destruction guards?

gistfile1.txt

class Periodic {
public:
	Periodic(io_service& io):io_(io), timer_(io){}
	
	// thread-unsafe
	void addName(string name){ 
		names_.push_back(name);
	}

	// thread-safe
	void addNameTS(string name){
		io_.dispatch([this](){
			names_.push_back(name);
		});
	}

	void start(){ setupTimer(30); }

private:
	io_service& io_;
	steady_timer timer_;
	vector<string> names_;

	void setupTimer(double rate)
	{
		timer_.expires_from_now(milliseconds(1000/rate));
		timer_.async_wait([this](error_code& code){
			if (code != error::operation_aborted)
			{
				printNames();
				setupTimer();
			}
		});
	}

	void printNames()
	{
		for (auto name:names_)
			cout << "hello, " << name << endl;
	}
}