Register a callback for all multitouch devices

gistfile1.m

static NSArray* devices;

void startMT(){
  devices = CFBridgingRelease(MTDeviceCreateList());
  for(int i = 0; i < devices.count; i++)
  {
    MTDeviceRef device = (__bridge MTDeviceRef)devices[i];
    MTRegisterContactFrameCallback(device, mtcallback);
    MTDeviceStart(device, 0);
  }
}

void stopMT(){
  for(int i = 0; i < devices.count; i++)
  {
    MTDeviceRef device = (__bridge MTDeviceRef)devices[i];
    MTDeviceStop(device);
  }
  devices = nil;
}