memory management - How do I create an array or list of externally managed objects in modern c++? -


i building add-in program. add-in manipulates ptr objects passed me host application. create vector of externally created , managed objects host. unfortunately, documentation doesn't have clear examples of how this. 

class players {     vector<ptr<player>> vectorofgamers; // deletes , when this?       public void createplayers () {     // call static application create 3 players     ( int = 0; < 3; i++ )        vectorofgamers.push_back(application.getnextplayer());       }   }

confused how build class , prevent memory leaks , causing null exception if items deleted prematurely. also, how use modern c++ facilities achieve yet gain of benefits of new memory management make_shared, make_unique, nullptr, etc?

for information, below snapshot of ptr.i confused ptr appears superfluous given modern c++'s new memory management facilities.

class incompletetype { public:     template<typename t> static void addref(void* ptr) { reinterpret_cast<adsk::core::referencecounted*>(ptr)->addref(); }     template<typename t> static void release(void* ptr) { reinterpret_cast<adsk::core::referencecounted*>(ptr)->release(); } };  class completetype { public:     template<typename t> static void addref(t* ptr) { ptr->addref(); }     template<typename t> static void release(t* ptr) { ptr->release(); } };  template<class t, class pt = incompletetype> class ptr { public:      typedef t element_type;      ptr() : ptr_(nullptr) {}     ptr(const ptr& rhs) : ptr_(nullptr) { reset(rhs.ptr_); }     ptr(const t* ptr, bool attach = true) : ptr_(nullptr) { reset(ptr, attach); }      // casting constructor.  call operator bool verify if cast successful     template<class v, class vpt>     ptr(const ptr<v, vpt>& rhs) : ptr_(nullptr) {         if (rhs)             reset(rhs->template query<t>(), false);     }      ~ptr() { reset(nullptr); }      void operator=(const ptr<t, pt>& rhs) { if (&rhs != this) reset(rhs.ptr_); }     void operator=(const t* ptr) { reset(ptr, true); }      // casting assignment operator.  call operator bool verify if cast successful     template<class v, class vpt>     void operator=(const ptr<v, vpt>& rhs) {         if (rhs)             reset(rhs->template query<t>(), false);         else             reset(nullptr);     }      void reset(const t* ptr, bool attach = false) {         if (ptr_ != ptr)         {             if (ptr_)                 pt::template release<t>(ptr_);             ptr_ = const_cast<t*>(ptr);             if (!attach && ptr_)                 pt::template addref<t>(ptr_);         }     }      t* operator->() const { assert(ptr_ != nullptr); if (ptr_ == nullptr) throw std::exception(); return ptr_; }      // test if pointer empty (if operator-> throw)     /*explicit*/ operator bool() const { return ptr_ != nullptr; }      bool operator==(const ptr& rhs) const { return ptr_ == rhs.ptr_; }     bool operator!=(const ptr& rhs) const { return ptr_ != rhs.ptr_; }     bool operator<(const ptr& rhs) const { return ptr_ < rhs.ptr_; }       // iteration support.  usable if t has count , item members , iterable_type     typedef iterator<t, pt> iterator;     iterator begin() const { return iterator<t, pt>(*this); }     iterator end() const { return iterator<t, pt>(*this, true); }      // caution following functions if used incorrectly can cause reference count leak     t* get() const { return ptr_; }     t* detach() { t* t = ptr_; ptr_ = nullptr; return t; }  private:      t* ptr_; };

you’re right ptr wouldn’t needed in post-c++03 environment. plugin api old enough c++11 wasn’t around then. code posted best guess ptr supposed reference counted smart pointer manages shared ownership std::shared_ptr does.

how use thing should become clear plguin api documentation , maybe source code of host program. snippet posted , without mentioning program’s name it’s impossible definite.


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