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Access Violation Delete Pointer

Good jobHamza MerzićGreat article! You don't ever test to see if the pointer is out of the range of the number of bytes that you allocated. In addition to mistake #10, it might be worth to mention that this is not thread-safe. I can't think of how to do that it's so abnormal! this content

getChild() can be implemented as `return std::shared_ptr(shared_from_this(), m_child.data())`. If you are, you should be using an object pool. bool shouldBeRemoved (GameObject* val) { return (val->time >= 2); } std::remove_if(gameObjectList.begin(), gameObjectList.end(), shouldBeRemoved); share|improve this answer edited Oct 16 '12 at 15:18 famousgarkin 687722 answered Oct 7 '12 at 11:15 ManicQin C++ Information Tutorials Reference Articles Forum Forum BeginnersWindows ProgrammingUNIX/Linux ProgrammingGeneral C++ ProgrammingLoungeJobs Home page | Privacy policy© cplusplus.com, 2000-2016 - All rights reserved - v3.1Spotted an error?

What is this metal rail in the basement ceiling more hot questions question feed lang-cpp about us tour help blog chat data legal privacy policy work here advertising info mobile contact more hot questions question feed lang-cpp about us tour help blog chat data legal privacy policy work here advertising info mobile contact us feedback Technology Life / Arts Culture / Recreation Pointers aren't NULL by default.In general you need to initialize all your variables (they aren't defaulted on their own in release mode), otherwise they can create hard to track down bugs In my opinion, it made teaching C++ to newcomers much easier.

  1. hcg2007 The fix for #10 is wrong.
  2. However, this is risky and should be avoided.
  3. Create a new helper list and add the live objects to that new helper list, when the loop is over, remove the old list from memory and have it's pointer point
  4. And when slicing is allowed.Vatroslav BodrozicThank you :) You are right regarding unique_ptr, it is not clear from the text.
  5. Your problem is almost certainly in there. –Ed S.
  6. If it must be a pointer maybe you could use a Boost Smart Pointer instead: #include #define MAX_PACKET_SIZE 0x3FFF DWORD MyClass::GetFile( LPCSTR lpszRemoteFile, LPCSTR lpszLocalFile ) { boost::scoped_array bufferPtr; ...
  7. Please click the link in the confirmation email to activate your subscription.
  8. Mat, what should I use? –Bonnev May 3 '14 at 11:36 1 "what should I use" - to do what?
  9. Let us consider the following code: Thread 1: Connection& connection= connections.GetConnection(connectionId); // ...
  10. Recommendation: Use make_shared to instantiate shared pointers instead of using the raw pointer.

lpBuffer = new BYTE[MAX_PACKET_SIZE]; // ... Practically, when I profiled both solutions in a loop 1M times, I found no difference in performance. Are people of Nordic Nations "happier, healthier" with "a higher standard of living overall than Americans"? It is both safe and performant if you store your actual objects in a container (preferably a vector) and implement the relationships between them using raw pointers.

So inside the function it will also call a method from the class “A” instead of a method from the class “B” which is most likely not what is expected by Reply to quoted postsClear » Forums » Home » Forums » The Technical Side » For Beginners Change Theme IP.Board GDNet 3.4.1 GDNet 6.0 English (USA) English (USA) English (USA) Back to top #5 Fl00Fy Members 198 Like 0Likes Like Posted 16 March 2013 - 09:01 AM Ah I see. I think the recommendation should be that if you think about using an array, just use a vector.

share|improve this answer answered Dec 1 '11 at 20:55 Mark Ransom 185k24206412 add a comment| up vote 1 down vote I'm not really sure why an access violation is caused here Two possibilities come to mind: The error is not actually in the delete but in the code just on either side. And one common sense, the dest method is called on this object, so how this can be null (it is possible to call destructor on null object, but then it is delete already calls the destructor automatically.

Common Mistake #4: Returning a Local Object by Reference This is mostly a beginner’s mistake, but it is worth mentioning since there is a lot of legacy code that suffers from However, this was just the simplest example of this C++ problem. I don't see why it "should also" be done –M.M May 3 '14 at 12:48 add a comment| Your Answer draft saved draft discarded Sign up or log in Sign Of course, after a quick glance, you should check that the file length is exactly the same (dir for Windows, ls -l for Linux) as the original and use "fc" for

Back to top #7 Fl00Fy Members 198 Like 0Likes Like Posted 16 March 2013 - 09:51 AM Alright. http://arnoldtechweb.com/access-violation/access-violation-in-c.html I apologize for the confusion. Join them; it only takes a minute: Sign up I'm getting read access violation while deleting pointer [closed] up vote -3 down vote favorite C03View::~C03View() { delete pBrush_;//this causes read access void myFunction(std::shared_ptr a, std::shared_ptr b); // now call that function from somewhere: myFunction(new MyClass(), new MyClass()); This call is just a short way (by implicit conversion) of writting: myFunction(std::shared_ptr (new MyClass()),

Back to top #6 cardinal Members 908 Like 2Likes Like Posted 16 March 2013 - 09:39 AM You should also initialize the pointer to NULL. void GameObjectFactory::Update() { for( std::list::iterator it=gameObjectList.begin() ..... (*it)->Update(); } void Bomb::Update() { if( time == 2.0f ) { gameObjectFactory->Remove( this ); } } void GameObjectFactory::Remove( ... ) { gameObjectList.remove( ... ); No new replies allowed. have a peek at these guys It should receive a reference to the object it cares about (or a pointer).

I suggested some changes to the article, so it can be even more clear that using of auto_ptr is a bad thing to do if other options are available.Vatroslav BodrozicThank you Mistake #2 : Not making resources/objects shared by shared_ptr threadsafe ! how can I do that?

Let’s say somebody created a library that has a string class: class String { public: String(int n); String(const char *s); …. } The first method is intended to create a string

If it is to be deleted then you should call reset(). So I think raw pointers (and references to their objects) have an important role to play in a universe where all resources are owned using smart pointers (or containers). How can "USB stick" online identification possibly work? If you know what type of object you want, and polymorphic behaviour is not needed, then a local solid object is often the way to go. (see e.g.

Archeological evidence of nuclear warfare Dealing cards, derangements, and probability: Is the Riddler Express solution incorrect? Using smart pointers, such as auto_ptr, unique_ptr, shared_ptr, with arrays is also incorrect. You could store a seperate std::vector or std::list of objects to be deleted which some sort of object manager could process. –derivative Oct 6 '12 at 16:46 I'm storing check my blog I plan to write a new article about exception safety in C++ and your suggestion will fit perfectly inside it :)Vatroslav BodrozicThank you :) Next time I will write about exception

So Safety is no longer a concern for this type of usage. MFC is even written to handle that case (some, not all classes). –Stephen Kellett May 29 '14 at 23:58 add a comment| up vote 4 down vote Below code should be But there still is no dependency cycle. share|improve this answer answered Dec 1 '11 at 20:50 Joel 1,67321228 add a comment| Your Answer draft saved draft discarded Sign up or log in Sign up using Google Sign

The transfer of ownership executed by the copy constructor when the pointer is passed by value can cause fatal crashes in the system when the original auto pointer gets dereferenced again. It is restrictive because it means that only one type of smart pointer can be passed to a function but the function should not have to care what type of smart I would try it with short files, but I would be sure to use files that have lengths that are all possible values modulo 8 (since you are reading 8 bytes I was adding 8 64-bit value addresses to the pointer instead of adding 1 address at a time.

Equation system with two unknown variables Anagram puzzle whose solution is guaranteed to make you laugh Is there any term for this when movie doesn't end as its plot suggests Does It requires a little bit more typing, but it is much cleaner to read and can help avoid unpredictable results. If you need more code than this let me know. Francisco Miguel García In a multithread app, #10 could generate a race-condition.

Some designs don't require you to do this ceck: Suppose you have a Node class that itself creates a child. Thank you. –Balls Oct 6 '12 at 16:48 Is it possible you are changing the list while you are still iterating over the list? –zehelvion Oct 6 '12 at Safe way to get a few more inches under car on flat surface What are the benefits of an oral exam? There is only one place in my code where I initialize this object: void C03View::OnInitialUpdate() { CScrollView::OnInitialUpdate(); pRenderTarget_ = GetRenderTarget(); pBrush_ = new CD2DSolidColorBrush(GetRenderTarget(), D2D1::ColorF(D2D1::ColorF::Blue)); } This project is a MFC

It is also incorrect to use the delete operator without [] brackets for primitive types, even though there is no destructor for these types.