Should every class have a virtual destructor?

by

Every abstract class should either have a,

  • protected destructor, or,
  • virtual destructor.

If you’ve got a public non-virtual destructor, that’s no good, since it allows users to delete through that pointer a derived object. Since as we all know, that’s undefined behavior.

For an abstract class, you already need a virtual-table pointer in the object, so making the destructor virtual doesn’t (as far as I’m aware) have a high cost in terms of space or runtime performance. And it has the benefit that derived classes automatically have their destructors virtual (see @Aconcagua’s comment). Of course, you can also make the destructor protected virtual for this case.

For a non-abstract class not intended to be deleted through a pointer to it, I don’t think there’s good reason to have a virtual destructor. It would waste resources, but more importantly it would give users a wrong hint. Just think about what weird sense it would make to give std::iterator a virtual destructor.

More Related Contents:

  1. When to use virtual destructors?
  2. Why should I declare a virtual destructor for an abstract class in C++?
  3. Virtual destructor and undefined behavior
  4. When should your destructor be virtual? [duplicate]
  5. Are virtual destructors inherited?
  6. A short C++ program about the pointer
  7. Determine if int is not 0 with no if statements
  8. How to trim a std::string?
  9. round() for float in C++
  10. Why should the “PIMPL” idiom be used? [duplicate]
  11. Remove spaces from std::string in C++
  12. Why can’t I compile an unordered_map with a pair as key?
  13. Sorting zipped (locked) containers in C++ using boost or the STL
  14. error: request for member ‘..’ in ‘..’ which is of non-class type
  15. How to concatenate two strings in C++?
  16. Accessing inherited variable from templated parent class [duplicate]
  17. Rand() % 14 only generates the values 6 or 13
  18. C++ catch blocks – catch exception by value or reference? [duplicate]
  19. Exporting a C++ class from a DLL
  20. How do objects work in x86 at the assembly level?
  21. Efficient 128-bit addition using carry flag
  22. Can we write an EOF character ourselves?
  23. What is the difference between const_iterator and non-const iterator in the C++ STL?
  24. C++ string::find complexity
  25. How to profile memory usage?
  26. Initializer list not working with vector in Visual Studio 2012? [duplicate]
  27. cpu dispatcher for visual studio for AVX and SSE
  28. Where does gcc look for C and C++ header files?
  29. Why use !! when converting int to bool?
  30. generic way to print out variable name in c++

Leave a Comment