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dlete pointer.

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  • S see me

    When ever i try to delete a pointer exception is occuring. if any reson for this?????:confused: yours faithfully ajeeshcv

    T Offline
    T Offline
    toxcct
    wrote on last edited by
    #2

    how do you do it ? isn't the pointer already deleted (it's a possibility) ?


    TOXCCT >>> GEII power

    [VisualCalc 3.0  updated ][Flags Beginner's Guide  new! ]

    S 1 Reply Last reply
    0
    • T toxcct

      how do you do it ? isn't the pointer already deleted (it's a possibility) ?


      TOXCCT >>> GEII power

      [VisualCalc 3.0  updated ][Flags Beginner's Guide  new! ]

      S Offline
      S Offline
      see me
      wrote on last edited by
      #3

      no...i tried to delete it after checking.:(( if( pPointer ) { delete pPointer; pPointer = 0; } yours faithfully ajeeshcv

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      • S see me

        When ever i try to delete a pointer exception is occuring. if any reson for this?????:confused: yours faithfully ajeeshcv

        V Offline
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        Viorel
        wrote on last edited by
        #4

        Possible causes:

        • un-initialized pointer, like int * p; delete p;
        • pointer does not point to an object created with new: int x; int * p = &x; delete p;
        • multiple execution of delete: int * p = new int; delete p; delete p;
        • pointed zone was altered by other code: int * p = new int; memset(p-100, 0, 1000); delete p;
          Note that null value of pointer does not generate exception. This is OK: int * p = NULL; delete p; -- modified at 3:58 Wednesday 14th June, 2006
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        • S see me

          When ever i try to delete a pointer exception is occuring. if any reson for this?????:confused: yours faithfully ajeeshcv

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          John R Shaw
          wrote on last edited by
          #5

          You need to be more specific, what do you mean by delete a pointer? I assume memory pointer, but these days it is hard to say. What compiler of language are you using? INTP "Program testing can be used to show the presence of bugs, but never to show their absence."Edsger Dijkstra

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          • S see me

            no...i tried to delete it after checking.:(( if( pPointer ) { delete pPointer; pPointer = 0; } yours faithfully ajeeshcv

            T Offline
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            toxcct
            wrote on last edited by
            #6

            and what is the error ?????


            TOXCCT >>> GEII power

            [VisualCalc 3.0  updated ][Flags Beginner's Guide  new! ]

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            • S see me

              no...i tried to delete it after checking.:(( if( pPointer ) { delete pPointer; pPointer = 0; } yours faithfully ajeeshcv

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              Cedric Moonen
              wrote on last edited by
              #7

              What is the exact error ? Maybe your pointer points to an invalid address. You probably left it uninitialized and then try to delete it.


              Cédric Moonen Software developer
              Charting control

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              • V Viorel

                Possible causes:

                • un-initialized pointer, like int * p; delete p;
                • pointer does not point to an object created with new: int x; int * p = &x; delete p;
                • multiple execution of delete: int * p = new int; delete p; delete p;
                • pointed zone was altered by other code: int * p = new int; memset(p-100, 0, 1000); delete p;
                  Note that null value of pointer does not generate exception. This is OK: int * p = NULL; delete p; -- modified at 3:58 Wednesday 14th June, 2006
                S Offline
                S Offline
                see me
                wrote on last edited by
                #8

                In my case the above mentioned 4 cases will not be satisfied. Actual reason is any other.:-> And also as per ur comments int * p = NULL; delete p; how the datas will be deleted from the location which is pointed by p initialy. since u r saying to delete the pointer after asigning the pointer to null.:confused: yours faithfully ajeeshcv

                T C V 3 Replies Last reply
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                • T toxcct

                  and what is the error ?????


                  TOXCCT >>> GEII power

                  [VisualCalc 3.0  updated ][Flags Beginner's Guide  new! ]

                  S Offline
                  S Offline
                  see me
                  wrote on last edited by
                  #9

                  exception is occuring. yours faithfully ajeeshcv

                  C T 2 Replies Last reply
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                  • S see me

                    exception is occuring. yours faithfully ajeeshcv

                    T Offline
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                    toxcct
                    wrote on last edited by
                    #10

                    Ajeesh c v wrote:

                    exception is occuring.

                    DAMNNNNN !!! WHICHHHH ????? if you don't provide some descriptions of your error case, how can one help you ?? :~ :mad:


                    TOXCCT >>> GEII power

                    [VisualCalc 3.0  updated ][Flags Beginner's Guide  new! ]

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                    • S see me

                      When ever i try to delete a pointer exception is occuring. if any reson for this?????:confused: yours faithfully ajeeshcv

                      H Offline
                      H Offline
                      Hamid Taebi
                      wrote on last edited by
                      #11

                      Can you show how to use pointer and how to declare pointer_**


                      **_

                      whitesky


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                      • S see me

                        exception is occuring. yours faithfully ajeeshcv

                        C Offline
                        C Offline
                        Cedric Moonen
                        wrote on last edited by
                        #12

                        That's a very clear description of the problem :~ The solution is: you did something wrong.


                        Cédric Moonen Software developer
                        Charting control

                        S 1 Reply Last reply
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                        • S see me

                          In my case the above mentioned 4 cases will not be satisfied. Actual reason is any other.:-> And also as per ur comments int * p = NULL; delete p; how the datas will be deleted from the location which is pointed by p initialy. since u r saying to delete the pointer after asigning the pointer to null.:confused: yours faithfully ajeeshcv

                          T Offline
                          T Offline
                          toxcct
                          wrote on last edited by
                          #13

                          Ajeesh c v wrote:

                          int * p = NULL; delete p; how the datas will be deleted from the location which is pointed by p initialy. since u r saying to delete the pointer after asigning the pointer to null.

                          he doesn't say it is the things to do... the cases enumerated are possible causes for a crash when deleting a pointer X|


                          TOXCCT >>> GEII power

                          [VisualCalc 3.0  updated ][Flags Beginner's Guide  new! ]

                          1 Reply Last reply
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                          • S see me

                            In my case the above mentioned 4 cases will not be satisfied. Actual reason is any other.:-> And also as per ur comments int * p = NULL; delete p; how the datas will be deleted from the location which is pointed by p initialy. since u r saying to delete the pointer after asigning the pointer to null.:confused: yours faithfully ajeeshcv

                            C Offline
                            C Offline
                            Cedric Moonen
                            wrote on last edited by
                            #14

                            Ajeesh c v wrote:

                            how the datas will be deleted from the location which is pointed by p initialy. since u r saying to delete the pointer after asigning the pointer to null.

                            That's probably your problem. When you do this:

                            int* pTest;
                            if (pTest)
                            delete pTest;

                            You will have an excpetion because you try to delete memory that is unitianalized (you can only delete memory that has been allocated with new). So, to be sure not to delete this 'unexistant' memory, assign NULL to the pointer. This is safe.


                            Cédric Moonen Software developer
                            Charting control

                            1 Reply Last reply
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                            • S see me

                              In my case the above mentioned 4 cases will not be satisfied. Actual reason is any other.:-> And also as per ur comments int * p = NULL; delete p; how the datas will be deleted from the location which is pointed by p initialy. since u r saying to delete the pointer after asigning the pointer to null.:confused: yours faithfully ajeeshcv

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                              V Offline
                              Viorel
                              wrote on last edited by
                              #15

                              According to documentation (http://msdn2.microsoft.com/en-us/library/h6227113.aspx[^]), “You can [...] use delete on a pointer with the value 0”. Therefore instead of

                              if( p != NULL )
                              {
                                  delete p;
                                  p = NULL;
                              }
                              

                              you can use

                              delete p;
                              p = NULL;
                              

                              However, this does not belong to original topic. I think you should put a breakpoint at the line where your block of memory is allocated and the pointer is assigned. Then investigate the pointer’s value and the content of the memory block. Then stop on the line where the pointer is deleted. Check if the pointer contains right address value. Try to use step-be-step execution during deletion. Perhaps the pointer points to an object having destructor, and the problem is within this function.

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                              • T toxcct

                                Ajeesh c v wrote:

                                exception is occuring.

                                DAMNNNNN !!! WHICHHHH ????? if you don't provide some descriptions of your error case, how can one help you ?? :~ :mad:


                                TOXCCT >>> GEII power

                                [VisualCalc 3.0  updated ][Flags Beginner's Guide  new! ]

                                S Offline
                                S Offline
                                see me
                                wrote on last edited by
                                #16

                                ok... I think the problem is occuring due to this reason. am initializing the pointer from thread...adn try to delete it from another thread.. if there is any chance of occuring exception???? Please help me... yours faithfully ajeeshcv

                                T V J 3 Replies Last reply
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                                • S see me

                                  ok... I think the problem is occuring due to this reason. am initializing the pointer from thread...adn try to delete it from another thread.. if there is any chance of occuring exception???? Please help me... yours faithfully ajeeshcv

                                  T Offline
                                  T Offline
                                  toxcct
                                  wrote on last edited by
                                  #17

                                  as far as you don't answer my questions, i don't help you furthermore. :zzz:


                                  TOXCCT >>> GEII power

                                  [VisualCalc 3.0  updated ][Flags Beginner's Guide  new! ]

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                                  • C Cedric Moonen

                                    That's a very clear description of the problem :~ The solution is: you did something wrong.


                                    Cédric Moonen Software developer
                                    Charting control

                                    S Offline
                                    S Offline
                                    see me
                                    wrote on last edited by
                                    #18

                                    Thats a very precious information for me. Thank you.. yours faithfully ajeeshcv

                                    1 Reply Last reply
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                                    • S see me

                                      ok... I think the problem is occuring due to this reason. am initializing the pointer from thread...adn try to delete it from another thread.. if there is any chance of occuring exception???? Please help me... yours faithfully ajeeshcv

                                      V Offline
                                      V Offline
                                      Viorel
                                      wrote on last edited by
                                      #19

                                      I think this causes problems if your project’s configuration does not allow multi-threading. You should open the project’s properties dialog and be sure that the C/C++ --> Code Generation --> Runtime Library option contains a right value related to multi-threading. Then rebuild the application.

                                      S 1 Reply Last reply
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                                      • H Hamid Taebi

                                        Can you show how to use pointer and how to declare pointer_**


                                        **_

                                        whitesky


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                                        see me
                                        wrote on last edited by
                                        #20

                                        The pointer is of a dialog. Initialization: CMyDialog* pMyDialog; pMyDialog = new CMyDialog; pMyDialog->EndDialog(0); if(pMyDialog) { delete pMyDialog; pMyDialog = 0; } yours faithfully ajeeshcv

                                        H 1 Reply Last reply
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                                        • V Viorel

                                          I think this causes problems if your project’s configuration does not allow multi-threading. You should open the project’s properties dialog and be sure that the C/C++ --> Code Generation --> Runtime Library option contains a right value related to multi-threading. Then rebuild the application.

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                                          see me
                                          wrote on last edited by
                                          #21

                                          Thank you... I don't know it will work or not. Let me check. yours faithfully ajeeshcv

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