Re: friend operator new/delete - allow obj instantiation only in heap - howto?

From:
ajk <usenetonly@doh.com>
Newsgroups:
comp.lang.c++
Date:
Thu, 26 Apr 2007 12:20:34 GMT
Message-ID:
<c36133tbjsqnvnhi4f2f45l83pecippnug@4ax.com>
On 25 Apr 2007 02:58:47 -0700, WittyGuy <wittyguysuku@gmail.com>
wrote:

Hi all,
All I want to achieve is restricting the object instantiation in stack
and allowing the application to instantiate the object only in heap
using new operator. How to achieve this?

I tried out with the following code.
Could you please give me the reason for the compilation error for the
following code:

#include <iostream>

class Temp
{
public:
   friend void* ::operator new (size_t);
   friend void ::operator delete (void* pDel);
private:
   Temp ()
   {
       std::cout << "Temp Ctor" << std::endl;
   }
   ~Temp ()
   {
       std::cout << "Temp Dtor" << std::endl;
   }
};

int
main ()
{
   Temp *pT = new Temp;
   delete pT;

   // Temp tempObj; // Should be disallowed
   return 0;
}

Compilation error received:
---------------------------------------
heap.cpp: In function 'int main()':
heap.cpp:9: error: 'Temp::Temp()' is private
heap.cpp:22: error: within this context
heap.cpp:13: error: 'Temp::~Temp()' is private
heap.cpp:23: error: within this context

Please help me in instantiating the Temp object only in heap, not in
stack.

thanks
Sukumar R


class Temp {
public:
 ~Temp() { ; }
  auto_ptr<Temp> getInstance() { return new Temp; }
private:
  Temp() { ; }
};

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