title="Returns the message for an error code.">snd_strerror</a>(err));
<span class="keywordflow">return</span> err;
}
<span class="comment">/* set the interleaved read/write format */</span>
err = <a name="a18"></a><a class="code" href="group___p_c_m___h_w___params.html#ga4c8f1c632931923531ca68ee048a8de8" title="Restrict a configuration space to contain only one access type.">snd_pcm_hw_params_set_access</a>(handle, params, access);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"Access type not available for playback: %s\n"</span>, <a class="code" href="group___error.html#ga182bbadf2349e11602bc531e8cf22f7e" title="Returns the message for an error code.">snd_strerror</a>(err));
<span class="keywordflow">return</span> err;
}
<span class="comment">/* set the sample format */</span>
err = <a name="a19"></a><a class="code" href="group___p_c_m___h_w___params.html#ga6014e0e1ec7934f8c745290e83e59199" title="Restrict a configuration space to contain only one format.">snd_pcm_hw_params_set_format</a>(handle, params, format);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"Sample format not available for playback: %s\n"</span>, <a class="code" href="group___error.html#ga182bbadf2349e11602bc531e8cf22f7e" title="Returns the message for an error code.">snd_strerror</a>(err));
<span class="keywordflow">return</span> err;
}
<span class="comment">/* set the count of channels */</span>
err = <a name="a20"></a><a class="code" href="group___p_c_m___h_w___params.html#ga3a5b2a05c5d9869cc743dac71c0d270a" title="Restrict a configuration space to contain only one channels count.">snd_pcm_hw_params_set_channels</a>(handle, params, channels);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"Channels count (%i) not available for playbacks: %s\n"</span>, channels, <a class="code" href="group___error.html#ga182bbadf2349e11602bc531e8cf22f7e" title="Returns the message for an error code.">snd_strerror</a>(err));
<span class="keywordflow">return</span> err;
}
<span class="comment">/* set the stream rate */</span>
rrate = rate;
err = <a name="a21"></a><a class="code" href="group___p_c_m___h_w___params.html#ga39124280d06ce63092a77e3f25ddd6ee" title="Restrict a configuration space to have rate nearest to a target.">snd_pcm_hw_params_set_rate_near</a>(handle, params, &rrate, 0);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"Rate %iHz not available for playback: %s\n"</span>, rate, <a class="code" href="group___error.html#ga182bbadf2349e11602bc531e8cf22f7e" title="Returns the message for an error code.">snd_strerror</a>(err));
<span class="keywordflow">return</span> err;
}
<span class="keywordflow">if</span> (rrate != rate) {
printf(<span class="stringliteral">"Rate doesn't match (requested %iHz, get %iHz)\n"</span>, rate, err);
<span class="keywordflow">return</span> -EINVAL;
}
<span class="comment">/* set the buffer time */</span>
err = <a name="a22"></a><a class="code" href="group___p_c_m___h_w___params.html#ga3bc1b188576d6d2daae9c56024813d10" title="Restrict a configuration space to have buffer time nearest to a target.">snd_pcm_hw_params_set_buffer_time_near</a>(handle, params, &buffer_time, &dir);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"Unable to set buffer time %i for playback: %s\n"</span>, buffer_time, <a class="code" href="group___error.html#ga182bbadf2349e11602bc531e8cf22f7e" title="Returns the message for an error code.">snd_strerror</a>(err));
<span class="keywordflow">return</span> err;
}
err = <a name="a23"></a><a class="code" href="group___p_c_m___h_w___params.html#gab6556fcaaf926360d2064044a6f6cfb4" title="Extract buffer size from a configuration space.">snd_pcm_hw_params_get_buffer_size</a>(params, &size);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"Unable to get buffer size for playback: %s\n"</span>, <a class="code" href="group___error.html#ga182bbadf2349e11602bc531e8cf22f7e" title="Returns the message for an error code.">snd_strerror</a>(err));
<span class="keywordflow">return</span> err;
}
buffer_size = size;
<span class="comment">/* set the period time */</span>
err = <a name="a24"></a><a class="code" href="group___p_c_m___h_w___params.html#gaa22d4f917c300b0c1f47b348c23705a4" title="Restrict a configuration space to have period time nearest to a target.">snd_pcm_hw_params_set_period_time_near</a>(handle, params, &period_time, &dir);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"Unable to set period time %i for playback: %s\n"</span>, period_time, <a class="code" href="group___error.html#ga182bbadf2349e11602bc531e8cf22f7e" title="Returns the message for an error code.">snd_strerror</a>(err));
<span class="keywordflow">return</span> err;
}
err = <a name="a25"></a><a class="code" href="group___p_c_m___h_w___params.html#gaba48ea189171536f9793e0d99e6db5e0" title="Extract period size from a configuration space.">snd_pcm_hw_params_get_period_size</a>(params, &size, &dir);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"Unable to get period size for playback: %s\n"</span>, <a class="code" href="group___error.html#ga182bbadf2349e11602bc531e8cf22f7e" title="Returns the message for an error code.">snd_strerror</a>(err));
<span class="keywordflow">return</span> err;
}
period_size = size;
<span class="comment">/* write the parameters to device */</span>
err = <a name="a26"></a><a class="code" href="group___p_c_m.html#ga1ca0dc120a484965e26cabf966502330" title="Install one PCM hardware configuration chosen from a configuration space and snd_pcm_prepare...">snd_pcm_hw_params</a>(handle, params);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"Unable to set hw params for playback: %s\n"</span>, <a class="code" href="group___error.html#ga182bbadf2349e11602bc531e8cf22f7e" title="Returns the message for an error code.">snd_strerror</a>(err));
<span class="keywordflow">return</span> err;
}
<span class="keywordflow">return</span> 0;
}
<span class="keyword">static</span> <span class="keywordtype">int</span> set_swparams(<a class="code" href="group___p_c_m.html#ga919e634deecd855b6e2e15174e70d3ea">snd_pcm_t</a> *handle, <a name="a27"></a><a class="code" href="group___p_c_m.html#ga7e082d9ea701709270b0674a0be23b09">snd_pcm_sw_params_t</a> *swparams)
{
<span class="keywordtype">int</span> err;
<span class="comment">/* get the current swparams */</span>
err = <a name="a28"></a><a class="code" href="group___p_c_m.html#ga61c5495ffb44c75aaa595e85512d28de" title="Return current software configuration for a PCM.">snd_pcm_sw_params_current</a>(handle, swparams);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"Unable to determine current swparams for playback: %s\n"</span>, <a class="code" href="group___error.html#ga182bbadf2349e11602bc531e8cf22f7e" title="Returns the message for an error code.">snd_strerror</a>(err));
<span class="keywordflow">return</span> err;
}
<span class="comment">/* start the transfer when the buffer is almost full: */</span>
<span class="comment">/* (buffer_size / avail_min) * avail_min */</span>
err = <a name="a29"></a><a class="code" href="group___p_c_m___s_w___params.html#ga1d338f1f7e33b7a6d0f9a8f61f87f057" title="Set start threshold inside a software configuration container.">snd_pcm_sw_params_set_start_threshold</a>(handle, swparams, (buffer_size / period_size) * period_size);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"Unable to set start threshold mode for playback: %s\n"</span>, <a class="code" href="group___error.html#ga182bbadf2349e11602bc531e8cf22f7e" title="Returns the message for an error code.">snd_strerror</a>(err));
<span class="keywordflow">return</span> err;
}
<span class="comment">/* allow the transfer when at least period_size samples can be processed */</span>
<span class="comment">/* or disable this mechanism when period event is enabled (aka interrupt like style processing) */</span>
err = <a name="a30"></a><a class="code" href="group___p_c_m___s_w___params.html#ga79b12cbbd309750156261e7f5a39167b" title="Set avail min inside a software configuration container.">snd_pcm_sw_params_set_avail_min</a>(handle, swparams, period_event ? buffer_size : period_size);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"Unable to set avail min for playback: %s\n"</span>, <a class="code" href="group___error.html#ga182bbadf2349e11602bc531e8cf22f7e" title="Returns the message for an error code.">snd_strerror</a>(err));
<span class="keywordflow">return</span> err;
}
<span class="comment">/* enable period events when requested */</span>
<span class="keywordflow">if</span> (period_event) {
err = <a name="a31"></a><a class="code" href="group___p_c_m___s_w___params.html#gaf62ce50d6242b4f4dc9d6534a97e5c09" title="Set period event inside a software configuration container.">snd_pcm_sw_params_set_period_event</a>(handle, swparams, 1);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"Unable to set period event: %s\n"</span>, <a class="code" href="group___error.html#ga182bbadf2349e11602bc531e8cf22f7e" title="Returns the message for an error code.">snd_strerror</a>(err));
<span class="keywordflow">return</span> err;
}
}
<span class="comment">/* write the parameters to the playback device */</span>
err = <a name="a32"></a><a class="code" href="group___p_c_m.html#ga891ccaeea2c685a533b61b5fa0493974" title="Install PCM software configuration defined by params.">snd_pcm_sw_params</a>(handle, swparams);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"Unable to set sw params for playback: %s\n"</span>, <a class="code" href="group___error.html#ga182bbadf2349e11602bc531e8cf22f7e" title="Returns the message for an error code.">snd_strerror</a>(err));
<span class="keywordflow">return</span> err;
}
<span class="keywordflow">return</span> 0;
}
<span class="comment">/*</span>
<span class="comment"> * Underrun and suspend recovery</span>
<span class="comment"> */</span>
<span class="keyword">static</span> <span class="keywordtype">int</span> xrun_recovery(<a class="code" href="group___p_c_m.html#ga919e634deecd855b6e2e15174e70d3ea">snd_pcm_t</a> *handle, <span class="keywordtype">int</span> err)
{
<span class="keywordflow">if</span> (verbose)
printf(<span class="stringliteral">"stream recovery\n"</span>);
<span class="keywordflow">if</span> (err == -EPIPE) { <span class="comment">/* under-run */</span>
err = <a name="a33"></a><a class="code" href="group___p_c_m.html#ga788d05de75f2d536f8443cb0306754d0" title="Prepare PCM for use.">snd_pcm_prepare</a>(handle);
<span class="keywordflow">if</span> (err < 0)
printf(<span class="stringliteral">"Can't recovery from underrun, prepare failed: %s\n"</span>, <a class="code" href="group___error.html#ga182bbadf2349e11602bc531e8cf22f7e" title="Returns the message for an error code.">snd_strerror</a>(err));
<span class="keywordflow">return</span> 0;
} <span class="keywordflow">else</span> <span class="keywordflow">if</span> (err == -ESTRPIPE) {
<span class="keywordflow">while</span> ((err = <a name="a34"></a><a class="code" href="group___p_c_m.html#ga13083ce2209aab9ea73831610bc61ab1" title="Resume from suspend, no samples are lost.">snd_pcm_resume</a>(handle)) == -EAGAIN)
sleep(1); <span class="comment">/* wait until the suspend flag is released */</span>
<span class="keywordflow">if</span> (err < 0) {
err = <a class="code" href="group___p_c_m.html#ga788d05de75f2d536f8443cb0306754d0" title="Prepare PCM for use.">snd_pcm_prepare</a>(handle);
<span class="keywordflow">if</span> (err < 0)
printf(<span class="stringliteral">"Can't recovery from suspend, prepare failed: %s\n"</span>, <a class="code" href="group___error.html#ga182bbadf2349e11602bc531e8cf22f7e" title="Returns the message for an error code.">snd_strerror</a>(err));
}
<span class="keywordflow">return</span> 0;
}
<span class="keywordflow">return</span> err;
}
<span class="comment">/*</span>
<span class="comment"> * Transfer method - write only</span>
<span class="comment"> */</span>
<span class="keyword">static</span> <span class="keywordtype">int</span> write_loop(<a class="code" href="group___p_c_m.html#ga919e634deecd855b6e2e15174e70d3ea">snd_pcm_t</a> *handle,
<span class="keywordtype">signed</span> <span class="keywordtype">short</span> *samples,
<a class="code" href="structsnd__pcm__channel__area__t.html">snd_pcm_channel_area_t</a> *areas)
{
<span class="keywordtype">double</span> phase = 0;
<span class="keywordtype">signed</span> <span class="keywordtype">short</span> *ptr;
<span class="keywordtype">int</span> err, cptr;
<span class="keywordflow">while</span> (1) {
generate_sine(areas, 0, period_size, &phase);
ptr = samples;
cptr = period_size;
<span class="keywordflow">while</span> (cptr > 0) {
err = <a name="a35"></a><a class="code" href="group___p_c_m.html#gabc748a500743713eafa960c7d104ca6f" title="Write interleaved frames to a PCM.">snd_pcm_writei</a>(handle, ptr, cptr);
<span class="keywordflow">if</span> (err == -EAGAIN)
<span class="keywordflow">continue</span>;
<span class="keywordflow">if</span> (err < 0) {
<span class="keywordflow">if</span> (xrun_recovery(handle, err) < 0) {
printf(<span class="stringliteral">"Write error: %s\n"</span>, <a class="code" href="group___error.html#ga182bbadf2349e11602bc531e8cf22f7e" title="Returns the message for an error code.">snd_strerror</a>(err));
exit(EXIT_FAILURE);
}
<span class="keywordflow">break</span>; <span class="comment">/* skip one period */</span>
}
ptr += err * channels;
cptr -= err;
}
}
}
<span class="comment">/*</span>
<span class="comment"> * Transfer method - write and wait for room in buffer using poll</span>
<span class="comment"> */</span>
<span class="keyword">static</span> <span class="keywordtype">int</span> wait_for_poll(<a class="code" href="group___p_c_m.html#ga919e634deecd855b6e2e15174e70d3ea">snd_pcm_t</a> *handle, <span class="keyword">struct</span> pollfd *ufds, <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> count)
{
<span class="keywordtype">unsigned</span> <span class="keywordtype">short</span> revents;
<span class="keywordflow">while</span> (1) {
poll(ufds, count, -1);
<a name="a36"></a><a class="code" href="group___p_c_m.html#ga7e561f305702c6f52dab49b6c84f7df7" title="get returned events from poll descriptors">snd_pcm_poll_descriptors_revents</a>(handle, ufds, count, &revents);
<span class="keywordflow">if</span> (revents & POLLERR)
<span class="keywordflow">return</span> -EIO;
<span class="keywordflow">if</span> (revents & POLLOUT)
<span class="keywordflow">return</span> 0;
}
}
<span class="keyword">static</span> <span class="keywordtype">int</span> write_and_poll_loop(<a class="code" href="group___p_c_m.html#ga919e634deecd855b6e2e15174e70d3ea">snd_pcm_t</a> *handle,
<span class="keywordtype">signed</span> <span class="keywordtype">short</span> *samples,
<a class="code" href="structsnd__pcm__channel__area__t.html">snd_pcm_channel_area_t</a> *areas)
{
<span class="keyword">struct </span>pollfd *ufds;
<span class="keywordtype">double</span> phase = 0;
<span class="keywordtype">signed</span> <span class="keywordtype">short</span> *ptr;
<span class="keywordtype">int</span> err, count, cptr, init;
count = <a name="a37"></a><a class="code" href="group___p_c_m.html#gac7f4cdb1c930b8d343714f60afa02fc4" title="get count of poll descriptors for PCM handle">snd_pcm_poll_descriptors_count</a> (handle);
<span class="keywordflow">if</span> (count <= 0) {
printf(<span class="stringliteral">"Invalid poll descriptors count\n"</span>);
<span class="keywordflow">return</span> count;
}
ufds = malloc(<span class="keyword">sizeof</span>(<span class="keyword">struct</span> pollfd) * count);
<span class="keywordflow">if</span> (ufds == NULL) {
printf(<span class="stringliteral">"No enough memory\n"</span>);
<span class="keywordflow">return</span> -ENOMEM;
}
<span class="keywordflow">if</span> ((err = <a name="a38"></a><a class="code" href="group___p_c_m.html#ga742e8705f6992fd0e36efc868e574f01" title="get poll descriptors">snd_pcm_poll_descriptors</a>(handle, ufds, count)) < 0) {
printf(<span class="stringliteral">"Unable to obtain poll descriptors for playback: %s\n"</span>, <a class="code" href="group___error.html#ga182bbadf2349e11602bc531e8cf22f7e" title="Returns the message for an error code.">snd_strerror</a>(err));
<span class="keywordflow">return</span> err;
}
init = 1;
<span class="keywordflow">while</span> (1) {
<span class="keywordflow">if</span> (!init) {
err = wait_for_poll(handle, ufds, count);
<span class="keywordflow">if</span> (err < 0) {
<span class="keywordflow">if</span> (<a name="a39"></a><a class="code" href="group___p_c_m.html#ga87896f6f17020fc19835790369e7ce75" title="Return PCM state.">snd_pcm_state</a>(handle) == <a name="a40"></a><a class="code" href="group___p_c_m.html#gga61ac499cb3701ce536d4d83725908860ab63b5b90201110cd586b686355fd5d83">SND_PCM_STATE_XRUN</a> ||
<a class="code" href="group___p_c_m.html#ga87896f6f17020fc19835790369e7ce75" title="Return PCM state.">snd_pcm_state</a>(handle) == <a name="a41"></a><a class="code" href="group___p_c_m.html#gga61ac499cb3701ce536d4d83725908860a79a05b6b619f88e153d50d9daf2e84bf">SND_PCM_STATE_SUSPENDED</a>) {
err = <a class="code" href="group___p_c_m.html#ga87896f6f17020fc19835790369e7ce75" title="Return PCM state.">snd_pcm_state</a>(handle) == <a class="code" href="group___p_c_m.html#gga61ac499cb3701ce536d4d83725908860ab63b5b90201110cd586b686355fd5d83">SND_PCM_STATE_XRUN</a> ? -EPIPE : -ESTRPIPE;
<span class="keywordflow">if</span> (xrun_recovery(handle, err) < 0) {
printf(<span class="stringliteral">"Write error: %s\n"</span>, <a class="code" href="group___error.html#ga182bbadf2349e11602bc531e8cf22f7e" title="Returns the message for an error code.">snd_strerror</a>(err));
exit(EXIT_FAILURE);
}
init = 1;
} <span class="keywordflow">else</span> {
printf(<span class="stringliteral">"Wait for poll failed\n"</span>);
<span class="keywordflow">return</span> err;
}
}
}
generate_sine(areas, 0, period_size, &phase);
ptr = samples;
cptr = period_size;
<span class="keywordflow">while</span> (cptr > 0) {
err = <a class="code" href="group___p_c_m.html#gabc748a500743713eafa960c7d104ca6f" title="Write interleaved frames to a PCM.">snd_pcm_writei</a>(handle, ptr, cptr);
<span class="keywordflow">if</span> (err < 0) {
<span class="keywordflow">if</span> (xrun_recovery(handle, err) < 0) {
printf(<span class="stringliteral">"Write error: %s\n"</span>, <a class="code" href="group___error.html#ga182bbadf2349e11602bc531e8cf22f7e" title="Returns the message for an error code.">snd_strerror</a>(err));
exit(EXIT_FAILURE);
}
init = 1;
<span class="keywordflow">break</span>; <span class="comment">/* skip one period */</span>
}
<span class="keywordflow">if</span> (<a class="code" href="group___p_c_m.html#ga87896f6f17020fc19835790369e7ce75" title="Return PCM state.">snd_pcm_state</a>(handle) == <a name="a42"></a><a class="code" href="group___p_c_m.html#gga61ac499cb3701ce536d4d83725908860a86f6fbc796881f19fde0e1957f878147">SND_PCM_STATE_RUNNING</a>)
init = 0;
ptr += err * channels;
cptr -= err;
<span class="keywordflow">if</span> (cptr == 0)
<span class="keywordflow">break</span>;
<span class="comment">/* it is possible, that the initial buffer cannot store */</span>
<span class="comment">/* all data from the last period, so wait awhile */</span>
err = wait_for_poll(handle, ufds, count);
<span class="keywordflow">if</span> (err < 0) {
<span class="keywordflow">if</span> (<a class="code" href="group___p_c_m.html#ga87896f6f17020fc19835790369e7ce75" title="Return PCM state.">snd_pcm_state</a>(handle) == <a class="code" href="group___p_c_m.html#gga61ac499cb3701ce536d4d83725908860ab63b5b90201110cd586b686355fd5d83">SND_PCM_STATE_XRUN</a> ||
<a class="code" href="group___p_c_m.html#ga87896f6f17020fc19835790369e7ce75" title="Return PCM state.">snd_pcm_state</a>(handle) == <a class="code" href="group___p_c_m.html#gga61ac499cb3701ce536d4d83725908860a79a05b6b619f88e153d50d9daf2e84bf">SND_PCM_STATE_SUSPENDED</a>) {
err = <a class="code" href="group___p_c_m.html#ga87896f6f17020fc19835790369e7ce75" title="Return PCM state.">snd_pcm_state</a>(handle) == <a class="code" href="group___p_c_m.html#gga61ac499cb3701ce536d4d83725908860ab63b5b90201110cd586b686355fd5d83">SND_PCM_STATE_XRUN</a> ? -EPIPE : -ESTRPIPE;
<span class="keywordflow">if</span> (xrun_recovery(handle, err) < 0) {
printf(<span class="stringliteral">"Write error: %s\n"</span>, <a class="code" href="group___error.html#ga182bbadf2349e11602bc531e8cf22f7e" title="Returns the message for an error code.">snd_strerror</a>(err));
exit(EXIT_FAILURE);
}
init = 1;
} <span class="keywordflow">else</span> {
printf(<span class="stringliteral">"Wait for poll failed\n"</span>);
<span class="keywordflow">return</span> err;
}
}
}
}
}
<span class="comment">/*</span>
<span class="comment"> * Transfer method - asynchronous notification</span>
<span class="comment"> */</span>
<span class="keyword">struct </span>async_private_data {
<span class="keywordtype">signed</span> <span class="keywordtype">short</span> *samples;
<a class="code" href="structsnd__pcm__channel__area__t.html">snd_pcm_channel_area_t</a> *areas;
<span class="keywordtype">double</span> phase;
};
<span class="keyword">static</span> <span class="keywordtype">void</span> async_callback(<a name="a43"></a><a class="code" href="group___global.html#ga8cd9a1d441e9219ca5f2ff04094c7c6d" title="Internal structure for an async notification client handler.">snd_async_handler_t</a> *ahandler)
{
<a class="code" href="group___p_c_m.html#ga919e634deecd855b6e2e15174e70d3ea">snd_pcm_t</a> *handle = <a name="a44"></a><a class="code" href="group___p_c_m.html#gace4920d5943820c395dab8d9cd4fed0a" title="Return PCM handle related to an async handler.">snd_async_handler_get_pcm</a>(ahandler);
<span class="keyword">struct </span>async_private_data *data = <a name="a45"></a><a class="code" href="group___global.html#gad9c76588a87918901c6273e6bc98a1bc" title="Returns the private data assigned to an async handler.">snd_async_handler_get_callback_private</a>(ahandler);
<span class="keywordtype">signed</span> <span class="keywordtype">short</span> *samples = data->samples;
<a class="code" href="structsnd__pcm__channel__area__t.html">snd_pcm_channel_area_t</a> *areas = data->areas;
<a class="code" href="group___p_c_m.html#ga71cdfa37e258d2210b8bd0216bf0c36c">snd_pcm_sframes_t</a> avail;
<span class="keywordtype">int</span> err;
avail = <a name="a46"></a><a class="code" href="group___p_c_m.html#ga8bb836bd0c414b59789d51a5f5379c08" title="Return number of frames ready to be read (capture) / written (playback).">snd_pcm_avail_update</a>(handle);
<span class="keywordflow">while</span> (avail >= period_size) {
generate_sine(areas, 0, period_size, &data->phase);
err = <a class="code" href="group___p_c_m.html#gabc748a500743713eafa960c7d104ca6f" title="Write interleaved frames to a PCM.">snd_pcm_writei</a>(handle, samples, period_size);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"Write error: %s\n"</span>, <a class="code" href="group___error.html#ga182bbadf2349e11602bc531e8cf22f7e" title="Returns the message for an error code.">snd_strerror</a>(err));
exit(EXIT_FAILURE);
}
<span class="keywordflow">if</span> (err != period_size) {
printf(<span class="stringliteral">"Write error: written %i expected %li\n"</span>, err, period_size);
exit(EXIT_FAILURE);
}
avail = <a class="code" href="group___p_c_m.html#ga8bb836bd0c414b59789d51a5f5379c08" title="Return number of frames ready to be read (capture) / written (playback).">snd_pcm_avail_update</a>(handle);
}
}
<span class="keyword">static</span> <span class="keywordtype">int</span> async_loop(<a class="code" href="group___p_c_m.html#ga919e634deecd855b6e2e15174e70d3ea">snd_pcm_t</a> *handle,
<span class="keywordtype">signed</span> <span class="keywordtype">short</span> *samples,
<a class="code" href="structsnd__pcm__channel__area__t.html">snd_pcm_channel_area_t</a> *areas)
{
<span class="keyword">struct </span>async_private_data data;
<a class="code" href="group___global.html#ga8cd9a1d441e9219ca5f2ff04094c7c6d" title="Internal structure for an async notification client handler.">snd_async_handler_t</a> *ahandler;
<span class="keywordtype">int</span> err, count;
data.samples = samples;
data.areas = areas;
data.phase = 0;
err = <a name="a47"></a><a class="code" href="group___p_c_m.html#ga5a0c0da6d0d35a3ac9f6a97567ac3b63" title="Add an async handler for a PCM.">snd_async_add_pcm_handler</a>(&ahandler, handle, async_callback, &data);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"Unable to register async handler\n"</span>);
exit(EXIT_FAILURE);
}
<span class="keywordflow">for</span> (count = 0; count < 2; count++) {
generate_sine(areas, 0, period_size, &data.phase);
err = <a class="code" href="group___p_c_m.html#gabc748a500743713eafa960c7d104ca6f" title="Write interleaved frames to a PCM.">snd_pcm_writei</a>(handle, samples, period_size);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"Initial write error: %s\n"</span>, <a class="code" href="group___error.html#ga182bbadf2349e11602bc531e8cf22f7e" title="Returns the message for an error code.">snd_strerror</a>(err));
exit(EXIT_FAILURE);
}
<span class="keywordflow">if</span> (err != period_size) {
printf(<span class="stringliteral">"Initial write error: written %i expected %li\n"</span>, err, period_size);
exit(EXIT_FAILURE);
}
}
<span class="keywordflow">if</span> (<a class="code" href="group___p_c_m.html#ga87896f6f17020fc19835790369e7ce75" title="Return PCM state.">snd_pcm_state</a>(handle) == <a name="a48"></a><a class="code" href="group___p_c_m.html#gga61ac499cb3701ce536d4d83725908860a3eb4a3b75c7d2adb22f1829f3f738b27">SND_PCM_STATE_PREPARED</a>) {
err = <a name="a49"></a><a class="code" href="group___p_c_m.html#ga6bdb88b68a9d9e66015d770f600c6aea" title="Start a PCM.">snd_pcm_start</a>(handle);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"Start error: %s\n"</span>, <a class="code" href="group___error.html#ga182bbadf2349e11602bc531e8cf22f7e" title="Returns the message for an error code.">snd_strerror</a>(err));
exit(EXIT_FAILURE);
}
}
<span class="comment">/* because all other work is done in the signal handler,</span>
<span class="comment"> suspend the process */</span>
<span class="keywordflow">while</span> (1) {
sleep(1);
}
}
<span class="comment">/*</span>
<span class="comment"> * Transfer method - asynchronous notification + direct write</span>
<span class="comment"> */</span>
<span class="keyword">static</span> <span class="keywordtype">void</span> async_direct_callback(<a class="code" href="group___global.html#ga8cd9a1d441e9219ca5f2ff04094c7c6d" title="Internal structure for an async notification client handler.">snd_async_handler_t</a> *ahandler)
{
<a class="code" href="group___p_c_m.html#ga919e634deecd855b6e2e15174e70d3ea">snd_pcm_t</a> *handle = <a class="code" href="group___p_c_m.html#gace4920d5943820c395dab8d9cd4fed0a" title="Return PCM handle related to an async handler.">snd_async_handler_get_pcm</a>(ahandler);
<span class="keyword">struct </span>async_private_data *data = <a class="code" href="group___global.html#gad9c76588a87918901c6273e6bc98a1bc" title="Returns the private data assigned to an async handler.">snd_async_handler_get_callback_private</a>(ahandler);
<span class="keyword">const</span> <a class="code" href="structsnd__pcm__channel__area__t.html">snd_pcm_channel_area_t</a> *my_areas;
<a class="code" href="group___p_c_m.html#gab01fcfe9b97382a8d3f2027c664b8b8a">snd_pcm_uframes_t</a> offset, frames, size;
<a class="code" href="group___p_c_m.html#ga71cdfa37e258d2210b8bd0216bf0c36c">snd_pcm_sframes_t</a> avail, commitres;
<a class="code" href="group___p_c_m.html#ga61ac499cb3701ce536d4d83725908860">snd_pcm_state_t</a> state;
<span class="keywordtype">int</span> first = 0, err;
<span class="keywordflow">while</span> (1) {
state = <a class="code" href="group___p_c_m.html#ga87896f6f17020fc19835790369e7ce75" title="Return PCM state.">snd_pcm_state</a>(handle);
<span class="keywordflow">if</span> (state == <a class="code" href="group___p_c_m.html#gga61ac499cb3701ce536d4d83725908860ab63b5b90201110cd586b686355fd5d83">SND_PCM_STATE_XRUN</a>) {
err = xrun_recovery(handle, -EPIPE);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"XRUN recovery failed: %s\n"</span>, <a class="code" href="group___error.html#ga182bbadf2349e11602bc531e8cf22f7e" title="Returns the message for an error code.">snd_strerror</a>(err));
exit(EXIT_FAILURE);
}
first = 1;
} <span class="keywordflow">else</span> <span class="keywordflow">if</span> (state == <a class="code" href="group___p_c_m.html#gga61ac499cb3701ce536d4d83725908860a79a05b6b619f88e153d50d9daf2e84bf">SND_PCM_STATE_SUSPENDED</a>) {
err = xrun_recovery(handle, -ESTRPIPE);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"SUSPEND recovery failed: %s\n"</span>, <a class="code" href="group___error.html#ga182bbadf2349e11602bc531e8cf22f7e" title="Returns the message for an error code.">snd_strerror</a>(err));
exit(EXIT_FAILURE);
}
}
avail = <a class="code" href="group___p_c_m.html#ga8bb836bd0c414b59789d51a5f5379c08" title="Return number of frames ready to be read (capture) / written (playback).">snd_pcm_avail_update</a>(handle);
<span class="keywordflow">if</span> (avail < 0) {
err = xrun_recovery(handle, avail);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"avail update failed: %s\n"</span>, <a class="code" href="group___error.html#ga182bbadf2349e11602bc531e8cf22f7e" title="Returns the message for an error code.">snd_strerror</a>(err));
exit(EXIT_FAILURE);
}
first = 1;
<span class="keywordflow">continue</span>;
}
<span class="keywordflow">if</span> (avail < period_size) {
<span class="keywordflow">if</span> (first) {
first = 0;
err = <a class="code" href="group___p_c_m.html#ga6bdb88b68a9d9e66015d770f600c6aea" title="Start a PCM.">snd_pcm_start</a>(handle);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"Start error: %s\n"</span>, <a class="code" href="group___error.html#ga182bbadf2349e11602bc531e8cf22f7e" title="Returns the message for an error code.">snd_strerror</a>(err));
exit(EXIT_FAILURE);
}
} <span class="keywordflow">else</span> {
<span class="keywordflow">break</span>;
}
<span class="keywordflow">continue</span>;
}
size = period_size;
<span class="keywordflow">while</span> (size > 0) {
frames = size;
err = <a name="a50"></a><a class="code" href="group___p_c_m___direct.html#ga6d4acf42de554d4d1177fb035d484ea4" title="Application request to access a portion of direct (mmap) area.">snd_pcm_mmap_begin</a>(handle, &my_areas, &offset, &frames);
<span class="keywordflow">if</span> (err < 0) {
<span class="keywordflow">if</span> ((err = xrun_recovery(handle, err)) < 0) {
printf(<span class="stringliteral">"MMAP begin avail error: %s\n"</span>, <a class="code" href="group___error.html#ga182bbadf2349e11602bc531e8cf22f7e" title="Returns the message for an error code.">snd_strerror</a>(err));
exit(EXIT_FAILURE);
}
first = 1;
}
generate_sine(my_areas, offset, frames, &data->phase);
commitres = <a name="a51"></a><a class="code" href="group___p_c_m___direct.html#gac306bd13c305825aa39dd9180a3ad520" title="Application has completed the access to area requested with snd_pcm_mmap_begin.">snd_pcm_mmap_commit</a>(handle, offset, frames);
<span class="keywordflow">if</span> (commitres < 0 || (<a class="code" href="group___p_c_m.html#gab01fcfe9b97382a8d3f2027c664b8b8a">snd_pcm_uframes_t</a>)commitres != frames) {
<span class="keywordflow">if</span> ((err = xrun_recovery(handle, commitres >= 0 ? -EPIPE : commitres)) < 0) {
printf(<span class="stringliteral">"MMAP commit error: %s\n"</span>, <a class="code" href="group___error.html#ga182bbadf2349e11602bc531e8cf22f7e" title="Returns the message for an error code.">snd_strerror</a>(err));
exit(EXIT_FAILURE);
}
first = 1;
}
size -= frames;
}
}
}
<span class="keyword">static</span> <span class="keywordtype">int</span> async_direct_loop(<a class="code" href="group___p_c_m.html#ga919e634deecd855b6e2e15174e70d3ea">snd_pcm_t</a> *handle,
<span class="keywordtype">signed</span> <span class="keywordtype">short</span> *samples ATTRIBUTE_UNUSED,
<a class="code" href="structsnd__pcm__channel__area__t.html">snd_pcm_channel_area_t</a> *areas ATTRIBUTE_UNUSED)
{
<span class="keyword">struct </span>async_private_data data;
<a class="code" href="group___global.html#ga8cd9a1d441e9219ca5f2ff04094c7c6d" title="Internal structure for an async notification client handler.">snd_async_handler_t</a> *ahandler;
<span class="keyword">const</span> <a class="code" href="structsnd__pcm__channel__area__t.html">snd_pcm_channel_area_t</a> *my_areas;
<a class="code" href="group___p_c_m.html#gab01fcfe9b97382a8d3f2027c664b8b8a">snd_pcm_uframes_t</a> offset, frames, size;
<a class="code" href="group___p_c_m.html#ga71cdfa37e258d2210b8bd0216bf0c36c">snd_pcm_sframes_t</a> commitres;
<span class="keywordtype">int</span> err, count;
data.samples = NULL; <span class="comment">/* we do not require the global sample area for direct write */</span>
data.areas = NULL; <span class="comment">/* we do not require the global areas for direct write */</span>
data.phase = 0;
err = <a class="code" href="group___p_c_m.html#ga5a0c0da6d0d35a3ac9f6a97567ac3b63" title="Add an async handler for a PCM.">snd_async_add_pcm_handler</a>(&ahandler, handle, async_direct_callback, &data);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"Unable to register async handler\n"</span>);
exit(EXIT_FAILURE);
}
<span class="keywordflow">for</span> (count = 0; count < 2; count++) {
size = period_size;
<span class="keywordflow">while</span> (size > 0) {
frames = size;
err = <a class="code" href="group___p_c_m___direct.html#ga6d4acf42de554d4d1177fb035d484ea4" title="Application request to access a portion of direct (mmap) area.">snd_pcm_mmap_begin</a>(handle, &my_areas, &offset, &frames);
<span class="keywordflow">if</span> (err < 0) {
<span class="keywordflow">if</span> ((err = xrun_recovery(handle, err)) < 0) {
printf(<span class="stringliteral">"MMAP begin avail error: %s\n"</span>, <a class="code" href="group___error.html#ga182bbadf2349e11602bc531e8cf22f7e" title="Returns the message for an error code.">snd_strerror</a>(err));
exit(EXIT_FAILURE);
}
}
generate_sine(my_areas, offset, frames, &data.phase);
commitres = <a class="code" href="group___p_c_m___direct.html#gac306bd13c305825aa39dd9180a3ad520" title="Application has completed the access to area requested with snd_pcm_mmap_begin.">snd_pcm_mmap_commit</a>(handle, offset, frames);
<span class="keywordflow">if</span> (commitres < 0 || (<a class="code" href="group___p_c_m.html#gab01fcfe9b97382a8d3f2027c664b8b8a">snd_pcm_uframes_t</a>)commitres != frames) {
<span class="keywordflow">if</span> ((err = xrun_recovery(handle, commitres >= 0 ? -EPIPE : commitres)) < 0) {
printf(<span class="stringliteral">"MMAP commit error: %s\n"</span>, <a class="code" href="group___error.html#ga182bbadf2349e11602bc531e8cf22f7e" title="Returns the message for an error code.">snd_strerror</a>(err));
exit(EXIT_FAILURE);
}
}
size -= frames;
}
}
err = <a class="code" href="group___p_c_m.html#ga6bdb88b68a9d9e66015d770f600c6aea" title="Start a PCM.">snd_pcm_start</a>(handle);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"Start error: %s\n"</span>, <a class="code" href="group___error.html#ga182bbadf2349e11602bc531e8cf22f7e" title="Returns the message for an error code.">snd_strerror</a>(err));
exit(EXIT_FAILURE);
}
<span class="comment">/* because all other work is done in the signal handler,</span>
<span class="comment"> suspend the process */</span>
<span class="keywordflow">while</span> (1) {
sleep(1);
}
}
<span class="comment">/*</span>
<span class="comment"> * Transfer method - direct write only</span>
<span class="comment"> */</span>
<span class="keyword">static</span> <span class="keywordtype">int</span> direct_loop(<a class="code" href="group___p_c_m.html#ga919e634deecd855b6e2e15174e70d3ea">snd_pcm_t</a> *handle,
<span class="keywordtype">signed</span> <span class="keywordtype">short</span> *samples ATTRIBUTE_UNUSED,
<a class="code" href="structsnd__pcm__channel__area__t.html">snd_pcm_channel_area_t</a> *areas ATTRIBUTE_UNUSED)
{
<span class="keywordtype">double</span> phase = 0;
<span class="keyword">const</span> <a class="code" href="structsnd__pcm__channel__area__t.html">snd_pcm_channel_area_t</a> *my_areas;
<a class="code" href="group___p_c_m.html#gab01fcfe9b97382a8d3f2027c664b8b8a">snd_pcm_uframes_t</a> offset, frames, size;
<a class="code" href="group___p_c_m.html#ga71cdfa37e258d2210b8bd0216bf0c36c">snd_pcm_sframes_t</a> avail, commitres;
<a class="code" href="group___p_c_m.html#ga61ac499cb3701ce536d4d83725908860">snd_pcm_state_t</a> state;
<span class="keywordtype">int</span> err, first = 1;
<span class="keywordflow">while</span> (1) {
state = <a class="code" href="group___p_c_m.html#ga87896f6f17020fc19835790369e7ce75" title="Return PCM state.">snd_pcm_state</a>(handle);
<span class="keywordflow">if</span> (state == <a class="code" href="group___p_c_m.html#gga61ac499cb3701ce536d4d83725908860ab63b5b90201110cd586b686355fd5d83">SND_PCM_STATE_XRUN</a>) {
err = xrun_recovery(handle, -EPIPE);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"XRUN recovery failed: %s\n"</span>, <a class="code" href="group___error.html#ga182bbadf2349e11602bc531e8cf22f7e" title="Returns the message for an error code.">snd_strerror</a>(err));
<span class="keywordflow">return</span> err;
}
first = 1;
} <span class="keywordflow">else</span> <span class="keywordflow">if</span> (state == <a class="code" href="group___p_c_m.html#gga61ac499cb3701ce536d4d83725908860a79a05b6b619f88e153d50d9daf2e84bf">SND_PCM_STATE_SUSPENDED</a>) {
err = xrun_recovery(handle, -ESTRPIPE);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"SUSPEND recovery failed: %s\n"</span>, <a class="code" href="group___error.html#ga182bbadf2349e11602bc531e8cf22f7e" title="Returns the message for an error code.">snd_strerror</a>(err));
<span class="keywordflow">return</span> err;
}
}
avail = <a class="code" href="group___p_c_m.html#ga8bb836bd0c414b59789d51a5f5379c08" title="Return number of frames ready to be read (capture) / written (playback).">snd_pcm_avail_update</a>(handle);
<span class="keywordflow">if</span> (avail < 0) {
err = xrun_recovery(handle, avail);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"avail update failed: %s\n"</span>, <a class="code" href="group___error.html#ga182bbadf2349e11602bc531e8cf22f7e" title="Returns the message for an error code.">snd_strerror</a>(err));
<span class="keywordflow">return</span> err;
}
first = 1;
<span class="keywordflow">continue</span>;
}
<span class="keywordflow">if</span> (avail < period_size) {
<span class="keywordflow">if</span> (first) {
first = 0;
err = <a class="code" href="group___p_c_m.html#ga6bdb88b68a9d9e66015d770f600c6aea" title="Start a PCM.">snd_pcm_start</a>(handle);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"Start error: %s\n"</span>, <a class="code" href="group___error.html#ga182bbadf2349e11602bc531e8cf22f7e" title="Returns the message for an error code.">snd_strerror</a>(err));
exit(EXIT_FAILURE);
}
} <span class="keywordflow">else</span> {
err = <a name="a52"></a><a class="code" href="group___p_c_m.html#gad4d53d58b996a7cd9a5cbf1710b90375" title="Wait for a PCM to become ready.">snd_pcm_wait</a>(handle, -1);
<span class="keywordflow">if</span> (err < 0) {
<span class="keywordflow">if</span> ((err = xrun_recovery(handle, err)) < 0) {
printf(<span class="stringliteral">"snd_pcm_wait error: %s\n"</span>, <a class="code" href="group___error.html#ga182bbadf2349e11602bc531e8cf22f7e" title="Returns the message for an error code.">snd_strerror</a>(err));
exit(EXIT_FAILURE);
}
first = 1;
}
}
<span class="keywordflow">continue</span>;
}
size = period_size;
<span class="keywordflow">while</span> (size > 0) {
frames = size;
err = <a class="code" href="group___p_c_m___direct.html#ga6d4acf42de554d4d1177fb035d484ea4" title="Application request to access a portion of direct (mmap) area.">snd_pcm_mmap_begin</a>(handle, &my_areas, &offset, &frames);
<span class="keywordflow">if</span> (err < 0) {
<span class="keywordflow">if</span> ((err = xrun_recovery(handle, err)) < 0) {
printf(<span class="stringliteral">"MMAP begin avail error: %s\n"</span>, <a class="code" href="group___error.html#ga182bbadf2349e11602bc531e8cf22f7e" title="Returns the message for an error code.">snd_strerror</a>(err));
exit(EXIT_FAILURE);
}
first = 1;
}
generate_sine(my_areas, offset, frames, &phase);
commitres = <a class="code" href="group___p_c_m___direct.html#gac306bd13c305825aa39dd9180a3ad520" title="Application has completed the access to area requested with snd_pcm_mmap_begin.">snd_pcm_mmap_commit</a>(handle, offset, frames);
<span class="keywordflow">if</span> (commitres < 0 || (<a class="code" href="group___p_c_m.html#gab01fcfe9b97382a8d3f2027c664b8b8a">snd_pcm_uframes_t</a>)commitres != frames) {
<span class="keywordflow">if</span> ((err = xrun_recovery(handle, commitres >= 0 ? -EPIPE : commitres)) < 0) {
printf(<span class="stringliteral">"MMAP commit error: %s\n"</span>, <a class="code" href="group___error.html#ga182bbadf2349e11602bc531e8cf22f7e" title="Returns the message for an error code.">snd_strerror</a>(err));
exit(EXIT_FAILURE);
}
first = 1;
}
size -= frames;
}
}
}
<span class="comment">/*</span>
<span class="comment"> * Transfer method - direct write only using mmap_write functions</span>
<span class="comment"> */</span>
<span class="keyword">static</span> <span class="keywordtype">int</span> direct_write_loop(<a class="code" href="group___p_c_m.html#ga919e634deecd855b6e2e15174e70d3ea">snd_pcm_t</a> *handle,
<span class="keywordtype">signed</span> <span class="keywordtype">short</span> *samples,
<a class="code" href="structsnd__pcm__channel__area__t.html">snd_pcm_channel_area_t</a> *areas)
{
<span class="keywordtype">double</span> phase = 0;
<span class="keywordtype">signed</span> <span class="keywordtype">short</span> *ptr;
<span class="keywordtype">int</span> err, cptr;
<span class="keywordflow">while</span> (1) {
generate_sine(areas, 0, period_size, &phase);
ptr = samples;
cptr = period_size;
<span class="keywordflow">while</span> (cptr > 0) {
err = <a name="a53"></a><a class="code" href="group___p_c_m___direct.html#ga5a9ee8e1e764b12da6d54dfa195f7c52" title="Write interleaved frames to a PCM using direct buffer (mmap).">snd_pcm_mmap_writei</a>(handle, ptr, cptr);
<span class="keywordflow">if</span> (err == -EAGAIN)
<span class="keywordflow">continue</span>;
<span class="keywordflow">if</span> (err < 0) {
<span class="keywordflow">if</span> (xrun_recovery(handle, err) < 0) {
printf(<span class="stringliteral">"Write error: %s\n"</span>, <a class="code" href="group___error.html#ga182bbadf2349e11602bc531e8cf22f7e" title="Returns the message for an error code.">snd_strerror</a>(err));
exit(EXIT_FAILURE);
}
<span class="keywordflow">break</span>; <span class="comment">/* skip one period */</span>
}
ptr += err * channels;
cptr -= err;
}
}
}
<span class="comment">/*</span>
<span class="comment"> *</span>
<span class="comment"> */</span>
<span class="keyword">struct </span>transfer_method {
<span class="keyword">const</span> <span class="keywordtype">char</span> *name;
<a class="code" href="group___p_c_m.html#ga661221ba5e8f1d6eaf4ab8e2da57cc1a">snd_pcm_access_t</a> access;
int (*transfer_loop)(<a class="code" href="group___p_c_m.html#ga919e634deecd855b6e2e15174e70d3ea">snd_pcm_t</a> *handle,
<span class="keywordtype">signed</span> <span class="keywordtype">short</span> *samples,
<a class="code" href="structsnd__pcm__channel__area__t.html">snd_pcm_channel_area_t</a> *areas);
};
<span class="keyword">static</span> <span class="keyword">struct </span>transfer_method transfer_methods[] = {
{ <span class="stringliteral">"write"</span>, <a name="a54"></a><a class="code" href="group___p_c_m.html#gga661221ba5e8f1d6eaf4ab8e2da57cc1aa72a970ed6e676ab0fd9f3c3d36737e0a">SND_PCM_ACCESS_RW_INTERLEAVED</a>, write_loop },
{ <span class="stringliteral">"write_and_poll"</span>, <a class="code" href="group___p_c_m.html#gga661221ba5e8f1d6eaf4ab8e2da57cc1aa72a970ed6e676ab0fd9f3c3d36737e0a">SND_PCM_ACCESS_RW_INTERLEAVED</a>, write_and_poll_loop },
{ <span class="stringliteral">"async"</span>, <a class="code" href="group___p_c_m.html#gga661221ba5e8f1d6eaf4ab8e2da57cc1aa72a970ed6e676ab0fd9f3c3d36737e0a">SND_PCM_ACCESS_RW_INTERLEAVED</a>, async_loop },
{ <span class="stringliteral">"async_direct"</span>, <a name="a55"></a><a class="code" href="group___p_c_m.html#gga661221ba5e8f1d6eaf4ab8e2da57cc1aa90a5dea527c5ae9a53f1448beb2dee6f">SND_PCM_ACCESS_MMAP_INTERLEAVED</a>, async_direct_loop },
{ <span class="stringliteral">"direct_interleaved"</span>, <a class="code" href="group___p_c_m.html#gga661221ba5e8f1d6eaf4ab8e2da57cc1aa90a5dea527c5ae9a53f1448beb2dee6f">SND_PCM_ACCESS_MMAP_INTERLEAVED</a>, direct_loop },
{ <span class="stringliteral">"direct_noninterleaved"</span>, <a name="a56"></a><a class="code" href="group___p_c_m.html#gga661221ba5e8f1d6eaf4ab8e2da57cc1aa7de225785e05dd1d538203c5ece9036e">SND_PCM_ACCESS_MMAP_NONINTERLEAVED</a>, direct_loop },
{ <span class="stringliteral">"direct_write"</span>, <a class="code" href="group___p_c_m.html#gga661221ba5e8f1d6eaf4ab8e2da57cc1aa90a5dea527c5ae9a53f1448beb2dee6f">SND_PCM_ACCESS_MMAP_INTERLEAVED</a>, direct_write_loop },
{ NULL, <a class="code" href="group___p_c_m.html#gga661221ba5e8f1d6eaf4ab8e2da57cc1aa72a970ed6e676ab0fd9f3c3d36737e0a">SND_PCM_ACCESS_RW_INTERLEAVED</a>, NULL }
};
<span class="keyword">static</span> <span class="keywordtype">void</span> help(<span class="keywordtype">void</span>)
{
<span class="keywordtype">int</span> k;
printf(
<span class="stringliteral">"Usage: pcm [OPTION]... [FILE]...\n"</span>
<span class="stringliteral">"-h,--help help\n"</span>
<span class="stringliteral">"-D,--device playback device\n"</span>
<span class="stringliteral">"-r,--rate stream rate in Hz\n"</span>
<span class="stringliteral">"-c,--channels count of channels in stream\n"</span>
<span class="stringliteral">"-f,--frequency sine wave frequency in Hz\n"</span>
<span class="stringliteral">"-b,--buffer ring buffer size in us\n"</span>
<span class="stringliteral">"-p,--period period size in us\n"</span>
<span class="stringliteral">"-m,--method transfer method\n"</span>
<span class="stringliteral">"-o,--format sample format\n"</span>
<span class="stringliteral">"-v,--verbose show the PCM setup parameters\n"</span>
<span class="stringliteral">"-n,--noresample do not resample\n"</span>
<span class="stringliteral">"-e,--pevent enable poll event after each period\n"</span>
<span class="stringliteral">"\n"</span>);
printf(<span class="stringliteral">"Recognized sample formats are:"</span>);
<span class="keywordflow">for</span> (k = 0; k < SND_PCM_FORMAT_LAST; ++k) {
<span class="keyword">const</span> <span class="keywordtype">char</span> *s = <a name="a57"></a><a class="code" href="group___p_c_m___description.html#ga2ca258b8ac569ca35f283e48d2181e45" title="get name of PCM sample format">snd_pcm_format_name</a>(k);
<span class="keywordflow">if</span> (s)
printf(<span class="stringliteral">" %s"</span>, s);
}
printf(<span class="stringliteral">"\n"</span>);
printf(<span class="stringliteral">"Recognized transfer methods are:"</span>);
<span class="keywordflow">for</span> (k = 0; transfer_methods[k].name; k++)
printf(<span class="stringliteral">" %s"</span>, transfer_methods[k].name);
printf(<span class="stringliteral">"\n"</span>);
}
<span class="keywordtype">int</span> main(<span class="keywordtype">int</span> argc, <span class="keywordtype">char</span> *argv[])
{
<span class="keyword">struct </span>option long_option[] =
{
{<span class="stringliteral">"help"</span>, 0, NULL, <span class="charliteral">'h'</span>},
{<span class="stringliteral">"device"</span>, 1, NULL, <span class="charliteral">'D'</span>},
{<span class="stringliteral">"rate"</span>, 1, NULL, <span class="charliteral">'r'</span>},
{<span class="stringliteral">"channels"</span>, 1, NULL, <span class="charliteral">'c'</span>},
{<span class="stringliteral">"frequency"</span>, 1, NULL, <span class="charliteral">'f'</span>},
{<span class="stringliteral">"buffer"</span>, 1, NULL, <span class="charliteral">'b'</span>},
{<span class="stringliteral">"period"</span>, 1, NULL, <span class="charliteral">'p'</span>},
{<span class="stringliteral">"method"</span>, 1, NULL, <span class="charliteral">'m'</span>},
{<span class="stringliteral">"format"</span>, 1, NULL, <span class="charliteral">'o'</span>},
{<span class="stringliteral">"verbose"</span>, 1, NULL, <span class="charliteral">'v'</span>},
{<span class="stringliteral">"noresample"</span>, 1, NULL, <span class="charliteral">'n'</span>},
{<span class="stringliteral">"pevent"</span>, 1, NULL, <span class="charliteral">'e'</span>},
{NULL, 0, NULL, 0},
};
<a class="code" href="group___p_c_m.html#ga919e634deecd855b6e2e15174e70d3ea">snd_pcm_t</a> *handle;
<span class="keywordtype">int</span> err, morehelp;
<a class="code" href="group___p_c_m.html#ga65c737127994f0a980edad744e36dc40">snd_pcm_hw_params_t</a> *hwparams;
<a class="code" href="group___p_c_m.html#ga7e082d9ea701709270b0674a0be23b09">snd_pcm_sw_params_t</a> *swparams;
<span class="keywordtype">int</span> method = 0;
<span class="keywordtype">signed</span> <span class="keywordtype">short</span> *samples;
<span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> chn;
<a class="code" href="structsnd__pcm__channel__area__t.html">snd_pcm_channel_area_t</a> *areas;
<a name="a58"></a><a class="code" href="group___p_c_m___h_w___params.html#ga06b83cb9a788f99b7b09b570b4355cee" title="allocate an invalid snd_pcm_hw_params_t using standard alloca">snd_pcm_hw_params_alloca</a>(&hwparams);
<a name="a59"></a><a class="code" href="group___p_c_m___s_w___params.html#ga8e564553bdc89948c918729e3cc7beb0" title="allocate an invalid snd_pcm_sw_params_t using standard alloca">snd_pcm_sw_params_alloca</a>(&swparams);
morehelp = 0;
<span class="keywordflow">while</span> (1) {
<span class="keywordtype">int</span> c;
<span class="keywordflow">if</span> ((c = getopt_long(argc, argv, <span class="stringliteral">"hD:r:c:f:b:p:m:o:vne"</span>, long_option, NULL)) < 0)
<span class="keywordflow">break</span>;
<span class="keywordflow">switch</span> (c) {
<span class="keywordflow">case</span> <span class="charliteral">'h'</span>:
morehelp++;
<span class="keywordflow">break</span>;
<span class="keywordflow">case</span> <span class="charliteral">'D'</span>:
device = strdup(optarg);
<span class="keywordflow">break</span>;
<span class="keywordflow">case</span> <span class="charliteral">'r'</span>:
rate = atoi(optarg);
rate = rate < 4000 ? 4000 : rate;
rate = rate > 196000 ? 196000 : rate;
<span class="keywordflow">break</span>;
<span class="keywordflow">case</span> <span class="charliteral">'c'</span>:
channels = atoi(optarg);
channels = channels < 1 ? 1 : channels;
channels = channels > 1024 ? 1024 : channels;
<span class="keywordflow">break</span>;
<span class="keywordflow">case</span> <span class="charliteral">'f'</span>:
freq = atoi(optarg);
freq = freq < 50 ? 50 : freq;
freq = freq > 5000 ? 5000 : freq;
<span class="keywordflow">break</span>;
<span class="keywordflow">case</span> <span class="charliteral">'b'</span>:
buffer_time = atoi(optarg);
buffer_time = buffer_time < 1000 ? 1000 : buffer_time;
buffer_time = buffer_time > 1000000 ? 1000000 : buffer_time;
<span class="keywordflow">break</span>;
<span class="keywordflow">case</span> <span class="charliteral">'p'</span>:
period_time = atoi(optarg);
period_time = period_time < 1000 ? 1000 : period_time;
period_time = period_time > 1000000 ? 1000000 : period_time;
<span class="keywordflow">break</span>;
<span class="keywordflow">case</span> <span class="charliteral">'m'</span>:
<span class="keywordflow">for</span> (method = 0; transfer_methods[method].name; method++)
<span class="keywordflow">if</span> (!strcasecmp(transfer_methods[method].name, optarg))
<span class="keywordflow">break</span>;
<span class="keywordflow">if</span> (transfer_methods[method].name == NULL)
method = 0;
<span class="keywordflow">break</span>;
<span class="keywordflow">case</span> <span class="charliteral">'o'</span>:
<span class="keywordflow">for</span> (format = 0; format < SND_PCM_FORMAT_LAST; format++) {
<span class="keyword">const</span> <span class="keywordtype">char</span> *format_name = <a class="code" href="group___p_c_m___description.html#ga2ca258b8ac569ca35f283e48d2181e45" title="get name of PCM sample format">snd_pcm_format_name</a>(format);
<span class="keywordflow">if</span> (format_name)
<span class="keywordflow">if</span> (!strcasecmp(format_name, optarg))
<span class="keywordflow">break</span>;
}
<span class="keywordflow">if</span> (format == SND_PCM_FORMAT_LAST)
format = <a class="code" href="group___p_c_m.html#ggaa14b7f26877a812acbb39811364177f8aac4470b6be81c22af0cfe528bee4a474">SND_PCM_FORMAT_S16</a>;
<span class="keywordflow">if</span> (!<a name="a60"></a><a class="code" href="group___p_c_m___helpers.html#ga5a52bb63323f463198dea3f3c6aca571" title="Return linear info for a PCM sample format.">snd_pcm_format_linear</a>(format) &&
!(format == <a class="code" href="group___p_c_m.html#ggaa14b7f26877a812acbb39811364177f8a083f32474a84d344e0da496470085c8f">SND_PCM_FORMAT_FLOAT_LE</a> ||
format == <a class="code" href="group___p_c_m.html#ggaa14b7f26877a812acbb39811364177f8ab24eac408b0d2ae6b5f68ed3a7cd2d75">SND_PCM_FORMAT_FLOAT_BE</a>)) {
printf(<span class="stringliteral">"Invalid (non-linear/float) format %s\n"</span>,
optarg);
<span class="keywordflow">return</span> 1;
}
<span class="keywordflow">break</span>;
<span class="keywordflow">case</span> <span class="charliteral">'v'</span>:
verbose = 1;
<span class="keywordflow">break</span>;
<span class="keywordflow">case</span> <span class="charliteral">'n'</span>:
resample = 0;
<span class="keywordflow">break</span>;
<span class="keywordflow">case</span> <span class="charliteral">'e'</span>:
period_event = 1;
<span class="keywordflow">break</span>;
}
}
<span class="keywordflow">if</span> (morehelp) {
help();
<span class="keywordflow">return</span> 0;
}
err = <a name="a61"></a><a class="code" href="group___output.html#gaca78d01bf6d081274650794861373c7d" title="Creates a new output object using an existing stdio FILE pointer.">snd_output_stdio_attach</a>(&output, stdout, 0);
<span class="keywordflow">if</span> (err < 0) {
printf(<span class="stringliteral">"Output failed: %s\n"</span>, <a class="code" href="group___error.html#ga182bbadf2349e11602bc531e8cf22f7e" title="Returns the message for an error code.">snd_strerror</a>(err));
<span class="keywordflow">return</span> 0;
}
printf(<span class="stringliteral">"Playback device is %s\n"</span>, device);
printf(<span class="stringliteral">"Stream parameters are %iHz, %s, %i channels\n"</span>, rate, <a class="code" href="group___p_c_m___description.html#ga2ca258b8ac569ca35f283e48d2181e45" title="get name of PCM sample format">snd_pcm_format_name</a>(format), channels);
printf(<span class="stringliteral">"Sine wave rate is %.4fHz\n"</span>, freq);
printf(<span class="stringliteral">"Using transfer method: %s\n"</span>, transfer_methods[method].name);
<span class="keywordflow">if</span> ((err = <a name="a62"></a><a class="code" href="group___p_c_m.html#ga8340c7dc0ac37f37afe5e7c21d6c528b" title="Opens a PCM.">snd_pcm_open</a>(&handle, device, <a name="a63"></a><a class="code" href="group___p_c_m.html#ggac23b43ff55add78638e503b9cc892c24a57a2b920dbc34173479fc9036cfc78a1">SND_PCM_STREAM_PLAYBACK</a>, 0)) < 0) {
printf(<span class="stringliteral">"Playback open error: %s\n"</span>, <a class="code" href="group___error.html#ga182bbadf2349e11602bc531e8cf22f7e" title="Returns the message for an error code.">snd_strerror</a>(err));
<span class="keywordflow">return</span> 0;
}
<span class="keywordflow">if</span> ((err = set_hwparams(handle, hwparams, transfer_methods[method].access)) < 0) {
printf(<span class="stringliteral">"Setting of hwparams failed: %s\n"</span>, <a class="code" href="group___error.html#ga182bbadf2349e11602bc531e8cf22f7e" title="Returns the message for an error code.">snd_strerror</a>(err));
exit(EXIT_FAILURE);
}
<span class="keywordflow">if</span> ((err = set_swparams(handle, swparams)) < 0) {
printf(<span class="stringliteral">"Setting of swparams failed: %s\n"</span>, <a class="code" href="group___error.html#ga182bbadf2349e11602bc531e8cf22f7e" title="Returns the message for an error code.">snd_strerror</a>(err));
exit(EXIT_FAILURE);
}
<span class="keywordflow">if</span> (verbose > 0)
<a name="a64"></a><a class="code" href="group___p_c_m___dump.html#ga9c5c879409c504e155e234905d031d8d" title="Dump PCM info.">snd_pcm_dump</a>(handle, output);
samples = malloc((period_size * channels * <a class="code" href="group___p_c_m___helpers.html#gaa3e0ff7560342e5af2b5c7bd2d63a307" title="Return bits needed to store a PCM sample.">snd_pcm_format_physical_width</a>(format)) / 8);
<span class="keywordflow">if</span> (samples == NULL) {
printf(<span class="stringliteral">"No enough memory\n"</span>);
exit(EXIT_FAILURE);
}
areas = calloc(channels, <span class="keyword">sizeof</span>(<a class="code" href="structsnd__pcm__channel__area__t.html">snd_pcm_channel_area_t</a>));
<span class="keywordflow">if</span> (areas == NULL) {
printf(<span class="stringliteral">"No enough memory\n"</span>);
exit(EXIT_FAILURE);
}
<span class="keywordflow">for</span> (chn = 0; chn < channels; chn++) {
areas[chn].<a name="a65"></a><a class="code" href="structsnd__pcm__channel__area__t.html#a83acdf3245dcb74dffe74cce53d65876">addr</a> = samples;
areas[chn].<a class="code" href="structsnd__pcm__channel__area__t.html#aba2a69e0d221beaa9f2f115254cb515a">first</a> = chn * <a class="code" href="group___p_c_m___helpers.html#gaa3e0ff7560342e5af2b5c7bd2d63a307" title="Return bits needed to store a PCM sample.">snd_pcm_format_physical_width</a>(format);
areas[chn].<a class="code" href="structsnd__pcm__channel__area__t.html#aedbe57a917a0ba24bf1f526387e6e43a">step</a> = channels * <a class="code" href="group___p_c_m___helpers.html#gaa3e0ff7560342e5af2b5c7bd2d63a307" title="Return bits needed to store a PCM sample.">snd_pcm_format_physical_width</a>(format);
}
err = transfer_methods[method].transfer_loop(handle, samples, areas);
<span class="keywordflow">if</span> (err < 0)
printf(<span class="stringliteral">"Transfer failed: %s\n"</span>, <a class="code" href="group___error.html#ga182bbadf2349e11602bc531e8cf22f7e" title="Returns the message for an error code.">snd_strerror</a>(err));
free(areas);
free(samples);
<a name="a66"></a><a class="code" href="group___p_c_m.html#ga042aba7262a4cbb4d444b6fc08cb7124" title="close PCM handle">snd_pcm_close</a>(handle);
<span class="keywordflow">return</span> 0;
}
</pre></div> </div>
<!--- window showing the filter options -->
<div id="MSearchSelectWindow"
onmouseover="return searchBox.OnSearchSelectShow()"
onmouseout="return searchBox.OnSearchSelectHide()"
onkeydown="return searchBox.OnSearchSelectKey(event)">
<a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(0)"><span class="SelectionMark"> </span>All</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(1)"><span class="SelectionMark"> </span>Data Structures</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(2)"><span class="SelectionMark"> </span>Files</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(3)"><span class="SelectionMark"> </span>Functions</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(4)"><span class="SelectionMark"> </span>Variables</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(5)"><span class="SelectionMark"> </span>Typedefs</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(6)"><span class="SelectionMark"> </span>Enumerations</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(7)"><span class="SelectionMark"> </span>Enumerator</a><a class="SelectItem" href="javascript:void(0)" onclick="searchBox.OnSelectItem(8)"><span class="SelectionMark"> </span>Defines</a></div>
<!-- iframe showing the search results (closed by default) -->
<div id="MSearchResultsWindow">
<iframe src="" frameborder="0"
name="MSearchResults" id="MSearchResults">
</iframe>
</div>
<hr class="footer"/><address style="text-align: right;"><small>Generated on Sat Nov 20 07:42:23 2010 for ALSA project - the C library reference by
<a href="http://www.doxygen.org/index.html">
<img class="footer" src="doxygen.png" alt="doxygen"/></a> 1.6.3 </small></address>
</body>
</html>
