在析构函数中加入boost::thread实例

类声明(为了简洁起见,我去掉了try/catch的run()方法:根据boostthread文档,无论有没有它,结果都应该相同):

class B 
{
public:
    void operator()(){run();}
    void run();
    void shutdown();
    ~B();
    B();
    boost::thread *thr;
    bool shutdown_requested;
};

void B::shutdown()
{
    shutdown_requested = true;

    if (thr != NULL)
    {
        thr->interrupt();
        thr->join(); // deadlock occurs here!
        delete thr;
        thr = NULL;
    }
}

B::~B()
{
    shutdown();
}

B::B()
{
    thr = new boost::thread(boost::ref(*this));
}

void B::run()
{
    while (!shutdown_requested)
    {
        boost::xtime xt;
        boost::xtime_get(&xt, boost::TIME_UTC);
        xt.sec += 30;
        boost::this_thread::sleep(xt);
    }
}

不起作用的代码段:

int main()
{
    B *b = new B;

    Sleep(5000);
    printf("deleting \n");fflush(stdout);
//    b->shutdown();
    delete b;
    printf("done\n");fflush(stdout);

    return 0;
}

有效的代码段:

int main()
{
    B *b = new B;

    Sleep(5000);
    printf("deleting \n");fflush(stdout);
    b->shutdown();
    delete b;
    printf("done\n");fflush(stdout);

    return 0;
}

所引用的对象的寿命超过 新创建的执行线程。