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#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <unistd.h>
#include <sys/soundcard.h>
#include <time.h>
int main(void)
{
int fd = open("/dev/dsp", O_RDONLY);
if (fd == -1) { perror("open"); exit(127); }
int res = AFMT_S16_LE;
if (ioctl(fd, SNDCTL_DSP_SETFMT, &res) == -1) {
perror("ioctl"); exit(127); }
res = 0;
if (ioctl(fd, SNDCTL_DSP_STEREO, &res) == -1) {
perror("ioctl"); exit(127); }
res = 22050;
if (ioctl(fd, SOUND_PCM_READ_RATE, 0xbfffdcfc) == -1) {
perror("ioctl"); exit(127); }
res = 0x2000a;
if (ioctl(fd, SNDCTL_DSP_SETFRAGMENT, &res) == -1) {
perror("ioctl"); exit(127); }
audio_buf_info info;
if (ioctl(fd, SNDCTL_DSP_GETISPACE, &info) == -1) {
perror("read"); exit(127); }
printf(" Size of a fragment in bytes: %d\n", info.fragsize);
printf(" Allocated fragments for buffering: %d\n", info.fragstotal);
char buf[1024];
if (read(fd, buf, sizeof(buf)) < 0) { perror("read"); exit(127); }
static struct timespec naptime = { 0, 100000000 };
int count = 0;
do {
if (ioctl(fd, SNDCTL_DSP_GETISPACE, &info) == -1) {
perror("read"); exit(127); }
nanosleep(&naptime, 0);
if (++count == 20) { printf("Failed to cause an xrun.\n"); exit(127); }
printf("info.bytes = %u, info.fragsize = %u, info.fragstotal = %u\n", info.bytes, info.fragsize, info.fragstotal);
} while(info.bytes < info.fragsize * info.fragstotal);
printf(" Successfully caused an xrun.\n");
printf(" non-blocking fragments: %d\n", info.fragments);
printf(" non-blocking bytes: %d\n", info.bytes);
ssize_t bufsize = info.bytes;
ssize_t trlen = 0;
int nf = 0;
for (;;)
{
if (ioctl(fd, SNDCTL_DSP_GETISPACE, &info) == -1) {
perror("ioctl"); exit(127); }
if (info.fragments > 0) {
ssize_t rlen;
if ((rlen = read(fd, buf, sizeof(buf))) < 0)
{ perror("read"); exit(127); }
trlen += rlen;
if (trlen > bufsize) {
printf(" Read %d bytes: stream successfully restarted.\n", trlen);
exit(0);
}
nf = 0;
}
else if (++nf > 10) {
printf(" Stream is not restarted after xrun.\n");
exit(1);
}
}
close(fd);
return 0;
}
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