无法从C ++中的向量中删除void指针

Question

hi everybody im trying to delete void pointer from vector, the program crash in the delete. thank you very much!

template <class T> class tArray_t : public vpArr_t {
  virtual ~tArray_t() {

   for (vector<void*>::iterator it = array.begin() ; it != array.end(); )
   {
          vector<void*>::iterator nextElement = it+1;
          delete *it; // here is the crash
          it = nextElement; 
   }

};

Answer 1

Deleting void pointers is undefined . You are getting exactly what you have asked for.

Use vector<T*> instead of vector<void*> . If you eg have vector<void*> inherited from your base class, you have to cast the pointer to T* before deleting it.

delete static_cast<T*>(*it);

You may also want to save you some work and use boost::ptr_vector .

Answer 2

Compiler know how many bytes to be deleted with a typed pointer. Think of it this way, a void * pointer doesn't have any information about the memory it pointing to, nobody knows how to delete a pointer like this. To the minimum, you don't know what size needs to be deleted, and no information about which destructor to call.

Class A;
A * p = new A();
delete p;

When delete p is executed, compiler knows A destrcutor needs to be called, and the size of memory needs to be cleaned up is sizeof(A). A void * pointer is missing all this information.