virtual ~IScriptEngine() {}

class CObject {
    int a;
 };

class IScriptEngine {
    int b;
 };

class CScriptEngine : public CObject, public IScriptEngine {
    int c;
 };

int main()
{
IScriptEngine* m_ScriptEngine = new CScriptEngine;

delete m_ScriptEngine;

return 0;
}

$ g++ test.cpp

$ valgrind ./a.out

==27318== Memcheck, a memory error detector
==27318== Copyright (C) 2002-2009, and GNU GPL'd, by Julian Seward et al.
==27318== Using Valgrind-3.5.0 and LibVEX; rerun with -h for copyright info
==27318== Command: ./a.out
==27318==
==27318== Invalid free() / delete / delete[]
==27318==    at 0x402354D: operator delete(void*) (vg_replace_malloc.c:346)
==27318==    by 0x804853C: main (in /home/nick/development/a.out)
==27318==  Address 0x42bb02c is 4 bytes inside a block of size 12 alloc'd
==27318==    at 0x40243A0: operator new(unsigned int) (vg_replace_malloc.c:214)
==27318==    by 0x8048510: main (in /home/nick/development/a.out)
==27318==
==27318==
==27318== HEAP SUMMARY:
==27318==     in use at exit: 12 bytes in 1 blocks
==27318==   total heap usage: 1 allocs, 1 frees, 12 bytes allocated
==27318==
==27318== LEAK SUMMARY:
==27318==    definitely lost: 12 bytes in 1 blocks
==27318==    indirectly lost: 0 bytes in 0 blocks
==27318==      possibly lost: 0 bytes in 0 blocks
==27318==    still reachable: 0 bytes in 0 blocks
==27318==         suppressed: 0 bytes in 0 blocks
==27318== Rerun with --leak-check=full to see details of leaked memory
==27318==
==27318== For counts of detected and suppressed errors, rerun with: -v
==27318== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 17 from 6)

IScriptEngine* IScriptEngine::Create (const CString& language, CMUSHclientDoc* pDoc)
{
  if (language.CompareNoCase ("Lua") == 0)
    return new LuaScriptEngine (pDoc);
  else
    return new CScriptEngine (pDoc, language);
}

  auto_ptr<LuaScriptEngine> m_ScriptEngine = NULL; // for the filtering checks

  bool bFiltering = GetFilterFlag ();
  if (bFiltering)
    {
    try
      {
      m_ScriptEngine = new LuaScriptEngine (m_doc);

      if (m_ScriptEngine->Parse ((LPCTSTR) GetFilterScript (), "Script file"))
        bFiltering = false;
      }
    catch (ScriptEngineException& ex)
      {
      bFiltering = false;
      }
    catch (CException* e)
      {
      e->ReportError ();
      e->Delete ();
      bFiltering = false;
      }
    }  // end of filtering wanted