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Deallocate memory to singleton class which access database ?

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  • KroMignonK KroMignon

    @Qt-embedded-developer said in Deallocate memory to singleton class which access database ?:

    Okay thanks. but still i am getting below errors:

    Do your compiler support C++11 and did you enable C++11 support (eg. add CONFIG += c++11 in your PRO file)?

    Q Offline
    Q Offline
    Qt embedded developer
    wrote on last edited by Qt embedded developer
    #14

    @KroMignon Hi i am not using qt . and sorry i can not enable C++ 11 because my compiler not support it. i can access map like std::map .

    KroMignonK 1 Reply Last reply
    0
    • Q Qt embedded developer

      @jsulm Okay thanks. but still i am getting below errors:

      "src\SqliteManagerBGSync.cpp", line 27: Error: #260-D: explicit type is missing ("int" assumed)
      for (const auto& kv : sqliteManagerMap) {
      ^
      "src\SqliteManagerBGSync.cpp", line 27: Error: #252: reference variable "kv" requires an initializer
      for (const auto& kv : sqliteManagerMap) {
      ^
      "src\SqliteManagerBGSync.cpp", line 27: Error: #65: expected a ";"
      for (const auto& kv : sqliteManagerMap) {
      ^
      "src\SqliteManagerBGSync.cpp", line 27: Error: #29: expected an expression
      for (const auto& kv : sqliteManagerMap) {
      ^
      "src\SqliteManagerBGSync.cpp", line 27: Error: #65: expected a ";"
      for (const auto& kv : sqliteManagerMap) {
      ^
      "src\SqliteManagerBGSync.cpp", line 28: Error: #153: expression must have class type
      delete kv.second;

      J.HilkJ Offline
      J.HilkJ Offline
      J.Hilk
      Moderators
      wrote on last edited by
      #15

      @Qt-embedded-developer

      SqliteManagerBGSync();
      cleanup();
      

      both are missing the return type, and also make sure to fix them in the *.cpp file as well!


      Be aware of the Qt Code of Conduct, when posting : https://forum.qt.io/topic/113070/qt-code-of-conduct


      Q: What's that?
      A: It's blue light.
      Q: What does it do?
      A: It turns blue.

      Q 1 Reply Last reply
      0
      • J.HilkJ J.Hilk

        @Qt-embedded-developer

        SqliteManagerBGSync();
        cleanup();
        

        both are missing the return type, and also make sure to fix them in the *.cpp file as well!

        Q Offline
        Q Offline
        Qt embedded developer
        wrote on last edited by
        #16

        @J-Hilk i have changed it . i have used void, But still i am getting as below mentioned error:

        "src\SqliteManagerBGSync.cpp", line 27: Error: #260-D: explicit type is missing ("int" assumed)
        for (const auto& kv : sqliteManagerMap) {
        ^
        "src\SqliteManagerBGSync.cpp", line 27: Error: #252: reference variable "kv" requires an initializer
        for (const auto& kv : sqliteManagerMap) {
        ^
        "src\SqliteManagerBGSync.cpp", line 27: Error: #65: expected a ";"
        for (const auto& kv : sqliteManagerMap) {
        ^
        "src\SqliteManagerBGSync.cpp", line 27: Error: #29: expected an expression
        for (const auto& kv : sqliteManagerMap) {
        ^
        "src\SqliteManagerBGSync.cpp", line 27: Error: #65: expected a ";"
        for (const auto& kv : sqliteManagerMap) {
        ^
        "src\SqliteManagerBGSync.cpp", line 28: Error: #153: expression must have class type
        delete kv.second;

        jsulmJ 1 Reply Last reply
        0
        • Q Qt embedded developer

          @J-Hilk i have changed it . i have used void, But still i am getting as below mentioned error:

          "src\SqliteManagerBGSync.cpp", line 27: Error: #260-D: explicit type is missing ("int" assumed)
          for (const auto& kv : sqliteManagerMap) {
          ^
          "src\SqliteManagerBGSync.cpp", line 27: Error: #252: reference variable "kv" requires an initializer
          for (const auto& kv : sqliteManagerMap) {
          ^
          "src\SqliteManagerBGSync.cpp", line 27: Error: #65: expected a ";"
          for (const auto& kv : sqliteManagerMap) {
          ^
          "src\SqliteManagerBGSync.cpp", line 27: Error: #29: expected an expression
          for (const auto& kv : sqliteManagerMap) {
          ^
          "src\SqliteManagerBGSync.cpp", line 27: Error: #65: expected a ";"
          for (const auto& kv : sqliteManagerMap) {
          ^
          "src\SqliteManagerBGSync.cpp", line 28: Error: #153: expression must have class type
          delete kv.second;

          jsulmJ Offline
          jsulmJ Offline
          jsulm
          Lifetime Qt Champion
          wrote on last edited by
          #17

          @Qt-embedded-developer As @KroMignon already asked you: do you have a C++11 capable compiler? And is C++11 activated?

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

          Q 1 Reply Last reply
          1
          • jsulmJ jsulm

            @Qt-embedded-developer As @KroMignon already asked you: do you have a C++11 capable compiler? And is C++11 activated?

            Q Offline
            Q Offline
            Qt embedded developer
            wrote on last edited by Qt embedded developer
            #18

            @jsulm no i have not. So what i have to change in below function:

            SqliteManagerBGSync::cleanup()
            {
            for (const auto& kv : sqliteManagerMap) {
                delete kv.second;
            }
            sqliteManagerMap.clear();
            
            }
            
            jsulmJ 1 Reply Last reply
            0
            • Q Qt embedded developer

              @KroMignon Hi i am not using qt . and sorry i can not enable C++ 11 because my compiler not support it. i can access map like std::map .

              KroMignonK Offline
              KroMignonK Offline
              KroMignon
              wrote on last edited by KroMignon
              #19

              @Qt-embedded-developer said in Deallocate memory to singleton class which access database ?:

              Hi i am not using qt . and sorry i can not enable C++ 11. i can access map like std::map .

              The problem is not std::map<>() but the way you iterate through the map: for (const auto& kv : sqliteManagerMap) requires at least C++11 support enabled! (cf. https://en.cppreference.com/w/cpp/container/map)

              I don't know which kind of C++ compiler you are using, for GCC for example enabling C++11 is done with -std=c++11 or -std=gnu++11

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

              Q 1 Reply Last reply
              3
              • Q Qt embedded developer

                @jsulm no i have not. So what i have to change in below function:

                SqliteManagerBGSync::cleanup()
                {
                for (const auto& kv : sqliteManagerMap) {
                    delete kv.second;
                }
                sqliteManagerMap.clear();
                
                }
                
                jsulmJ Offline
                jsulmJ Offline
                jsulm
                Lifetime Qt Champion
                wrote on last edited by
                #20

                @Qt-embedded-developer Then you can't use auto, write the type instead of auto

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

                1 Reply Last reply
                1
                • KroMignonK KroMignon

                  @Qt-embedded-developer said in Deallocate memory to singleton class which access database ?:

                  Hi i am not using qt . and sorry i can not enable C++ 11. i can access map like std::map .

                  The problem is not std::map<>() but the way you iterate through the map: for (const auto& kv : sqliteManagerMap) requires at least C++11 support enabled! (cf. https://en.cppreference.com/w/cpp/container/map)

                  I don't know which kind of C++ compiler you are using, for GCC for example enabling C++11 is done with -std=c++11 or -std=gnu++11

                  Q Offline
                  Q Offline
                  Qt embedded developer
                  wrote on last edited by
                  #21

                  @KroMignon i can not enable it like that because any change like that not allowed in my device.

                  J.HilkJ KroMignonK 2 Replies Last reply
                  0
                  • Q Qt embedded developer

                    @KroMignon i can not enable it like that because any change like that not allowed in my device.

                    J.HilkJ Offline
                    J.HilkJ Offline
                    J.Hilk
                    Moderators
                    wrote on last edited by
                    #22

                    @Qt-embedded-developer than do a normal for(x; x<y; ++x) loop


                    Be aware of the Qt Code of Conduct, when posting : https://forum.qt.io/topic/113070/qt-code-of-conduct


                    Q: What's that?
                    A: It's blue light.
                    Q: What does it do?
                    A: It turns blue.

                    Q 1 Reply Last reply
                    1
                    • J.HilkJ J.Hilk

                      @Qt-embedded-developer than do a normal for(x; x<y; ++x) loop

                      Q Offline
                      Q Offline
                      Qt embedded developer
                      wrote on last edited by
                      #23

                      @J-Hilk ,@jsulm ,@jsulm ,@KroMignon Thanks for enormous support.

                      i have written like it below and now its not show any error:

                      void SqliteManagerBGSync::cleanup()
                      {
                      for (short int i =0 ; i<sizeof(sqliteManagerMap);i++)
                      {
                          delete sqliteManagerMap[i];
                      }
                      sqliteManagerMap.clear();
                      
                      }
                      
                      J.HilkJ 1 Reply Last reply
                      0
                      • Q Qt embedded developer

                        @J-Hilk ,@jsulm ,@jsulm ,@KroMignon Thanks for enormous support.

                        i have written like it below and now its not show any error:

                        void SqliteManagerBGSync::cleanup()
                        {
                        for (short int i =0 ; i<sizeof(sqliteManagerMap);i++)
                        {
                            delete sqliteManagerMap[i];
                        }
                        sqliteManagerMap.clear();
                        
                        }
                        
                        J.HilkJ Offline
                        J.HilkJ Offline
                        J.Hilk
                        Moderators
                        wrote on last edited by
                        #24

                        @Qt-embedded-developer
                        using sizeof is almost certainly wrong here.

                        std::map has a size() function, please use that.
                        https://en.cppreference.com/w/cpp/container/map/size


                        Be aware of the Qt Code of Conduct, when posting : https://forum.qt.io/topic/113070/qt-code-of-conduct


                        Q: What's that?
                        A: It's blue light.
                        Q: What does it do?
                        A: It turns blue.

                        1 Reply Last reply
                        3
                        • Q Qt embedded developer

                          @KroMignon i can not enable it like that because any change like that not allowed in my device.

                          KroMignonK Offline
                          KroMignonK Offline
                          KroMignon
                          wrote on last edited by KroMignon
                          #25

                          @Qt-embedded-developer said in Deallocate memory to singleton class which access database ?:

                          i can not enable it like that because any change like that not allowed in my device.

                          As @jsulm already wrote before, replace auto with the corresponding type:

                          for(std::map<int,SqliteManagerBGSync*>::iterator it = sqliteManagerMap::begin(); it != sqliteManagerMap::end(); ++it)
                          {
                          ...
                          }
                          

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

                          J.HilkJ Q 3 Replies Last reply
                          1
                          • KroMignonK KroMignon

                            @Qt-embedded-developer said in Deallocate memory to singleton class which access database ?:

                            i can not enable it like that because any change like that not allowed in my device.

                            As @jsulm already wrote before, replace auto with the corresponding type:

                            for(std::map<int,SqliteManagerBGSync*>::iterator it = sqliteManagerMap::begin(); it != sqliteManagerMap::end(); ++it)
                            {
                            ...
                            }
                            
                            J.HilkJ Offline
                            J.HilkJ Offline
                            J.Hilk
                            Moderators
                            wrote on last edited by J.Hilk
                            #26

                            @KroMignon IIRC range based for loops is a c++11 feature in itself 🤔

                            never mind, I think need a break!


                            Be aware of the Qt Code of Conduct, when posting : https://forum.qt.io/topic/113070/qt-code-of-conduct


                            Q: What's that?
                            A: It's blue light.
                            Q: What does it do?
                            A: It turns blue.

                            KroMignonK 1 Reply Last reply
                            0
                            • J.HilkJ J.Hilk

                              @KroMignon IIRC range based for loops is a c++11 feature in itself 🤔

                              never mind, I think need a break!

                              KroMignonK Offline
                              KroMignonK Offline
                              KroMignon
                              wrote on last edited by
                              #27

                              @J-Hilk said in Deallocate memory to singleton class which access database ?:

                              IIRC range based for loops is a c++11 feature in itself 🤔

                              Are you sure? I don't believe that std::map<>::iterator support is comming with C++11.

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

                              jsulmJ 1 Reply Last reply
                              0
                              • KroMignonK KroMignon

                                @J-Hilk said in Deallocate memory to singleton class which access database ?:

                                IIRC range based for loops is a c++11 feature in itself 🤔

                                Are you sure? I don't believe that std::map<>::iterator support is comming with C++11.

                                jsulmJ Offline
                                jsulmJ Offline
                                jsulm
                                Lifetime Qt Champion
                                wrote on last edited by
                                #28

                                @KroMignon I think @J-Hilk misunderstood your code: you are not using range based loop

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

                                1 Reply Last reply
                                1
                                • KroMignonK KroMignon

                                  @Qt-embedded-developer said in Deallocate memory to singleton class which access database ?:

                                  i can not enable it like that because any change like that not allowed in my device.

                                  As @jsulm already wrote before, replace auto with the corresponding type:

                                  for(std::map<int,SqliteManagerBGSync*>::iterator it = sqliteManagerMap::begin(); it != sqliteManagerMap::end(); ++it)
                                  {
                                  ...
                                  }
                                  
                                  Q Offline
                                  Q Offline
                                  Qt embedded developer
                                  wrote on last edited by Qt embedded developer
                                  #29

                                  @KroMignon Here inside for loop i need to write

                                  for(std::map<int,SqliteManagerBGSync*>::iterator it = sqliteManagerMap::begin(); it != sqliteManagerMap::end(); ++it)
                                  {
                                  delete it;
                                  }
                                  
                                  

                                  or what i need to write to deallocate memory ?

                                  jsulmJ KroMignonK 2 Replies Last reply
                                  0
                                  • Q Qt embedded developer

                                    @KroMignon Here inside for loop i need to write

                                    for(std::map<int,SqliteManagerBGSync*>::iterator it = sqliteManagerMap::begin(); it != sqliteManagerMap::end(); ++it)
                                    {
                                    delete it;
                                    }
                                    
                                    

                                    or what i need to write to deallocate memory ?

                                    jsulmJ Offline
                                    jsulmJ Offline
                                    jsulm
                                    Lifetime Qt Champion
                                    wrote on last edited by
                                    #30

                                    @Qt-embedded-developer said in Deallocate memory to singleton class which access database ?:

                                    delete it;

                                    delete it->second;

                                    of course

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

                                    1 Reply Last reply
                                    1
                                    • Q Qt embedded developer

                                      @KroMignon Here inside for loop i need to write

                                      for(std::map<int,SqliteManagerBGSync*>::iterator it = sqliteManagerMap::begin(); it != sqliteManagerMap::end(); ++it)
                                      {
                                      delete it;
                                      }
                                      
                                      

                                      or what i need to write to deallocate memory ?

                                      KroMignonK Offline
                                      KroMignonK Offline
                                      KroMignon
                                      wrote on last edited by KroMignon
                                      #31

                                      @Qt-embedded-developer said in Deallocate memory to singleton class which access database ?:

                                      or what i need to write to deallocate ?

                                      Please, take time to read std::map<> documentation.
                                      You are using a map iterator, so it is a container object which gives you access to key and value.

                                      delete it do not make sense!

                                      You want to delete the pointer hold in the value part: delete it->second

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

                                      Q 1 Reply Last reply
                                      3
                                      • KroMignonK KroMignon

                                        @Qt-embedded-developer said in Deallocate memory to singleton class which access database ?:

                                        or what i need to write to deallocate ?

                                        Please, take time to read std::map<> documentation.
                                        You are using a map iterator, so it is a container object which gives you access to key and value.

                                        delete it do not make sense!

                                        You want to delete the pointer hold in the value part: delete it->second

                                        Q Offline
                                        Q Offline
                                        Qt embedded developer
                                        wrote on last edited by Qt embedded developer
                                        #32
                                        This post is deleted!
                                        1 Reply Last reply
                                        0
                                        • KroMignonK KroMignon

                                          @Qt-embedded-developer said in Deallocate memory to singleton class which access database ?:

                                          i can not enable it like that because any change like that not allowed in my device.

                                          As @jsulm already wrote before, replace auto with the corresponding type:

                                          for(std::map<int,SqliteManagerBGSync*>::iterator it = sqliteManagerMap::begin(); it != sqliteManagerMap::end(); ++it)
                                          {
                                          ...
                                          }
                                          
                                          Q Offline
                                          Q Offline
                                          Qt embedded developer
                                          wrote on last edited by
                                          #33

                                          @KroMignon Hi when i put sqliteManagerMap::begin() and sqliteManagerMap::end() i am getting error .

                                          like below :

                                          for(std::map<int,SqliteManagerBGSync *>::iterator it = sqliteManagerMap::begin(); it != sqliteManagerMap::end(); ++it)

                                          but when i put sqliteManagerMap.begin() then i am getting no error.

                                          jsulmJ KroMignonK 2 Replies Last reply
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