threadsafe stack

/****************************************************************************
@File Name: safestack.h
@Author: wangzhicheng
@mail: 2363702560@qq.com
@Created Time: Wed 08 Mar 2017 09:06:48 AM CST
****************************************************************************/
#include <atomic>
#include <memory>
#include <mutex>
#include <stack>
namespace safestack
{
using namespace std;
template<typename T>
class SafeStack
{
private:
	const int m_nlimit;
	atomic_int m_total;
	stack<T>m_data;
	mutable mutex m_mutex;
public:
	SafeStack(int n = 1000):m_nlimit(n)
	{
		m_total = 0;
	}
	SafeStack(const SafeStack &other)
	{
		lock_guard<mutex>lock(other.m_mutex);
		m_data = other.data;
	}
	SafeStack & operator =(const SafeStack&) = delete; 
	bool push(T value)
	{
		if(m_total >= m_nlimit) return false;
		++m_total;
		lock_guard<mutex>lock(m_mutex);
		m_data.push(value);

		return true;
	}
	shared_ptr<T>pop()
	{
		lock_guard<mutex>lock(m_mutex);
		if(m_data.empty()) return nullptr;
		--m_total;
		shared_ptr<T>const res(make_shared<T>(m_data.top()));
		m_data.pop();

		return res;
	}
	bool pop(T &value)
	{
		lock_guard<mutex>lock(m_mutex);
		if(m_data.empty()) return false;
		--m_total;
		value = m_data.top();
		m_data.pop();

		return true;
	}
	bool empty() const
	{
		lock_guard<mutex>lock(m_mutex);
		return m_data.empty();
	}
};
}

/****************************************************************************
@File Name: test.cpp
@Author: wangzhicheng
@mail: 2363702560@qq.com
@Created Time: Wed 08 Mar 2017 09:09:30 AM CST
****************************************************************************/
#include "safestack.h"
#include <iostream>
#include <thread>
using namespace safestack;
static const int N = 1000000;
SafeStack<int>ss(N);
void thread_push()
{
	while(1)
	{
		for(int i = 0;i < N;i++) ss.push(i);
	}
}
void thread_pop()
{
	while(1)
	{
		shared_ptr<int>ptr = ss.pop();
		if(!ptr) cout << "stack is empty...!" << endl;
	}
}
int main()
{
	thread th0(thread_push);
	thread th1(thread_pop);
	th0.join();
	th1.join();

	return 0;
}

CC=g++
all:
	$(CC) -std=c++11 -g -o safestackTest test.cpp safestack.h -pthread