Re: destroy singleton?

From:
Ron Eggler <test@example.com>
Newsgroups:
comp.lang.c++
Date:
Thu, 10 Apr 2008 23:26:33 GMT
Message-ID:
<JmxLj.58853$_v3.38227@edtnps90>
Andy Champ wrote:

Ron Eggler wrote:

Thank you for hints & suggestions!
Ron


In the code you've supplied, you haven't initialised pinstance. Either
we're missing something - or you are... Also, you haven't shown what
else you do after the delete, nor what steps you take to make sure it
doesn't get deleted more than once.


i do initialize pinstance like this:
[code]
GPIOcontrol * GPIOcontrol::instance(GPSData *gpsDataObj)
{
        if (pinstance==NULL){//if this singleton hasn't been created yet...
                pinstance=new GPIOcontrol(gpsDataObj);
        }
        return pinstance;
}
[/code]

and before the delete command i check if it's "!=NULL" so that should be
fine.

What's a TSPThread?


That's a class handling threads, it just initializes and destoys the thread.
it also offers flags to check if the thread is running already.
The header looks like:
[tshpthread.h]
class TSPThread
{
public:
        ////////////////////////////////////////////////////////////////////////////////////
        /// This method check to see the thread is still active or not
        ///@return bool true thread is still running
        /// false thraed end already
        ////////////////////////////////////////////////////////////////////////////////////
        bool IsActive(){return (m_pThread == 0?false:true);};
        
        ///The entry point of the thread, after TSPThread class was create, call
this method to start the real thread
        ///This method also make sure for every TSPThread instance, there's only
one thread runs
        void start();
        
        ///Constructor
        TSPThread();
        
        ///Destructor
        virtual ~TSPThread();

        // a global flag that can be set to true by a class above to end the
thread(s)
        bool EndFlag;

protected:

        ////////////////////////////////////////////////////////////////////////////////////
        ///This method suppose to tell upper module the thread is terminated
already or not.
        ///@return true The thread is stopped already, it's safe to remove it from
memroy.
        /// false The thread is still active, please wait
        ////////////////////////////////////////////////////////////////////////////////////
        bool GetStopFlag(){return m_bStopThread;};
        
private:

        ////////////////////////////////////////////////////////////////////////////////////
        ///This is the pure virutal function, all subclass should implement this
fucntion. All stuff
        ///You wanna do in the thread whould go here.
        ////////////////////////////////////////////////////////////////////////////////////
        virtual void run()=0;
        
        ////////////////////////////////////////////////////////////////////////////////////
        ///This is a helper function for TSPThread, it makes class TSPThread know
nothing about
        ///subclass, but subclass keeps all features as a normal class.
        ///@param void *i_ptr The pointer of current subclass object
        ///@return static void * Dummy type for pthread_create
        ////////////////////////////////////////////////////////////////////////////////////
        static void *StartThread(void *i_ptr);
        
        ///The flag for thread is created already or not
        bool m_bThreadAlready;
        
        ///Flag forcurrent thread is stopped or not
        bool m_bStopThread;
        
        ///The handler for current thread
        pthread_t m_pThread;
        
        ///Mutex for thread creation critical section
        pthread_mutex_t mutex_single;
        
        
};
[/tshpthread.h]

--
weeks of software engineering safe hours of planning ;)

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