garbage collector c++

Question

I've been trying to create a garbage collector in c++, i've designed it as a base class to all of mine, called garbageCandidate, which holds a static vector containing pointers to garbageCandidate with every garbageCollector instance pushing "this" on the vector.

Then a static function comes and delete all the pointers in the static vector.

At the very begining of the deleting function (delete on first pointer) i get an error stating delete was used on invalid pointer...

Does this have to do with static/dynamic binding? I mean : is the delete operator unable to act as expected since i call delete on a "father" class and it is in fact a child ?

Could a way of avoiding this be to create virtual destructors? (or a virtual delete function)?

or did i completely missed something?

ps:all objects used for test where created dynamically.

Answer 1

Is there a reason you're rolling your own custom garbage collector? If all your objects are created dynamically, then why aren't you using boost's smart pointers (like boost::shared_ptr) which essentially uses RAII to give you a well tested garbage collection solution?

I ask because usually in the course of software development life cycle of a project, you end up fixing bugs in the code you wrote yourself (most of the time, at least). So is there a reason you're re-inventing the wheel?

Answer 2

Rather than rolling your own GC, I think you should be using the Boehm Conservative GC or smart pointers. Neither is perfect:

• The Boehm Collector requires you to use special allocate and (if you use it) deallocate methods, and getting existing libraries to play along can require some effort:

  • C++ standard library and Boehm garbage collector

  • Is it possible to use Boehm garbage collector only for the part of the program?

• Smart pointers add an overhead each time that you assign a pointer to a variable. They don't deal with object networks that have pointer cycles in them. You need to manually break the cycles to allow the objects reachable from them to be collected.

In spite of this, either of Boehm GC or Smart pointers would be less implementation and maintenance effort than rolling your own solution.