Q115521: FIX: Private Copy Constructor Called Without Proper Access

Article: Q115521
Product(s): Microsoft C Compiler
Version(s): 1.0,1.5,2.0,4.0,4.1,7.0
Operating System(s): 
Keyword(s): kbtool kbCompiler kbCPPonly kbVC kbVC500fix
Last Modified: 11-FEB-2002

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The information in this article applies to:

- Microsoft C/C++ Compiler (CL.EXE), included with:
   - Microsoft C/C++ for MS-DOS, version 7.0 
   - Microsoft Visual C++, versions 1.0, 1.5 
   - *EDITOR Please do not choose this product*Microsoft Visual C++ 32-bit Edition* use 241, 265, 225, versions 1.0, 2.0, 4.0, 4.1 
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SYMPTOMS
========

After declaring the only copy constructor in a class with an access of
"private", the constructor is called when access should not be allowed. For
example, when an instance of the class is passed as a parameter to a function,
the copy constructor is used to initialize the parameter; this should be allowed
only if the function has "private" access.

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 C++ version 5.0.

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

The following sample code demonstrates this problem.

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

     /* Compile options needed: none
     */ 

        #include <iostream.h>

        class aClass
        {
        private:
            int i;
            aClass(const aClass& x) { cout << "private copy constructor" <<
        endl; };

        public:
            aClass(int j) : i(j) {};
        };

        int func(aClass x) { return 0; };

        int main(void)
        {
            int n;
            aClass a(1);

            n = func(a);  //Copy constructor gets called anyway.

            return 0;
        }

Additional query words: kbVC400bug 8.00 8.00c 9.00

======================================================================
Keywords          : kbtool kbCompiler kbCPPonly kbVC kbVC500fix 
Technology        : kbVCsearch kbAudDeveloper kbCVCComp
Version           : :1.0,1.5,2.0,4.0,4.1,7.0
Issue type        : kbbug
Solution Type     : kbfix

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