問題程式碼如下：

#include<iostream>  
#include<iomanip>  
using namespace std;  

#include <boost/thread.hpp>    
#include <boost/bind.hpp>    
#include <boost/thread/mutex.hpp>    
using namespace boost;  

typedef boost::mutex CMutex;  
typedef boost::lock_guard<CMutex> CLockGuardMutex;  
typedef boost::thread_group CThreadGroup;  


void main()
{
	CMutex oMutex;
	cout << "First Lock......" << endl;
	oMutex.lock();
	cout << "Second Lock......" << endl;
	oMutex.lock();
	cout << "Unlock Once......" << endl;
	oMutex.unlock();
	cout << "Unlock Twice......" << endl;
	oMutex.unlock();
}