Hi, I am new to ALSA. I am trying to write a program that will generate waves on user input of different parameters. With the code I have written(below), I am unable to generate a sine wave. Any help would be greatly appreciated.
#include <stdio.h>
#include <stdlib.h>
#include <alsa/asoundlib.h>
#include <math.h>

main (int argc, char *argv[])
{
int i;
int err;
int t;
int buf[128];
snd_pcm_t *playback_handle;
snd_pcm_hw_params_t *hw_params;

if ((err = snd_pcm_open (&playback_handle, argv[1],
SND_PCM_STREAM_PLAYBACK, 0)) < 0) {
fprintf (stderr, "cannot open audio device %s (%s)\n",
argv[1],
snd_strerror (err));
exit (1);
}

if ((err = snd_pcm_hw_params_malloc (&hw_params)) < 0) {
fprintf (stderr, "cannot allocate hardware parameter structure (%s)\n",
snd_strerror (err));
exit (1);
}

if ((err = snd_pcm_hw_params_any (playback_handle, hw_params)) < 0) {
fprintf (stderr, "cannot initialize hardware parameter structure (%s)\n",
snd_strerror (err));
exit (1);
}

if ((err = snd_pcm_hw_params_set_access (playback_handle, hw_params,
SND_PCM_ACCESS_RW_INTERLEAVED)) < 0) {
fprintf (stderr, "cannot set access type (%s)\n",
snd_strerror (err));
exit (1);
}

if ((err = snd_pcm_hw_params_set_format (playback_handle, hw_params,
SND_PCM_FORMAT_S32_LE)) < 0) {
fprintf (stderr, "cannot set sample format (%s)\n",
snd_strerror (err));
exit (1);
}

int rate = 96000;
if ((err = snd_pcm_hw_params_set_rate_near (playback_handle, hw_params,
&rate, 0)) < 0) {
fprintf (stderr, "cannot set sample rate (%s)\n",
snd_strerror (err));
exit (1);
}

if ((err = snd_pcm_hw_params_set_channels (playback_handle, hw_params, 2))
< 0) {
fprintf (stderr, "cannot set channel count (%s)\n",
snd_strerror (err));
exit (1);
}

if ((err = snd_pcm_hw_params (playback_handle, hw_params)) < 0) {
fprintf (stderr, "cannot set parameters (%s)\n",
snd_strerror (err));
exit (1);
}

snd_pcm_hw_params_free (hw_params);

if ((err = snd_pcm_prepare (playback_handle)) < 0) {
fprintf (stderr, "cannot prepare audio interface for use (%s)\n",
snd_strerror (err));
exit (1);
}

for (t=0; t<128; t++ ) {
buf[t] = 0.000001 * sin( 2 * 3.14159 *11 / 128 * t ) ;
}
while( 1 ) {
if ((err = snd_pcm_writei (playback_handle, buf, 128)) != 128) {
fprintf (stderr, "write to audio interface failed (%s)\n",
snd_strerror (err));
exit (1);
}
}

snd_pcm_close (playback_handle);
exit (0);
}