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memory leak in the code?

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performancequestion
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  • G George_George

    Thanks CPallini! I think you mean we have to delete A, right? regards, George

    CPalliniC Offline
    CPalliniC Offline
    CPallini
    wrote on last edited by
    #4

    Yes. :)

    If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.
    [my articles]

    In testa che avete, signor di Ceprano?

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    • G George_George

      Hello everyone, Should I delete memory pointed by pointer a if there is bad_alloc when allocating memory in memory pointed by pointer b? I am not sure whether there will be memory leak if I do not delete a.try { a = new int [N]; b = new int [M]; } catch (bad_alloc) { // if a success, but b fail, should we try to delete[] a here to avoid memory leak? }
      thanks in advance, George

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      Eytukan
      wrote on last edited by
      #5

      Hello George, nice to see you again. But this time I've got a question for you. Straight to you. Why do are you acting 'quick'-judgemental before someone could actually reply you fully?:~ See here[^] And I've seen many times , anybody who replies to your thread gets a 3 vote. Immediately. Is it a token of acknowledgment to say that you've read the message? :-). I'm really not hurt by that but I'm finding it funny! Why do you do that?


      OK,. what country just started work for the day ? The ASP.NET forum is flooded with retarded questions. -Christian Graus Best wishes to Rexx[^]

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      • G George_George

        Hello everyone, Should I delete memory pointed by pointer a if there is bad_alloc when allocating memory in memory pointed by pointer b? I am not sure whether there will be memory leak if I do not delete a.try { a = new int [N]; b = new int [M]; } catch (bad_alloc) { // if a success, but b fail, should we try to delete[] a here to avoid memory leak? }
        thanks in advance, George

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        pierre_ribery
        wrote on last edited by
        #6

        In a case like this you should initialize both a and b to 0 before the try clause. You cannot delete a or b at this stage, I assume you will need to use them later, or what was the purpose of allocating them? int* a = NULL; int* b = NULL; try { a = new int [N]; b = new int [M]; } catch (bad_alloc) { // Tell the user if a or b failed... } // Do some stuff on a or b // Now delete if they are allocated if(a) delete a[]; if (b) delete b[]; Thanks!

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        • G George_George

          Hello everyone, Should I delete memory pointed by pointer a if there is bad_alloc when allocating memory in memory pointed by pointer b? I am not sure whether there will be memory leak if I do not delete a.try { a = new int [N]; b = new int [M]; } catch (bad_alloc) { // if a success, but b fail, should we try to delete[] a here to avoid memory leak? }
          thanks in advance, George

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          Hamid Taebi
          wrote on last edited by
          #7

          Why you didnt use like this code try { int * a= new int[N]; int * b= new int[M]; } catch (bad_alloc&) { cout <<"Error allocating memory!"; }

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          • H Hamid Taebi

            Why you didnt use like this code try { int * a= new int[N]; int * b= new int[M]; } catch (bad_alloc&) { cout <<"Error allocating memory!"; }

            E Offline
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            Eytukan
            wrote on last edited by
            #8

            huh Hamid! :| it's simply because he should have put it like:

            int* a;
            int* b;

            try { a= new int[N]; b= new int[M]; } catch (bad_alloc&) { cout <<"Error allocating memory!"; } wake up! :)


            OK,. what country just started work for the day ? The ASP.NET forum is flooded with retarded questions. -Christian Graus Best wishes to Rexx[^]

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            • CPalliniC CPallini

              You have always to do your cleanup stuff! :)

              If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.
              [my articles]

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              Eytukan
              wrote on last edited by
              #9

              But I suggest he should do something like this : if(pMyStuff!=NULL) { delete pMyStuff; } :cool:


              OK,. what country just started work for the day ? The ASP.NET forum is flooded with retarded questions. -Christian Graus Best wishes to Rexx[^]

              CPalliniC 1 Reply Last reply
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              • E Eytukan

                huh Hamid! :| it's simply because he should have put it like:

                int* a;
                int* b;

                try { a= new int[N]; b= new int[M]; } catch (bad_alloc&) { cout <<"Error allocating memory!"; } wake up! :)


                OK,. what country just started work for the day ? The ASP.NET forum is flooded with retarded questions. -Christian Graus Best wishes to Rexx[^]

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                Hamid Taebi
                wrote on last edited by
                #10

                Yeah it was a quick sample. ;)

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                • E Eytukan

                  huh Hamid! :| it's simply because he should have put it like:

                  int* a;
                  int* b;

                  try { a= new int[N]; b= new int[M]; } catch (bad_alloc&) { cout <<"Error allocating memory!"; } wake up! :)


                  OK,. what country just started work for the day ? The ASP.NET forum is flooded with retarded questions. -Christian Graus Best wishes to Rexx[^]

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                  pierre_ribery
                  wrote on last edited by
                  #11

                  Not like that, see my earlier post. Always initialize pointers!! In this case set them to NULL(0). int* a = NULL; int* b = NULL;

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                  • P pierre_ribery

                    Not like that, see my earlier post. Always initialize pointers!! In this case set them to NULL(0). int* a = NULL; int* b = NULL;

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                    E Offline
                    Eytukan
                    wrote on last edited by
                    #12

                    Who said I didn't do it? I'm a c++ programmer. class myclass { int* a; int* b; myclass() { a= NULL; b= NULL; } } ;P


                    OK,. what country just started work for the day ? The ASP.NET forum is flooded with retarded questions. -Christian Graus Best wishes to Rexx[^]

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                    • E Eytukan

                      But I suggest he should do something like this : if(pMyStuff!=NULL) { delete pMyStuff; } :cool:


                      OK,. what country just started work for the day ? The ASP.NET forum is flooded with retarded questions. -Christian Graus Best wishes to Rexx[^]

                      CPalliniC Offline
                      CPalliniC Offline
                      CPallini
                      wrote on last edited by
                      #13

                      And you are right! :-D

                      If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.
                      [my articles]

                      In testa che avete, signor di Ceprano?

                      1 Reply Last reply
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                      • E Eytukan

                        Who said I didn't do it? I'm a c++ programmer. class myclass { int* a; int* b; myclass() { a= NULL; b= NULL; } } ;P


                        OK,. what country just started work for the day ? The ASP.NET forum is flooded with retarded questions. -Christian Graus Best wishes to Rexx[^]

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                        pierre_ribery
                        wrote on last edited by
                        #14

                        Your code said it. Anyway, I think it is pretty important to show it in the code as well.

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                        • P pierre_ribery

                          In a case like this you should initialize both a and b to 0 before the try clause. You cannot delete a or b at this stage, I assume you will need to use them later, or what was the purpose of allocating them? int* a = NULL; int* b = NULL; try { a = new int [N]; b = new int [M]; } catch (bad_alloc) { // Tell the user if a or b failed... } // Do some stuff on a or b // Now delete if they are allocated if(a) delete a[]; if (b) delete b[]; Thanks!

                          G Offline
                          G Offline
                          George_George
                          wrote on last edited by
                          #15

                          Thanks pierre_ribery, I want to confirm with you that your point is we need to delete a or b if they are successful allocated, even if bad_alloc happens (may be caused by other statements), right? regards, George

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                          • H Hamid Taebi

                            Why you didnt use like this code try { int * a= new int[N]; int * b= new int[M]; } catch (bad_alloc&) { cout <<"Error allocating memory!"; }

                            G Offline
                            G Offline
                            George_George
                            wrote on last edited by
                            #16

                            Hi Hamid, I am confused. My question is about whether we need to delete a or b if bad_alloc happens, does your reply has anything related to my question? :-) regards, George

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                            • CPalliniC CPallini

                              Yes. :)

                              If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.
                              [my articles]

                              G Offline
                              G Offline
                              George_George
                              wrote on last edited by
                              #17

                              Thanks for your confirmation, CPallini! regards, George

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                              • G George_George

                                Hi Hamid, I am confused. My question is about whether we need to delete a or b if bad_alloc happens, does your reply has anything related to my question? :-) regards, George

                                H Offline
                                H Offline
                                Hamid Taebi
                                wrote on last edited by
                                #18

                                My reply was for check does it with success or no (and my suggestion is when you want to allocate or convert use of try/catch block) and when you got error means that it doesnt allocate any thing to variable.

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                                • G George_George

                                  Thanks pierre_ribery, I want to confirm with you that your point is we need to delete a or b if they are successful allocated, even if bad_alloc happens (may be caused by other statements), right? regards, George

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                                  pierre_ribery
                                  wrote on last edited by
                                  #19

                                  Yes that was exactly my point! If you have allocated memory, then you have to delete it. Therefore it is vital to initialize your pointers to 0 before using them. Cheers, Pierre

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                                  • H Hamid Taebi

                                    My reply was for check does it with success or no (and my suggestion is when you want to allocate or convert use of try/catch block) and when you got error means that it doesnt allocate any thing to variable.

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                                    George_George
                                    wrote on last edited by
                                    #20

                                    Thanks Hamid, I have developed a couple of samples, which specific case do you think I need to check? regards, George

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                                    • P pierre_ribery

                                      Yes that was exactly my point! If you have allocated memory, then you have to delete it. Therefore it is vital to initialize your pointers to 0 before using them. Cheers, Pierre

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                                      George_George
                                      wrote on last edited by
                                      #21

                                      Thanks for your advice, Pierre! regards, George

                                      1 Reply Last reply
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                                      • G George_George

                                        Thanks Hamid, I have developed a couple of samples, which specific case do you think I need to check? regards, George

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                                        H Offline
                                        Hamid Taebi
                                        wrote on last edited by
                                        #22

                                        If you check each block of your program(for exmaple is hwnd valid,etc) you can almost(not always) sure that you didnt get an exception when you run your program

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                                        • H Hamid Taebi

                                          If you check each block of your program(for exmaple is hwnd valid,etc) you can almost(not always) sure that you didnt get an exception when you run your program

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                                          G Offline
                                          George_George
                                          wrote on last edited by
                                          #23

                                          Hi Hamid, How could I check manually which block is exception safe or not? There are too many runtime errors, like out of memory or input invalid values to new which will cause bad_alloc. :-) regards, George

                                          H 1 Reply Last reply
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