process heap is organized as chunk of free memory need not be contiguous and during freeing what free() does is update it's book keeping records and it's bins array so that next time if asked for new space may return the same space however it doesn't wipe the freed data but few run time directive are present in few rtdl libary to overwrite the freed space with some poison value ( configurable )
On Sun, Nov 13, 2011 at 11:52 PM, sumit mahamuni <[email protected]> wrote: > > > On Nov 11, 9:16 pm, saurabh singh <[email protected]> wrote: >> well that would be tough for the compiler to predict things that will >> happen during run time.Its the job of garbage collector to do that. > well compiler cant predict what will happen at runtime. >> >> >> >> >> >> >> >> >> >> On Fri, Nov 11, 2011 at 8:36 PM, shady <[email protected]> wrote: >> > ok, thanks. >> >> > why do we need to free the memory ? > if you do not free the memory, you will run out of the memory. > >> > Suppose i have a linked list of 1000 nodes and i make the head of it = >> > NULL, thus losing the whole list. Then compiler can look at other variables >> > and if this list has not been referenced anywhere else then it is useless, >> > thus will free the memory. >> > Is the argument wrong ? > >> >> > On Fri, Nov 11, 2011 at 8:20 PM, vikas <[email protected]>wrote: >> >> >> nopes , they are not connected, it is just a chance you are getting >> >> the same values and nothing is overwritten there: basically these are >> >> DANGLING POINTERS . Now you should keep practising something like this >> >> >> #define FREE(N) { free(N); N=NULL;} >> >> >> to avoid such mistakes >> >> >> On Nov 11, 3:41 pm, shady <[email protected]> wrote: >> >> > typedef struct n{ >> >> > int num; >> >> > struct n *next; >> >> >> > }node; >> >> >> > node is the structure to create the linked list. >> >> >> > node *list1; >> >> >> > I have created a linked list ( list1 )like this 1 -> 2 -> 3 -> 4 >> >> >> > so i free it like this ---- >> >> >> > free(list1 -> next -> next ->next); >> >> > free(list1 -> next -> next); >> >> > free(list1 -> next); >> >> > free(list1); >> >> >> > when i am printing the list after each free, it is always printing a >> >> > list of length 4, isn't the values free'd when we do free() ? >> >> >> > actual printing gives >> >> > 1 2 3 0 >> >> > 1 2 garbage 0 >> >> > 1 garbage garbage 0 >> >> > garbage garbage garbage 0 >> >> >> > why is the linked list still connected ? >> >> >> > actual print function ----- >> >> > void print(node *l) >> >> > { >> >> > while(l != NULL) >> >> > { >> >> > printf("%d\t",l->num); >> >> > l = l->next; >> >> > } >> >> > printf("\n"); >> >> >> > } >> >> >> -- >> >> You received this message because you are subscribed to the Google Groups >> >> "Algorithm Geeks" group. >> >> To post to this group, send email to [email protected]. >> >> To unsubscribe from this group, send email to >> >> [email protected]. >> >> For more options, visit this group at >> >>http://groups.google.com/group/algogeeks?hl=en. >> >> > -- >> > You received this message because you are subscribed to the Google Groups >> > "Algorithm Geeks" group. >> > To post to this group, send email to [email protected]. >> > To unsubscribe from this group, send email to >> > [email protected]. >> > For more options, visit this group at >> >http://groups.google.com/group/algogeeks?hl=en. >> >> -- >> Saurabh Singh >> B.Tech (Computer Science) >> MNNIT ALLAHABAD > > -- > You received this message because you are subscribed to the Google Groups > "Algorithm Geeks" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group at > http://groups.google.com/group/algogeeks?hl=en. > > -- You received this message because you are subscribed to the Google Groups "Algorithm Geeks" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/algogeeks?hl=en.
