IOS修改系统音量

#import <IOKit/IOKitLib.h>
#import <IOKit/hidsystem/IOHIDLib.h>
#import <IOKit/hidsystem/ev_keymap.h>
 
static io_connect_t get_event_driver(void)
{
    static  mach_port_t        sEventDrvrRef = 0;
    mach_port_t                masterPort, service, iter;
    kern_return_t            kr;
     
    if (!sEventDrvrRef) {
        // Get master device port
        kr = IOMasterPort( bootstrap_port, &masterPort );
        check( KERN_SUCCESS == kr);
         
        kr = IOServiceGetMatchingServices( masterPort, IOServiceMatching(kIOHIDSystemClass), &iter );
        check( KERN_SUCCESS == kr);
         
        service = IOIteratorNext( iter );
        check( service );
         
        kr = IOServiceOpen( service, mach_task_self(), kIOHIDParamConnectType, &sEventDrvrRef );
        check( KERN_SUCCESS == kr );
         
        IOObjectRelease( service );
        IOObjectRelease( iter );
    }
     
    return sEventDrvrRef;
}
static void HIDPostAuxKeyWithState(UInt8 auxKeyCode, UInt8 keyState)
{
    NXEventData event;
    kern_return_t kr;
    IOGPoint loc = { 0, 0 };
         
    bzero(&event, sizeof(NXEventData));
    event.compound.subType = NX_SUBTYPE_AUX_CONTROL_BUTTONS;
     
    if (OSLittleEndian == OSHostByteOrder()) {
        UInt32 evtInfo = auxKeyCode << 16 | keyState << 8;
        event.compound.misc.L[0] = evtInfo;
    }else {
        event.compound.misc.S[0] = auxKeyCode;
        event.compound.misc.C[2] = keyState;
    }
     
    kr = IOHIDPostEvent( get_event_driver(), NX_SYSDEFINED, loc, &event, kNXEventDataVersion, 0, FALSE );
    check( KERN_SUCCESS == kr );
}
static void HIDPostAuxKey(UInt8 auxKeyCode)
{
    HIDPostAuxKeyWithState(auxKeyCode, NX_KEYDOWN);
    HIDPostAuxKeyWithState(auxKeyCode, NX_KEYUP);
}
使用方法：
HIDPostAuxKey(NX_KEYTYPE_SOUND_UP);