vector< shared_ptr<Session> > hw_sessions;
// Make a list of all sessions where a hardware device is used
- for (shared_ptr<Session> s : sessions_) {
+ for (const shared_ptr<Session>& s : sessions_) {
shared_ptr<devices::HardwareDevice> hw_device =
dynamic_pointer_cast< devices::HardwareDevice >(s->device());
if (!hw_device)