event dispatcher using std::unique_ptr and std::deque in c++11 - c++

Question

I have just written the source code below to dispatch events properly by using std::unique_ptr and std::deque, but I am not sure how accurate it is. I know it is not a good question but could someone evaluate it, is there any weird issue? In addition, I don't have any performance concern.
Thanks in advance.
- Volkan
#include <iostream>
#include <deque>
#include <mutex>
#include <memory>
#include <chrono>
#include <thread>
using namespace std;
class Event {
public:
Event(int a) : m_a(a)
{ }
void print()
{
cout << m_a << endl;
}
private:
int m_a;
};
class EventQueue {
public:
unique_ptr<Event> pop()
{
lock_guard<mutex> lock(m_Mutex);
unique_ptr<Event> p = nullptr;
if (!m_Queue.empty()) {
p = move(m_Queue.back());
m_Queue.pop_back();
}
return p;
}
void push(unique_ptr<Event> p)
{
lock_guard<mutex> lock(m_Mutex);
m_Queue.push_front(move(p));
}
private:
deque<unique_ptr<Event>> m_Queue;
mutex m_Mutex;
};
EventQueue evq;
void EventHandler()
{
while (true) {
unique_ptr<Event> p = evq.pop();
if (p)
p->print();
else
this_thread::sleep_for(chrono::seconds(10));
}
}
int main()
{
std::thread first (EventHandler);
while (true) {
int a;
cin >> a;
unique_ptr<Event> ev(new Event(a));
evq.push(move(ev));
}
first.join();
return 0;
}