Question

如果我改变变量定义的顺序，我的程序会崩溃，有人知道为什么吗？按此顺序，它将按照我的预期运行：

class xThread
{
public:  
    xThread();
    virtual ~xThread() {}

    bool thread_start();
    virtual bool thread_init(){return true;}
    virtual void thread_stop();

    void thread_setState(ThreadState s) {state = s;} 
    ThreadState thread_getState( ){return state;}

    static void *thread_run(void *param);
    void setName(const char *n);
    char name[MAX_NAMESIZE];

protected:
    volatile ThreadState state;
    virtual void thread_proc()=0;

private:
    pthread_t pid;
};

如果我改变变量的定义顺序＆＃34; name＆＃34;和＆＃34;州＆＃34;，它会崩溃：

class xThread
{
public: 
    xThread();
    virtual ~xThread() {}

    bool thread_start();
    virtual bool thread_init(){return true;}
    virtual void thread_stop();

    void thread_setState(ThreadState s) {state = s;} 
    ThreadState thread_getState( ){return state;}

    static void *thread_run(void *param);
    void setName(const char *n);

protected:
    volatile ThreadState state;
    virtual void thread_proc()=0;

private:
    pthread_t pid;
    char name[MAX_NAMESIZE];
};

这是gdb堆栈，看起来很奇怪

0  0x00007f34dfaeff72 in _int_malloc () from /lib64/libc.so.6
1  0x00007f34dfaf187c in malloc () from /lib64/libc.so.6
2  0x00007f34e03aa0cd in operator new(unsigned long) () from /lib64/libstdc++.so.6
3  0x00007f34e15d93b1 in log4cxx::Logger::forcedLog(log4cxx::helpers::ObjectPtrT<log4cxx::Level> const&, std::string const&, log4cxx::spi::LocationInfo const&) const () from /lib64/liblog4cxx.so.10
4  0x000000000081e615 in xServer::v_final (this=0x19921b0) at xlib/xServer.cpp:112
5  0x000000000082218c in xServer::run (this=0x19921b0) at xlib/xServer.cpp:411
6  0x00000000007b2ebc in main (argc=4, argv=0x7fff46d5f258) at SceneServer.cpp:152

＆＃34;名称＆＃34;是一个变量，我用来标记每个线程。它是在线程启动之前定义的，并在线程终止时打印。

main.cpp中：

    HttpClientThread client;
    client.setName("HttpClientThread ");
    client.thread_start();

xThread.cpp：

xThread::xThread()
{
    thread_setState(THREAD_INIT);
    bzero(name, sizeof(name));
    pid = 0;
}

xThread::~xThread()
{
    LOG4CXX_DEBUG(::log4cxx::Logger::getLogger("main"), name);
}

void xThread::setName(const char *n) 
{
    if (!n) return;
    bzero(name, sizeof(name));
    strncpy(name, n, MAX_NAMESIZE-1);
}

bool xThread::thread_start()
{
    if (!thread_init()) return false;

    int ret = pthread_create(&pid, NULL, &thread_run, (void *)this);
    if (ret == 0)
    {   
        return true;
    }   
    else
    {   
        return false;
    }   
}

void xThread::thread_stop()
{
    if (thread_getState()==THREAD_INIT)
        thread_setState(THREAD_FINISH);

    if (thread_getState()==THREAD_RUN)
        thread_setState(THREAD_STOP);
}

void *xThread::thread_run(void *param)
{
    xThread *t = (xThread *)param;
    t->thread_proc();
    t->thread_setState(THREAD_FINISH);
    return 0;
}

Answer 1

您不仅更改了订单。名字变得私密。我在这个课堂上看不到任何“名字”的用法。它应该至少受到保护吗？

以不同顺序定义变量会导致崩溃

1 个答案: