Re: strange crush when using template singleton class

"Carl Daniel [VC++ MVP]" <>
Sat, 17 Mar 2007 09:13:40 -0700
andrew wrote:

Do you have any idea why the crush occurs ?
Or, can you give me some hints \ ideas how to debug this ?

Obviously the code you've posted here isn't the code you're running, since
the code you've posted won't compile. Can you post a minimal and complete
program that illustrates the problem? Frequently during the exercise of
reducing the problem to it's minimal form you'll discover what the problem
really is.

What compiler version are you using? Exactly what compiler options are you
building with? (If you're building from the IDE, you can get the exact
command line options from the project properties dialog).

I tried the minimal program below with VC 2005 with a variety of options and
was unable to reproduce the crash you describe.

#include <windows.h>
#include <atlbase.h>
#include <stdio.h>

template<class T>
class CSingleton
 static T* Instance()
  static T obj;
  return &obj;

 CSingleton() {}

 CSingleton& operator=(const CSingleton&);
 CSingleton(const CSingleton&);

class SomeClass1 : public IUnknown
 ULONG __stdcall AddRef() { return 1; }
 ULONG __stdcall Release() { return 0; }
 HRESULT __stdcall QueryInterface(REFIID riid, void**ppv)
  return E_NOTIMPL;

class SomeClass2 : public SomeClass1

class CMyClass : public CSingleton<CMyClass>
    friend class CSingleton<CMyClass>;

          CMyClass() { }

           CComPtr<SomeClass1> m_pObj1;
           CComPtr<SomeClass2> m_pObj2;

           int m_var;
       void Init(SomeClass1* pParam) { m_pObj1 = pParam; m_var = 0; }
        void Do() { }

int main()
 printf("Before Init\n");
 CMyClass::Instance()->Init(new SomeClass1());
 printf("Before Do\n");
 printf("After Do\n");


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