一种有效避免死锁的互斥锁设计

#ifndef MUTEX_LOCK_H
#define MUTEX_LOCK_H

#ifndef WIN32
#include <windows.h>
#endif

#ifdef __unix
#include <pthread.h>
#endif // __unix


class Mutex
{
public:
	Mutex();
	~Mutex();

	void Lock();

	void Unlock();

private:
	Mutex(const Mutex&);
	void operator=(const Mutex&);

#ifdef WIN32
	CRITICAL_SECTION m_mutex;
#endif // WIN32

#ifdef __unix
	pthread_mutex_t m_mutex;
#endif // __unix	
};


class MutexLock
{
public:
	explicit MutexLock(Mutex *mutex) :m_mutex(mutex)
	{
		m_mutex->Lock();
	};
	~MutexLock()
	{ 
		m_mutex->Unlock(); 
	};

private:
	// 不允许复制
	MutexLock(const MutexLock&);
	void operator=(const MutexLock&);

	Mutex *m_mutex;
};


#endif // !MUTEX_LOCK_H

#include "mutex.h"

Mutex::Mutex()
{
#ifdef WIN32
	InitializeCriticalSection(&m_mutex);
#endif
#ifdef __unix
	pthread_mutex_init(&m_mutex, NULL);
#endif // __unix
}

Mutex::~Mutex()
{
#ifdef WIN32
	DeleteCriticalSection(&m_mutex);
#endif
	
#ifdef __unix
	pthread_mutex_destroy(&m_mutex);
#endif // __unix
}

void Mutex::Lock()
{
#ifdef WIN32
	EnterCriticalSection(&m_mutex);
#endif
#ifdef __unix
	pthread_mutex_lock(&m_mutex);
#endif // __unix
}

void Mutex::Unlock()
{
#ifdef WIN32
	LeaveCriticalSection(&m_mutex);
#endif
#ifdef __unix
	pthread_mutex_unlock(&m_mutex);
#endif // __unix
}

Mutex mutex;

void MutexTest()
{
	MutexLock l(&mutex);
	static int  i = 0;
	printf("i = %d\n", i);
	++i;
}