Q149965: FIX: C2668 in Overloaded Function When enum Is Promoted to int

Article: Q149965
Product(s): Microsoft C Compiler
Version(s): 1.0,1.5,1.52,2.0,2.1,2.2,4.0,4.1,4.2
Operating System(s): 
Keyword(s): kbCompiler kbCPPonly kbVC kbVC500fix
Last Modified: 30-JUL-2001

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The information in this article applies to:

- Microsoft C/C++ Compiler (CL.EXE), used with:
   - Microsoft Visual C++, versions 1.0, 1.5, 1.52 
   - *EDITOR Please do not choose this product*Microsoft Visual C++ 32-bit Edition* use 241, 265, 225, versions 2.0, 2.1, 2.2, 4.0, 4.1, 4.2 
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SYMPTOMS
========

When a function is overloaded to take an int parameter in one instance and an
unsigned int in another, the following error results if a call to the function
is made with an enumerated type:

  C2668 error: 'func' : ambiguous call to overloaded function (new behavior;
  please see help)

RESOLUTION
==========

- Use a cast when calling the function, such as func((unsigned)y).

-or-

- Overload the function to take the enumerated type, such as:

     func(enum A);
     func(enum E);

STATUS
======

Microsoft has confirmed this to be bug in the Microsoft products listed at the
beginning of this article. This bug was corrected in Visual C++ version 5.0.

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

Sample Code to Demonstrate Problem
----------------------------------

     // Compile option needed: none

     enum A{eA = 0, eB};
     enum E{e = -1};

     void func(int a);
     void func(unsigned int a);

     void main(){
                A y = eA;
                E e1 = e;
                int m = 2;

                func(m);        // calls func(int)
                func(y);        // C2668 error
                func(e1);       // C2668 error
              }

Additional query words: kbVC400bug

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Keywords          : kbCompiler kbCPPonly kbVC kbVC500fix 
Technology        : kbVCsearch kbAudDeveloper kbCVCComp
Version           : :1.0,1.5,1.52,2.0,2.1,2.2,4.0,4.1,4.2
Issue type        : kbbug
Solution Type     : kbfix

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