Std map erase free memory

images std map erase free memory

While in the currect Standard it's 'void', check your implementation for it as a possible extension. Sign up using Email and Password. If you're newing a lot of similar objects then you need to keep them somewhere. Visit chat. This way, if code that accesses the global variable is compilable, it means that it will behave as expected at run-time. This might get a bit out of the scope of this thread, but let's do it anyways: A. No, the objects referred to by the pointers in your map will not be deleted. Is there any function that allows me to completely remove and deallocate all contents of a std::map? Nick Keighley.

  • Doese erase() free the memory C++ Forum
  • the correct way to delete a map C / C++
  • c++ map erase() Stack Overflow
  • map erase() function in C++ STL GeeksforGeeks

  • No it doesn't free the memory if it is a naked pointer. When you erase from a map, it only removes the element. This article deals with the deletion part of Maps. Using erase(): erase() is used to erase the pair in map mentioned in argument, either its position, its value or a. map::erase() is a built-in function in C++ STL which is used to erase element from the container. It can be used to erase keys, elements at any specified position.
    If a variable is global it should be valid at all times, not just during a local scope even if that local scope is the main function.

    This can tremendously increase the effectiveness of the programming.

    Doese erase() free the memory C++ Forum

    The instantiator generates many objects of various classes derived from Type. This piece of code basically creates a global alias for a local variable. However, I don't agree that "the code will fail in an obvious way under testing" is a good thing. Real answer: Use valgrind. You could add some bureaucracy around the variable but it won't give you any substantial benefit.

    images std map erase free memory
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    Roland Pibinger.

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    the correct way to delete a map C / C++

    This may be unacceptable for a real parser. The bad thing is that you need to use additional libraries, such as boost. It hasn't led to safety or maintainability problems.

    now 'it' point to the element created by new as above (it); // Destructor of A is called, what about the memory allocated?

    delete ap. It doesn't free any memory as far as I know, is what I meant to say. typedef std::mapstd::string, const T*Table; void destroy_map () Does the erase() invalidate the iterator? This was the code I found free the memory pointed by the elements and then just clear() the map, given that you are.
    I have a map in which my value is dynamically allocated.

    That's just my opinion. Take a deep breath and you will realize how silly it is to imply that initialize-on-first-use is "complicated and obtuse". I suppose the assignment could throw inside the destructor. They will destroy the objects you put into them. Custom Filters release announcement. Checking pointers for null values all the time if they're never supposed to be null is a cargo-cult form of robustness.

    images std map erase free memory
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    Thanks for the explanation. And that's your answer. To me, all of the above, together, are enough to merit the name "dirty hack". Now, if you want to specify the log-file at startup, then that's trivial. STL containers won't manage your memory, so ensure you do it.

    images std map erase free memory

    Joel Yliluoma.

    (std::remove_if((), (), [](int i){ return i % 2 == 0;}), vec. end()); But for vector of pointers this is not as straightforward, since memory . How to Remove Elements from an Associative Container (maps and sets) Get a free ebook of more than 50 pages that will teach you the basic. References and iterators to the erased elements are invalidated.

    Other references and iterators are not affected.

    Video: Std map erase free memory Learn STL: Removing Elements 1

    The iterator pos must be valid. Does std::() properly delete pointers, or does it create memory leaks? Q2. Without knowing if erase() removes pointers properly or.
    At the same time, you need the variable to be global, because passing it as a parameter to everything is insane. Thanks for pointing it out, I fixed this. Now, if you want to specify the log-file at startup, then that's trivial.

    c++ map erase() Stack Overflow

    Also, if you have to initialize a logger in the main function anyway, we're talking about a more obscure kind of failure if you forget to do that than one which crashes immediately. Global scope means the variable's lifetime is that of the application, right?

    images std map erase free memory

    images std map erase free memory
    Std map erase free memory
    You can either make a dummy use of it at startup, just to ensure that it is initialized before entering any time-critical process.

    At least, that's my opinion, and I have used shared pointers a lot for that reason and it has made things dramatically better in terms of robustness AND performance because it avoids expensive workarounds to deal with raw pointers in a safe manner. The solution is simple: make your global object a global object. And, in this case, you need initialize-on-first-use.

    map erase() function in C++ STL GeeksforGeeks

    A std::map is something we would avoid, too. It definitely would. Post Reply.

    3 Replies to “Std map erase free memory”

    1. So, in either case, you either crash you application for a very stupid reason the constructor of a global object just wanted to log something, why does that have to crash your software!?! And that's your answer.

    2. Practically, of course, I wouldn't worry about it, and would do it as you suggest. The bad thing is that you need to use additional libraries, such as boost.