Q226110: FIX: Internal Compiler Error Creating Copy of Temporary Object

Article: Q226110
Product(s): Microsoft C Compiler
Version(s): 6.0
Operating System(s): 
Keyword(s): kbCompiler kbVC600bug kbNoUpdate
Last Modified: 10-FEB-2002

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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 
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SYMPTOMS
========

When creating an object that is a copy of a virtual function return value (a
temporary object) using the compiler-supplied copy constructor, you may get the
following error:

  test.cpp(22) : fatal error C1001: INTERNAL COMPILER ERROR
  (compiler file 'msc1.cpp', line 1794)
  Please choose the Technical Support command on the Visual C++
  Help menu, or open the Technical Support help file for more information

Please see the steps to reproduce in the More Information section below.

RESOLUTION
==========

There are four ways to get around the problem:

1. Explicitly Define a Copy Constructor. (See Workaround #1 in sample code
  below).

2. Remove the virtual keyword from the function which returns the value. (See
  Workaround #2 in sample code below).

3. Introduce a temporary variable to store the return value. (See Workaround #3
  in the sample code below).

4. Remove compiler support for synchronous (C++) exception handling. This is
  accomplished by removing /GX (the Visual Studio default) from your compile
  options. (See Workaround #4 in sample code below).

Workaround #1 is the recommended workaround whenever possible.

NOTE: If you define a copy constructor, you should also define an assignment
operator (operator=).

STATUS
======

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

This problem was corrected in Microsoft Visual C++ .NET.

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

  ////////////////////////////////////////////////////////////////////// 
  // cl /c /GX test.cpp
  // test.cpp(22) : fatal error C1001: INTERNAL COMPILER ERROR
  //  (compiler file 'msc1.cpp', line 1794) 
  //  Please choose the Technical Support command on the Visual C++ 
  //  Help menu, or open the Technical Support help file for more information
  ////////////////////////////////////////////////////////////////////// 
  class A
  {
    public:
      /* workaround #1, add an explicit copy constructor to class A */ 
      // A(A& a) {};
      ~A() {}; 
  };
  class B
  {
    public:
   /* workaround #2, remove virtual keyword from B::GetA */ 
      virtual A& GetA(void);
      void Func (void);
  };
  void B::Func (void)
  {
    A *att;
    att=new A(GetA());
    /* workaround #3, substitute the above line with the following two lines */ 
    //A tmp = GetA();
    //att=new A(tmp);
  }
  /* workaround #4, remove /GX compiler option */ 

Additional query words: Internal Compiler Error ICE C1001

======================================================================
Keywords          : kbCompiler kbVC600bug kbNoUpdate 
Technology        : kbVCsearch kbAudDeveloper kbVC600 kbVC32bitSearch
Version           : :6.0
Issue type        : kbbug
Solution Type     : kbfix

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