Q216731: FIX: Dtor of Explicitly Constructed Anonymous Temp Not Called

Article: Q216731
Product(s): Microsoft C Compiler
Version(s): winnt:6.0
Operating System(s): 
Keyword(s): kbservicepack kbCompiler kbCPPonly kbVC600bug kbVC600fix kbVS600sp2 kbVS600SP1 kbVS600s
Last Modified: 07-MAY-2001

-------------------------------------------------------------------------------
The information in this article applies to:

- Microsoft Visual C++, 32-bit Enterprise Edition, version 6.0 
- Microsoft Visual C++, 32-bit Professional Edition, version 6.0 
- Microsoft Visual C++, 32-bit Learning Edition, version 6.0 
-------------------------------------------------------------------------------

SYMPTOMS
========

When an explicitly constructed anonymous temporary of template type that has a
default constructor with a default argument is used in an expression, it is
never destroyed.

STATUS
======

Microsoft has confirmed this to be a bug in the Microsoft products listed at the
beginning of this article.

This bug was corrected in Visual Studio 6.0 Service Pack 3. For more information
about Visual Studio service packs, please see the following articles in the
Microsoft Knowledge Base:

  Q194022 INFO: Visual Studio 6.0 Service Packs, What, Where, Why

  Q194295 HOWTO: Tell That Visual Studio 6.0 Service Packs Are Installed

MORE INFORMATION
================

Sample Code
-----------

  #include <stdio.h>
  const int ex = 4;

  template<typename T>
  struct CPtr {
      CPtr(int e = ex) {
  		m_ptr = new T();
  		printf("In CPtr::CPtr()\n");
  	}

      T *operator->() const {
  		return m_ptr;
  	}

  	~CPtr() {
  		printf("In CPtr::~CPtr()\n");
  	}

  	T *m_ptr;
  };

  struct I {
  	int mf() {return 1;}
  };

  int main()
  {
  	bool fFlag = false;
  	if ((CPtr<I>()->mf() < 0) && !fFlag) return 1;
  	return 0;
  }

The output is:

  In CPtr::CPtr()

The output should be:

  In CPtr::CPtr()
  In CPtr::~CPtr()

Additional query words:

======================================================================
Keywords          : kbservicepack kbCompiler kbCPPonly kbVC600bug kbVC600fix kbVS600sp2 kbVS600SP1 kbVS600sp3fix 
Technology        : kbVCsearch kbAudDeveloper kbVC600 kbVC32bitSearch
Version           : winnt:6.0
Issue type        : kbbug
Solution Type     : kbfix

=============================================================================

THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY.

Copyright Microsoft Corporation 1986-2002.