components/volume.c
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/* See LICENSE file for copyright and license details. */
#if defined(__linux__)
#include <errno.h>
#include <fcntl.h>
#include <sys/soundcard.h>
#include <sys/ioctl.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include "../util.h"
const char *
vol_perc(const char *card)
{
unsigned int i;
int v, afd, devmask;
char *vnames[] = SOUND_DEVICE_NAMES;
afd = open(card, O_RDONLY | O_NONBLOCK);
if (afd == -1) {
fprintf(stderr, "open '%s': %s\n", card, strerror(errno));
return NULL;
}
if (ioctl(afd, SOUND_MIXER_READ_DEVMASK, &devmask) == -1) {
fprintf(stderr, "ioctl 'SOUND_MIXER_READ_DEVMASK': %s\n", strerror(errno));
close(afd);
return NULL;
}
for (i = 0; i < LEN(vnames); i++) {
if (devmask & (1 << i) && !strcmp("vol", vnames[i])) {
if (ioctl(afd, MIXER_READ(i), &v) == -1) {
fprintf(stderr, "ioctl 'MIXER_READ(%d)': %s\n", i, strerror(errno));
close(afd);
return NULL;
}
}
}
close(afd);
return bprintf("%d", v & 0xff);
}
#endif