1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
|
#include "SSVLSystemAlertVolume.h"
const AudioServicesPropertyID SSVLAudioServicesPropertySystemAlertVolume = 'ssvl';
OSStatus SSVLGetSystemVolume(Float32 *volume) {
UInt32 volume_size = sizeof(*volume);
OSStatus result = AudioServicesGetProperty(
kAudioServicesPropertySystemAlertVolume,
0,
NULL,
&volume_size,
volume
);
// TODO: Sound PrefPane: If result != noErr, return 0.5?
if (*volume != 0) {
*volume = log(*volume) + 1.0;
}
else {
*volume = 0;
}
return result;
}
OSStatus SSVLSetSystemVolume(Float32 volume) {
volume = exp(volume - 1.0);
return AudioServicesSetProperty(
kAudioServicesPropertySystemAlertVolume,
0,
NULL,
sizeof(volume),
&volume
);
}
int main() {
OSStatus result;
Float32 volume;
result = system_volume_get(&volume);
if (result != noErr) {
printf("Error getting system volume: %d\n", result);
return 1;
}
printf("System volume: %f\n", volume);
Float32 new_volume = 0.5;
result = system_volume_set(new_volume);
if (result != noErr) {
printf("Error setting system volume: %d\n", result);
return 1;
}
printf("Set volume to: %f\n", new_volume);
}
|
