程序如下，运行后，音量还是一样不变，请问怎样才能使通过程序使音量变小？谢谢
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <linux/soundcard.h>
main()
{
int MIX_FD;
int iLeft = 20;
int iRight = 20;
int iLevel;
iLevel = (iRight << 8) + iLeft;
MIX_FD= open("/dev/mixer", O_WRONLY);
if (MIX_FD == -1) {
perror("Error:open /dev/mixer error");
exit(1);
}
if (ioctl(MIX_FD, MIXER_READ(SOUND_MIXER_VOLUME), &iLevel) == -1) {
perror("Error:MIXER_WRITE ioctl failed");
exit(1);
}
if (ioctl(MIX_FD, MIXER_READ(SOUND_MIXER_VOLUME), &iLevel) == -1) {
perror("Error:MIXER_WRITE ioctl failed");
exit(1);
}
close(MIX_FD);
}
