[url]http://www.alsa-project.org/alsa-doc/alsa-lib/_2test_2pcm__min_8c-example.html[/ur
l]

0001 /

00002  *  This extra small demo sends a random samples to your
speakers.
00003  */
00004
00005 #include "../include/asoundlib.h"
00006
00007 static char *device = "default";                        /*
playback device */
00008
00009 snd_output_t *output = NULL;
00010 unsigned char buffer[16*1024];                          /* some
random data */
00011
00012 int main(void)
00013 {
00014         int err;
00015         unsigned int i;
00016         snd_pcm_t *handle;
00017         snd_pcm_sframes_t frames;
00018
00019         for (i = 0; i < sizeof(buffer); i++)
00020                 buffer = random() & 0xff;
00021
00022         if ((err = snd_pcm_open(&handle, device,
SND_PCM_STREAM_PLAYBACK, 0)) < 0) {
00023                 printf("Playback open error: %s\n",
snd_strerror(err));
00024                 exit(EXIT_FAILURE);
00025         }
00026         if ((err = snd_pcm_set_params(handle,
00027                                       SND_PCM_FORMAT_U8,
00028
SND_PCM_ACCESS_RW_INTERLEAVED,
00029                                       1,
00030                                       48000,
00031                                       1,
00032                                       500000)) < 0) {   /*
0.5sec */
00033                 printf("Playback open error: %s\n",
snd_strerror(err));
00034                 exit(EXIT_FAILURE);
00035         }
00036
00037         for (i = 0; i < 16; i++) {
00038                 frames = snd_pcm_writei(handle, buffer,
sizeof(buffer));
00039                 if (frames < 0)
00040                         frames = snd_pcm_recover(handle, frames,
0);
00041                 if (frames < 0) {
00042                         printf("snd_pcm_writei failed: %s\n",
snd_strerror(err));
00043                         break;
00044                 }
00045                 if (frames > 0 && frames < (long)sizeof(buffer))
00046                         printf("Short write (expected %li, wrote
%li)\n", (long)sizeof(buffer), frames);
00047         }
00048
00049         snd_pcm_close(handle);
00050         return 0;a
thanks very much.

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On 3=D4=C218=C8=D5, =CF=C2=CE=E71=CA=B124=B7=D6, "DaVinci" <apple.davi...@g=
mail.com> wrote:
> http://www.alsa-project.org/alsa-do...__min_8c-exa...
>
> 0001 /
>
> 00002  *  This extra small demo sends a random samples to your
> speakers.
> 00003  */
> 00004
> 00005 #include "../include/asoundlib.h"
> 00006
> 00007 static char *device =3D "default";                        /*
> playback device */
> 00008
> 00009 snd_output_t *output =3D NULL;
> 00010 unsigned char buffer[16*1024];                          /* some
> random data */
> 00011
> 00012 int main(void)
> 00013 {
> 00014         int err;
> 00015         unsigned int i;
> 00016         snd_pcm_t *handle;
> 00017         snd_pcm_sframes_t frames;
> 00018
> 00019         for (i =3D 0; i < sizeof(buffer); i++)
> 00020                 buffer =3D random() & 0xff;
> 00021
> 00022         if ((err =3D snd_pcm_open(&handle, device,
> SND_PCM_STREAM_PLAYBACK, 0)) < 0) {
> 00023                 printf("Playback open error: %s\n",
> snd_strerror(err));
> 00024                 exit(EXIT_FAILURE);
> 00025         }
> 00026         if ((err =3D snd_pcm_set_params(handle,
> 00027                                       SND_PCM_FORMAT_U8,
> 00028
> SND_PCM_ACCESS_RW_INTERLEAVED,
> 00029                                       1,
> 00030                                       48000,
> 00031                                       1,
> 00032                                       500000)) < 0) {   /*
> 0.5sec */
> 00033                 printf("Playback open error: %s\n",
> snd_strerror(err));
> 00034                 exit(EXIT_FAILURE);
> 00035         }
> 00036
> 00037         for (i =3D 0; i < 16; i++) {
> 00038                 frames =3D snd_pcm_writei(handle, buffer,
> sizeof(buffer));
> 00039                 if (frames < 0)
> 00040                         frames =3D snd_pcm_recover(handle, frames,
> 0);
> 00041                 if (frames < 0) {
> 00042                         printf("snd_pcm_writei failed: %s\n",
> snd_strerror(err));
> 00043                         break;
> 00044                 }
> 00045                 if (frames > 0 && frames < (long)sizeof(buffer))
> 00046                         printf("Short write (expected %li, wrote
> %li)\n", (long)sizeof(buffer), frames);
> 00047         }
> 00048
> 00049         snd_pcm_close(handle);
> 00050         return 0;a
> thanks very much.

I have solved the problem .Thanks.

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