c++ - 在 libpthread 链接的应用程序中捕获异常时出现段错误(linux、C++)

Question

我这里有这段代码:

这些是用于创建和停止 pthread 的函数:

void WatchdogController::conscious_process_handler_start() {

    if ( debug ) cout << "WatchdogController: starting conscious process thread" << endl;

    cn_pr_thread_active = true;

    if ( pthread_create( &cn_pr_thread, NULL, conscious_process_handler, this ) < 0 ) {
        cn_pr_thread_active = false;
        throw WatchdogException( "Unable to start new thread" );
    }
}

void WatchdogController::conscious_process_handler_stop() {

    if ( debug ) cout << "WatchdogController: stopping conscious process thread" << endl;

    cn_pr_thread_active = false;

    int *retval;

    pthread_join( cn_pr_thread, ( void ** )&retval );

    if ( *retval < 0 ) {
        delete retval;
        string err = string( "Error returned by conscious_process_handler(): " ) + string( pthread_err );
        throw WatchdogException( err.c_str() );
    }

    delete retval;
}

我在传递给 pthread 的函数中使用 select()，当它停止时返回一个错误，导致 pthread 的返回值为负，但这不是问题，我稍后会修复它 - 问题是，当异常被扔在这里:

throw WatchdogException( err.c_str() );

并在这里捕获:

try {
        watchdog_controller->hardware_watchdog_stop();
        watchdog_controller->unconscious_process_handler_stop();
        watchdog_controller->conscious_process_handler_stop();
    }
    catch ( HardwareWatchdogException &e ) {
        cerr << "Error stopping hardware watchdog!" << endl;
        cerr << e.get_reason() << endl;
        string err = string( "Exception thrown by hardware watchdog controller" ) + string( e.get_reason() );
        if ( log ) write_log( err.c_str() );
        delete watchdog_controller;
        return -1;
    }
    catch ( WatchdogException &e ) {
        cerr << "Exception cought when exiting!" << endl;
        cerr << e.get_reason() << endl;
        string err = string( "Exception cought when exiting" ) + string( e.get_reason() );
        if ( log ) write_log( err.c_str() );
        delete watchdog_controller;
        return -1;
    }

此时我尝试访问对象时出现段错误:

cerr << e.get_reason() << endl;

可能是什么原因？

Reference &e 指向某物，但地址似乎无效。

这是异常类:

class WatchdogException {

    public:

        /**
            @brief      Default constructor
        */
        WatchdogException() : reason() {
        }

        /**
            @brief      Overloaded constructor - setting the error message
            @param      why         Error message
        */
        WatchdogException( const char *why ) : reason( why ) {
        }

        /**
            @brief      The destructor
        */
        virtual ~WatchdogException() {
        }

        /**
            @brief      A getter for the error message
            @return     Returns a string containing error description
        */
        virtual std::string get_reason() const {
            return reason;
        }

    protected:

        /**
            @var        reason      String containing the error message
        */
        std::string reason;

};

Answer 1

我猜测您没有为 retval 正确分配内存，或者您以某种方式从 cn_pr_thread 返回了一个无效指针，这就是为什么在调用 时出现段错误的原因pthread_join。