9/6/2023 0 Comments Stack vs heap csmalloc has a return value of interest you should always check the return value. And by the way., kids don't try this at home.the malloc'ed buffer space is on the heap. The static keyword tells you that it's not to be allocated on the stack. is actually allocated exactly like at 2.The string, since it's a constant, is allocated in static data space along with the other strings. has the pointer allocated on the stack and will be effectively deallocated when main returns.is simply a static allocated pointer room for one address, in static data.The actual string is also being allocated as static data and put into a read-only segment in right-thinking machines. Instead, it's allocated as static data, and put into its own memory segment on most modern machines. This is neither allocated on the stack NOR on the heap.Let's assume you've got a tiny C(++ as well, they handle this the same way) program like this: /* my.c */Ĭhar * str = "Your dog has fleas." /* 1 */Ĭhar * str2 = "Don't make fun of my dog." /* 3 */ Accessing freed or deallocated memory is called undefined behavior.The problem here is the question. The above program can either: run properly, crash or give you a different result. its memory can be used for whatever pleases the program), you can no longer safely access it. Since after exiting the function the pointer is "destroyed" (i.e. The above code stores the address of a pointer residing on the stack (and leaks memory too because it doesn't free Object's allocated memory with delete). or even the same value as before, randomly - Undefined Behavior a different value after the pointer destruction The amount of memory that get’s assigned to an application depends on the computer’s architecture and will vary across most devices, but the variable that remains constant is the five parts of an application’s memory which are the heap, stack, initialized data segment, uninitialized data segment, and the text segment. } // pointerOnTheStack is NO LONGER valid after the function exits "data segment", could be heap or stackĬout << "*globalPtrToPtr = " << *globalPtrToPtr << endl Object** globalPtrToPtr // This is into another area called After that, the code might still work: #include The pointer is allocated on the stack and will last there for the entire duration of the function (or its scope). However, isn't it that the pointer to object m is on the same time Yes, the pointer is allocated on the stack but the object that pointer points to is allocated on the heap. the object m itself (so the data that it carries, as well as access to its methods) has been allocated on the heap a pointer to object m has been allocated on the stackĢ. I feel like for the sake of completeness, this should have been mentioned in this tutorial, leaving it out causes a bit of confusion to me, so I hope someone can clear this up and tell me that I am right with my understanding that this example should have basically two statements that would have to say:ġ. However, isn't it that the pointer to object m is on the same time allocated on the stack? Otherwise, how would the object itself, which of course is sitting in the heap be accessed. According to my understanding, the object itself indeed is allocated on the heap as the new keyword has been used for its instantiation. It is explained that the object m is allocated on the heap, I am just wondering if this is the full story. In the second explanation however, I came across an example to which I have a specific question, the example is this: I am trying to understand the difference between the stack and heap memory, and this question on SO as well as this explanation did a pretty good job explaining the basics.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |