Self owned class using std::shared_ptr. Destroys itself after work() is done.

self_owned.cpp

#include <memory>
#include <iostream>
#include <unistd.h>
#include <thread>
using namespace std;

class a: public std::enable_shared_from_this<a>
{
    std::shared_ptr<a> self;
public:
	//a() {cout << "ctor" << endl;}
	a(): self(this) {cout << "ctor" << endl;}
	~a() {cout << "dtor" << endl;}
	std::shared_ptr<a> getPtr() {return shared_from_this();}
	void destroy() {self.reset();}
	void work() {cout << "sleep" << endl; sleep(3); cout <<"wake"<<endl; destroy();}
};

int main() {
	cout << "1" << endl;
	a *tmp = new a;
	std::shared_ptr<a> pa = tmp->getPtr();
	tmp = 0;
	cout << "2" << endl;
	std::thread th(std::bind(&a::work, pa.get()));
	pa.reset();
	cout << "3" << endl;
	th.join();
    cout << "4" << endl;
	return 0;
}