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Watchdog class

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  • jsulmJ jsulm

    @SPlatten said in Watchdog class:

    The parameter is the expiry time to use for the timer.

    The question was about QObject* pParent parameter... Setting an instance of another class as parent is indeed strange.

    Why is QTimer* mptmrExpiry actually a pointer? Why not a simple member variable?

    SPlattenS Offline
    SPlattenS Offline
    SPlatten
    wrote on last edited by
    #7

    @jsulm It certainly could be.

    Kind Regards,
    Sy

    1 Reply Last reply
    0
    • SPlattenS SPlatten

      @KroMignon , have you looked at the source?

      • why do you have a parent parameter for setExpiry()?
        The parameter is the expiry time to use for the timer.

      • your destructor() also looks strange to me!
        Why? It cleans up stopping any started time and disconnects the connection.

      • why not simply call QTimer::start() in kick()??
        Thats exactly what it does, it calls an overloaded version of QTimer::start passing the time to it.

      • why do you not use clsWatchdog instance as parent for the QTimer instance? This will ensure timer would be stopped and destroyed when clsWatchdog is destroyed.
        I've had a better idea today which I'm going to implement. Will post back when I've completed it.

      KroMignonK Offline
      KroMignonK Offline
      KroMignon
      wrote on last edited by KroMignon
      #8

      @SPlatten said in Watchdog class:

      have you looked at the source?

      Yes I do.
      But you don't take in account my remarks.
      As usual, you always over-engineering your implementation without taking documentation in account and doing stuff because you suppose how it works but not taking time to learn how it really works.

      QObject class/sub-classes mostly have a parent parameter to simplify memory and threading management. You should already know this.
      Defining an external parent for the QTimer in clsWatchdog do not made sense. If you want to define a parent, the class instance should be the parent!

      When calling QTimer::start(), as written in documentation, the QTimer instance will be (re)started with default interval (defined with QTimer::setInterval()), so why do you do this?:

              auto durMS = std::chrono::milliseconds(mptmrExpiry->interval());
              mptmrExpiry->start(durMS);
      

      It is an old maxim of mine that when you have excluded the impossible, whatever remains, however improbable, must be the truth. (Sherlock Holmes)

      SPlattenS 1 Reply Last reply
      2
      • KroMignonK KroMignon

        @SPlatten said in Watchdog class:

        have you looked at the source?

        Yes I do.
        But you don't take in account my remarks.
        As usual, you always over-engineering your implementation without taking documentation in account and doing stuff because you suppose how it works but not taking time to learn how it really works.

        QObject class/sub-classes mostly have a parent parameter to simplify memory and threading management. You should already know this.
        Defining an external parent for the QTimer in clsWatchdog do not made sense. If you want to define a parent, the class instance should be the parent!

        When calling QTimer::start(), as written in documentation, the QTimer instance will be (re)started with default interval (defined with QTimer::setInterval()), so why do you do this?:

                auto durMS = std::chrono::milliseconds(mptmrExpiry->interval());
                mptmrExpiry->start(durMS);
        
        SPlattenS Offline
        SPlattenS Offline
        SPlatten
        wrote on last edited by
        #9

        @KroMignon, kick function is supposed to restart the timer keeping it from timing out, it calls the timer interval method in order to get the interval that was originally set so it can restart the timer with it.

        Kind Regards,
        Sy

        aha_1980A jsulmJ KroMignonK 3 Replies Last reply
        0
        • SPlattenS SPlatten

          @KroMignon, kick function is supposed to restart the timer keeping it from timing out, it calls the timer interval method in order to get the interval that was originally set so it can restart the timer with it.

          aha_1980A Offline
          aha_1980A Offline
          aha_1980
          Lifetime Qt Champion
          wrote on last edited by
          #10

          @SPlatten said in Watchdog class:

          @KroMignon, kick function is supposed to restart the timer keeping it from timing out, it calls the timer interval method in order to get the interval that was originally set so it can restart the timer with it.

          So have your read https://doc.qt.io/qt-5/qtimer.html#start-1 ?

          Starts or restarts the timer with the timeout specified in interval.

          If the timer is already running, it will be stopped and restarted.

          So mptmrExpiry->start(); is enought for your need.

          Regards

          Qt has to stay free or it will die.

          1 Reply Last reply
          1
          • SPlattenS SPlatten

            @KroMignon, kick function is supposed to restart the timer keeping it from timing out, it calls the timer interval method in order to get the interval that was originally set so it can restart the timer with it.

            jsulmJ Offline
            jsulmJ Offline
            jsulm
            Lifetime Qt Champion
            wrote on last edited by
            #11

            @SPlatten I will cite the documentation here:
            void QTimer::start()

            This function overloads start().

            Starts or restarts the timer with the timeout specified in interval.

            If the timer is already running, it will be stopped and restarted.

            So, there is no need to call mptmrExpiry->interval() each time you call start(). That's what @KroMignon is saying.

            https://forum.qt.io/topic/113070/qt-code-of-conduct

            1 Reply Last reply
            2
            • SPlattenS SPlatten

              @KroMignon, kick function is supposed to restart the timer keeping it from timing out, it calls the timer interval method in order to get the interval that was originally set so it can restart the timer with it.

              KroMignonK Offline
              KroMignonK Offline
              KroMignon
              wrote on last edited by
              #12

              @SPlatten said in Watchdog class:

              kick function is supposed to restart the timer keeping it from timing out, it calls the timer interval method in order to get the interval that was originally set so it can restart the timer with it.

              And this is exactly what QTimer::start() do!
              Because you are unable to read yourself documentation:

              void QTimer::start()
              This function overloads start().
              Starts or restarts the timer with the timeout specified in interval.
              If the timer is already running, it will be stopped and restarted.
              If singleShot is true, the timer will be activated only once.

              It is an old maxim of mine that when you have excluded the impossible, whatever remains, however improbable, must be the truth. (Sherlock Holmes)

              SPlattenS 1 Reply Last reply
              2
              • KroMignonK KroMignon

                @SPlatten said in Watchdog class:

                kick function is supposed to restart the timer keeping it from timing out, it calls the timer interval method in order to get the interval that was originally set so it can restart the timer with it.

                And this is exactly what QTimer::start() do!
                Because you are unable to read yourself documentation:

                void QTimer::start()
                This function overloads start().
                Starts or restarts the timer with the timeout specified in interval.
                If the timer is already running, it will be stopped and restarted.
                If singleShot is true, the timer will be activated only once.

                SPlattenS Offline
                SPlattenS Offline
                SPlatten
                wrote on last edited by SPlatten
                #13

                @KroMignon , reading something is not proof that it does what it says! The reason I posted here in the first place is because having read the documentation, it doesn't seem to do what it is documented.

                I wish you would stop playing the same old record, its very tiresome and boring, just because once I said someplace that I didn't read the documentation does not make it my life story so get over it and move on.

                For the record I have been developing and writing software since 1987 professionally, so to say I don't read is insulting and wrong.

                Kind Regards,
                Sy

                KroMignonK W 2 Replies Last reply
                0
                • SPlattenS SPlatten

                  @KroMignon , reading something is not proof that it does what it says! The reason I posted here in the first place is because having read the documentation, it doesn't seem to do what it is documented.

                  I wish you would stop playing the same old record, its very tiresome and boring, just because once I said someplace that I didn't read the documentation does not make it my life story so get over it and move on.

                  For the record I have been developing and writing software since 1987 professionally, so to say I don't read is insulting and wrong.

                  KroMignonK Offline
                  KroMignonK Offline
                  KroMignon
                  wrote on last edited by
                  #14

                  @SPlatten said in Watchdog class:

                  it doesn't seem to do what it is documented.

                  Just for the record, I am using QTimer for years now with Windows/Android/Linux system and have implemented such kind of "Watchdog timer" and I am using QTimer::start() and it simply works.

                  The only thing why QTimer do not work could be:

                  • the thread event loop is not working/locked
                  • call start()/stop() slot from the wrong thread

                  PS: I, and I suppose many of Qt forum contributors, doing software development for years/decades... This not preserve us from doing bad stuff!

                  It is an old maxim of mine that when you have excluded the impossible, whatever remains, however improbable, must be the truth. (Sherlock Holmes)

                  SPlattenS 1 Reply Last reply
                  1
                  • KroMignonK KroMignon

                    @SPlatten said in Watchdog class:

                    it doesn't seem to do what it is documented.

                    Just for the record, I am using QTimer for years now with Windows/Android/Linux system and have implemented such kind of "Watchdog timer" and I am using QTimer::start() and it simply works.

                    The only thing why QTimer do not work could be:

                    • the thread event loop is not working/locked
                    • call start()/stop() slot from the wrong thread

                    PS: I, and I suppose many of Qt forum contributors, doing software development for years/decades... This not preserve us from doing bad stuff!

                    SPlattenS Offline
                    SPlattenS Offline
                    SPlatten
                    wrote on last edited by
                    #15

                    @KroMignon , likewise I've been using instances of QTimer all over, I posted here because it seems not to be working and since everyone can make mistakes its not always obvious what has been done wrong, which was why I was hoping someone could explain why it doesn't seem to be restarting.

                    As mentioned in another post I've thought about a work around.

                    Kind Regards,
                    Sy

                    KroMignonK 1 Reply Last reply
                    0
                    • SPlattenS SPlatten

                      @KroMignon , likewise I've been using instances of QTimer all over, I posted here because it seems not to be working and since everyone can make mistakes its not always obvious what has been done wrong, which was why I was hoping someone could explain why it doesn't seem to be restarting.

                      As mentioned in another post I've thought about a work around.

                      KroMignonK Offline
                      KroMignonK Offline
                      KroMignon
                      wrote on last edited by
                      #16

                      @SPlatten said in Watchdog class:

                      As mentioned in another post I've thought about a work around.

                      This would be my suggestion (maybe there are some typo):

                      class clsWatchdog : public QObject 
                      {
                          Q_OBJECT
                      
                      private:
                          QTimer* mptmrExpiry;
                      
                      public:
                          explicit clsWatchdog(int interval, QObject* parent = nullptr)
                          : QObject(parent)
                          , mptmrExpiry(new QTimer(this))
                          {
                              connect(mptmrExpiry, &QTimer::timeout, this, &clsWatchdog::expired);
                              mptmrExpiry->setInterval(interval);
                              mptmrExpiry->setSingleShot(true);
                              //Note: timer will NOT be started here    
                          }
                      
                          void setExpiry(quint16 uint16Expiry)
                          {
                              //Note: timer will NOT be (re)started here    
                              mptmrExpiry->setInterval(uint16Expiry);
                          }
                          
                      public slots:
                          void kick()
                          {
                              // ensure called in right thread
                              if(QThread::currentThread() != thread())
                              {
                                  QTimer::singleShot(0, this, &clsWatchdog::kick);
                                  return;
                              }
                              // start or restat the timer
                              mptmrExpiry->start();
                          }
                          void pause()
                          {
                              // ensure called in right thread
                              if(QThread::currentThread() != thread())
                              {
                                  QTimer::singleShot(0, this, &clsWatchdog::pause);
                                  return;
                              }
                              if(mptmrExpiry->isActive())
                                  mptmrExpiry->stop();
                          }
                      
                      signals:
                          void expired();
                      };
                      

                      It is an old maxim of mine that when you have excluded the impossible, whatever remains, however improbable, must be the truth. (Sherlock Holmes)

                      SPlattenS 1 Reply Last reply
                      2
                      • KroMignonK KroMignon

                        @SPlatten said in Watchdog class:

                        As mentioned in another post I've thought about a work around.

                        This would be my suggestion (maybe there are some typo):

                        class clsWatchdog : public QObject 
                        {
                            Q_OBJECT
                        
                        private:
                            QTimer* mptmrExpiry;
                        
                        public:
                            explicit clsWatchdog(int interval, QObject* parent = nullptr)
                            : QObject(parent)
                            , mptmrExpiry(new QTimer(this))
                            {
                                connect(mptmrExpiry, &QTimer::timeout, this, &clsWatchdog::expired);
                                mptmrExpiry->setInterval(interval);
                                mptmrExpiry->setSingleShot(true);
                                //Note: timer will NOT be started here    
                            }
                        
                            void setExpiry(quint16 uint16Expiry)
                            {
                                //Note: timer will NOT be (re)started here    
                                mptmrExpiry->setInterval(uint16Expiry);
                            }
                            
                        public slots:
                            void kick()
                            {
                                // ensure called in right thread
                                if(QThread::currentThread() != thread())
                                {
                                    QTimer::singleShot(0, this, &clsWatchdog::kick);
                                    return;
                                }
                                // start or restat the timer
                                mptmrExpiry->start();
                            }
                            void pause()
                            {
                                // ensure called in right thread
                                if(QThread::currentThread() != thread())
                                {
                                    QTimer::singleShot(0, this, &clsWatchdog::pause);
                                    return;
                                }
                                if(mptmrExpiry->isActive())
                                    mptmrExpiry->stop();
                            }
                        
                        signals:
                            void expired();
                        };
                        
                        SPlattenS Offline
                        SPlattenS Offline
                        SPlatten
                        wrote on last edited by SPlatten
                        #17

                        @KroMignon Very soon I will post the new version of the class, which is simpler.

                        In developing this now, I am getting lots of what I believe are wrong clazy warings, e.g.:

                            mtmrExpiry.setInterval(std::chrono::milliseconds(clsWatchdog::mscint16Timer));
                            mtmrExpiry.setSingleShot(false);
                            QObject::connect(&mtmrExpiry, &QTimer::timeout, this, &clsWatchdog::onTimeout);
                            mtmrExpiry.start();
                        

                        There is a clazy warning on the connect line:

                        QTimer::timeout is not a signal [clazy-connect-non-signal]
                        

                        What could be causing this? QTimer is defined as a member of the class, as is the slot onTimeout:

                            class clsWatchdog : public QObject {
                            Q_OBJECT
                        
                            private:
                                static const int mscint16Default;
                                static const int mscint16Timer;
                        
                                QTimer mtmrExpiry;
                           ...
                            private slots:
                                void onTimeout();
                            };
                        

                        Another clazy message:

                        Emit keyword being used with non-signal clsWatchdog::expired [clazy-incorrect-emit]
                        

                        This is on:

                        emit expired();
                        

                        Which is called in one of my class methods, there is the prototype in the class:

                            signals:
                                void expired();
                        

                        Kind Regards,
                        Sy

                        1 Reply Last reply
                        0
                        • SPlattenS Offline
                          SPlattenS Offline
                          SPlatten
                          wrote on last edited by SPlatten
                          #18

                          Here is the finished clsWatchdog which despite the clazy messages works, prototype:

                          #ifndef CLSWATCHDOG_H
                                  #define CLSWATCHDOG_H
                              
                                  #include <QTimer>
                              
                                  class clsWatchdog : public QObject {
                                  Q_OBJECT
                              
                                  private:
                                      static const int mscint16Default;
                                      static const int mscint16Timer;
                              
                                      QTimer mtmrExpiry;
                                      quint16 muint16Counter, muint16Setpoint;
                              
                                  public:
                                      explicit clsWatchdog();
                                      ~clsWatchdog();
                              
                                      void kick();
                                      void pause();
                                      void resume();
                              
                                  signals:
                                      void expired();
                              
                                  private slots:
                                      void onTimeout();
                                  };
                              #endif // CLSWATCHDOG_H
                          

                          Implementation:

                          /**
                           * File:    clsWatchdog.cpp
                           * Notes:   Contains implementation of the watchdog class
                           * History: 2021/01/14 Created by Simon Platten
                           */
                          #include "../clsDebugService.h"
                          #include "clsWatchdog.h"
                          //Static initialisation
                          const int clsWatchdog::mscint16Default = 12;    //Counter setpoint
                          const int clsWatchdog::mscint16Timer = 1000;    //Milliseconds
                          /**
                           * @brief clsWatchdog::clsWatchdog - Class constructor
                           */
                          clsWatchdog::clsWatchdog() : muint16Counter(0)
                                                     , muint16Setpoint(clsWatchdog::mscint16Default) {
                              mtmrExpiry.setInterval(std::chrono::milliseconds(clsWatchdog::mscint16Timer));
                              mtmrExpiry.setSingleShot(false);
                              QObject::connect(&mtmrExpiry, &QTimer::timeout, this, &clsWatchdog::onTimeout);
                              mtmrExpiry.start();
                          }
                          /**
                           * @brief clsWatchdog::~clsWatchdog - Class destructor
                           */
                          clsWatchdog::~clsWatchdog() {
                              if ( mtmrExpiry.isActive() == true ) {
                                  mtmrExpiry.stop();
                              }
                              QObject::disconnect(&mtmrExpiry, &QTimer::timeout, this, &clsWatchdog::onTimeout);
                          }
                          /**
                           * @brief clsWatchdog::kick - Keep watchdog from expiring
                           */
                          void clsWatchdog::kick() {
                              //Reset counter
                              muint16Counter = 0;
                          }
                          /**
                           * @brief clsWatchdog::onTimeout
                           */
                          void clsWatchdog::onTimeout() {
                              //Increment the counter
                              if ( ++muint16Counter >= muint16Setpoint ) {
                                  emit expired();
                              }
                          }
                          /**
                           * @brief clsWatchdog::pause - Use resume to restart
                           */
                          void clsWatchdog::pause() {
                              mtmrExpiry.stop();
                          }
                          /**
                           * @brief clsWatchdog::resume
                           */
                          void clsWatchdog::resume() {
                              mtmrExpiry.start();
                          }
                          

                          Kind Regards,
                          Sy

                          1 Reply Last reply
                          0
                          • SPlattenS Offline
                            SPlattenS Offline
                            SPlatten
                            wrote on last edited by
                            #19

                            So going back to my original purpose...having written and tested this class which works perfectly when running the application it resides in as a standalone module.

                            Now I'm launching this application from another Qt process, the process of launching this is:

                                QProcess::setProgram(crstrProgram);
                                //Register the module
                                clsModule::registerModule(this, crstrAlias);
                            
                                if ( blnStart != true ) {
                                    return;
                                }
                                //Start the process
                                start();
                                //Monitor when this process changes state
                                connect(this, &QProcess::stateChanged, this
                                            , [this](QProcess::ProcessState newState) {
                                    const qint64 cint64PID = processId();
                            
                                    if ( newState == QProcess::NotRunning ) {
                                //Only create the new instance if 'this' module already has a known PID
                                //and the PID valid and different from existing knownPID
                                        if ( mint64PID != 0 && cint64PID > 0 && cint64PID != mint64PID ) {
                                //Remove this instance of the module
                                            clsModule::newInstanceOf(*this);
                                        }
                                    } else if ( newState == QProcess::Running && cint64PID > 0 ) {
                                        const QString& crstrProgram(program());
                                        emit PID(crstrProgram, cint64PID);
                                    }
                                });
                            

                            crstrProgram is a passed in parameter defined as const QString&, it contains the name of the module / process to launch in this case mdFileIO.

                            I can see by looking at the running processes that both the launcher and mdFileIO are running, however when mdFileIO is started this way, the watchdog does not work and when I attach to the process the timer isn't running. Can anyone suggest why?

                            Kind Regards,
                            Sy

                            KroMignonK 1 Reply Last reply
                            0
                            • SPlattenS SPlatten

                              So going back to my original purpose...having written and tested this class which works perfectly when running the application it resides in as a standalone module.

                              Now I'm launching this application from another Qt process, the process of launching this is:

                                  QProcess::setProgram(crstrProgram);
                                  //Register the module
                                  clsModule::registerModule(this, crstrAlias);
                              
                                  if ( blnStart != true ) {
                                      return;
                                  }
                                  //Start the process
                                  start();
                                  //Monitor when this process changes state
                                  connect(this, &QProcess::stateChanged, this
                                              , [this](QProcess::ProcessState newState) {
                                      const qint64 cint64PID = processId();
                              
                                      if ( newState == QProcess::NotRunning ) {
                                  //Only create the new instance if 'this' module already has a known PID
                                  //and the PID valid and different from existing knownPID
                                          if ( mint64PID != 0 && cint64PID > 0 && cint64PID != mint64PID ) {
                                  //Remove this instance of the module
                                              clsModule::newInstanceOf(*this);
                                          }
                                      } else if ( newState == QProcess::Running && cint64PID > 0 ) {
                                          const QString& crstrProgram(program());
                                          emit PID(crstrProgram, cint64PID);
                                      }
                                  });
                              

                              crstrProgram is a passed in parameter defined as const QString&, it contains the name of the module / process to launch in this case mdFileIO.

                              I can see by looking at the running processes that both the launcher and mdFileIO are running, however when mdFileIO is started this way, the watchdog does not work and when I attach to the process the timer isn't running. Can anyone suggest why?

                              KroMignonK Offline
                              KroMignonK Offline
                              KroMignon
                              wrote on last edited by KroMignon
                              #20

                              @SPlatten said in Watchdog class:

                              Can anyone suggest why?

                              As I have written before: I suppose you try to start the timer from the wrong thread. QTimer start()/stop() must be called within the thread in which the timer is running.

                              It is an old maxim of mine that when you have excluded the impossible, whatever remains, however improbable, must be the truth. (Sherlock Holmes)

                              SPlattenS 1 Reply Last reply
                              1
                              • KroMignonK KroMignon

                                @SPlatten said in Watchdog class:

                                Can anyone suggest why?

                                As I have written before: I suppose you try to start the timer from the wrong thread. QTimer start()/stop() must be called within the thread in which the timer is running.

                                SPlattenS Offline
                                SPlattenS Offline
                                SPlatten
                                wrote on last edited by SPlatten
                                #21

                                @KroMignon, The instance of clsWatchdog is in the application class:

                                    class clsModHelper : public QObject {
                                    Q_OBJECT
                                
                                    protected:
                                        bool mblnStandalone;
                                        double mdblVersion;
                                        FILE* mfpDbgLog;
                                        qint64 mint64AppPID;
                                        clsWatchdog mobjWatchdog;
                                ...
                                

                                This class is the base class for the application:

                                    class clsModFileIO : public clsModHelper {
                                

                                The only instance of this class is created in:

                                int main(int intArgc, char* parystrArgv[]) {
                                    QCoreApplication a(intArgc, parystrArgv);
                                    clsModFileIO obj(intArgc, parystrArgv);
                                    return a.exec();
                                }
                                

                                The watchdog timer is started in its own default constructor which as its declared as a member of clsModHelper, must be in the main thread ?

                                Again, what I'm struggling to understand is why it works perfectly when the process is launched directly, but not from the other process using QProcess ?

                                Kind Regards,
                                Sy

                                KroMignonK 1 Reply Last reply
                                0
                                • SPlattenS SPlatten

                                  @KroMignon, The instance of clsWatchdog is in the application class:

                                      class clsModHelper : public QObject {
                                      Q_OBJECT
                                  
                                      protected:
                                          bool mblnStandalone;
                                          double mdblVersion;
                                          FILE* mfpDbgLog;
                                          qint64 mint64AppPID;
                                          clsWatchdog mobjWatchdog;
                                  ...
                                  

                                  This class is the base class for the application:

                                      class clsModFileIO : public clsModHelper {
                                  

                                  The only instance of this class is created in:

                                  int main(int intArgc, char* parystrArgv[]) {
                                      QCoreApplication a(intArgc, parystrArgv);
                                      clsModFileIO obj(intArgc, parystrArgv);
                                      return a.exec();
                                  }
                                  

                                  The watchdog timer is started in its own default constructor which as its declared as a member of clsModHelper, must be in the main thread ?

                                  Again, what I'm struggling to understand is why it works perfectly when the process is launched directly, but not from the other process using QProcess ?

                                  KroMignonK Offline
                                  KroMignonK Offline
                                  KroMignon
                                  wrote on last edited by
                                  #22

                                  @SPlatten It is very complicated to follow you.

                                  I don't really understand what is the purpose of your code, and which clsWatchdog instance you are talking about.

                                  What I believe to have understand:
                                  You have create software which starts other application with help of a custome QProcess class, why not.

                                  What I do not understand:

                                  • what is the purpose of the clsWatchdog ?
                                  • is clsWatchdog used by "launcher" application? Is this one which is not working as expected?
                                  • is clsWatchdog used by "external" application? Is this one which is not working as expected?

                                  It is an old maxim of mine that when you have excluded the impossible, whatever remains, however improbable, must be the truth. (Sherlock Holmes)

                                  SPlattenS 1 Reply Last reply
                                  0
                                  • KroMignonK KroMignon

                                    @SPlatten It is very complicated to follow you.

                                    I don't really understand what is the purpose of your code, and which clsWatchdog instance you are talking about.

                                    What I believe to have understand:
                                    You have create software which starts other application with help of a custome QProcess class, why not.

                                    What I do not understand:

                                    • what is the purpose of the clsWatchdog ?
                                    • is clsWatchdog used by "launcher" application? Is this one which is not working as expected?
                                    • is clsWatchdog used by "external" application? Is this one which is not working as expected?
                                    SPlattenS Offline
                                    SPlattenS Offline
                                    SPlatten
                                    wrote on last edited by
                                    #23

                                    @KroMignon , the launcher is the main engine, the processes it launchers are helper modules. The launcher will communicate with helpers to request services which the helpers will provide. Each helper will use the watchdog, it’s kept alive by the regular communication from the engine. If the engine is terminated then the communication stops and the purpose of the helpers ends so the watchdog will expire and each helper will terminate.

                                    Hope that helps?

                                    Kind Regards,
                                    Sy

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                                    • Christian EhrlicherC Offline
                                      Christian EhrlicherC Offline
                                      Christian Ehrlicher
                                      Lifetime Qt Champion
                                      wrote on last edited by Christian Ehrlicher
                                      #24

                                      @SPlatten said in Watchdog class:

                                      If the engine is terminated then the communication stops and the purpose of the helpers ends so the watchdog will expire and each helper will terminate.

                                      Use a QTimer instead some strange self-written classes.

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                                      • SPlattenS SPlatten

                                        @KroMignon , reading something is not proof that it does what it says! The reason I posted here in the first place is because having read the documentation, it doesn't seem to do what it is documented.

                                        I wish you would stop playing the same old record, its very tiresome and boring, just because once I said someplace that I didn't read the documentation does not make it my life story so get over it and move on.

                                        For the record I have been developing and writing software since 1987 professionally, so to say I don't read is insulting and wrong.

                                        W Offline
                                        W Offline
                                        wrosecrans
                                        wrote on last edited by
                                        #25

                                        @SPlatten said in Watchdog class:

                                        @KroMignon , reading something is not proof that it does what it says! The reason I posted here in the first place is because having read the documentation, it doesn't seem to do what it is documented.

                                        You seem really dedicated to having an XY problem for some reason: https://xyproblem.info/

                                        Why not just post about your original confusion with the documentation of QTimer? You say "it doesn't seem to do what it is documented" but you haven't actually explained what problem you were having with it. If there is a bug (in either the docs or the implementation), sharing the specifics will help get it fixed. If there isn't a bug in QTimer, sharing the specifics will help you get past the bug in your code using it.

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