C++并发编程练习12 “在跨线程中使用函数对象（指针）”

需要谨慎防止被保护的对象意外泄露到外界函数被更改状态。代码示例如下：

#include 
#include 
#include 
#include 
#include 

struct TData
{
public:
	int n;
	std::string str;

public:
	TData()
	{
		n  = 0;
		str = "Moutain River";
	}	
};

class CDataWrapper
{
	TData data;
	std::mutex mt;
public:	
	void processData(std::function func)
	{
		mt.lock();
		func(data.n, data.str);
		mt.unlock();
	}	
};

void func(const int& n, const std::string& str)
{
	std::cout << n << std::endl;
	std::cout << str.c_str() << std::endl;
}

CDataWrapper* pdw = nullptr;

void task()
{
	if (pdw != nullptr)
		pdw->processData(func);
}

int main()
{
	CDataWrapper dw;
	pdw = &dw;
	std::thread t(task);
	t.join();
	return 0;
}