Q177431: FIX: C2065: Undeclared Identifier Creating a STL Function Object

Article: Q177431
Product(s): Microsoft C Compiler
Version(s): 5.0
Operating System(s): 
Keyword(s): kbVC600fixkbbuglist
Last Modified: 07-MAY-2001

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The information in this article applies to:

- Microsoft Visual C++, 32-bit Enterprise Edition, version 5.0 
- Microsoft Visual C++, 32-bit Professional Edition, version 5.0 
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SYMPTOMS
========

Creating the STL function object "binder2nd" causes the compiler to generate the
following error C2065:

  'identifier' : undeclared identifier

It is the std::multiples<int>(): line that causes the namespace to be lost.

RESOLUTION
==========

Use one of the following methods to work around this problem:

- Use the "using namespace" directive instead of qualifying the function
  objects.

- Pre-declare an instance of std::multiplies<int> to solve the problem.

STATUS
======

Microsoft has confirmed this to be a bug in the Microsoft product listed at the
beginning of this article. This problem was corrected in Visual C++ version 6.0
for Windows.

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

The following sample demonstrates the problem and the first workaround:

     /*
     * Compiler Options: /GX
     */ 

     #include <algorithm>
     #include <functional>
     #include <iostream>

     #define BUG
     //Workaround: Comment the line above.
     //Uncomment the line below.
     //#define WORKAROUND

     #ifdef WORKAROUND
     using namespace std ;
     #endif

     int main()
     {

     #ifdef BUG

        std::binder2nd< std::multiplies<int> >
                       times_two(std::multiplies<int>(), 2);
     #endif
     #ifdef WORKAROUND
         binder2nd< multiplies<int> > times_two(multiplies<int>(), 2);
     #endif

        int n = times_two(4) ;
        std::cout << "n = " << n << std::endl ;
        return 0 ;
     }

The following sample demonstrates the problem and the second workaround:

     /*
     * Compiler Options: /GX
     */ 

     #include <algorithm>
     #include <functional>
     #include <iostream>

     #define BUG
     //Workaround: Comment the line above.
     //Uncomment the line below.
     //#define WORKAROUND

     int main()
     {

     #ifdef BUG

        std::binder2nd< std::multiplies<int> >
                       times_two(std::multiplies<int>(), 2);

     #endif

     #ifdef WORKAROUND

        std::multiplies<int> mi ;
        std::binder2nd< std::multiplies<int> > times_two(mi, 2);

     #endif

        int n = times_two(4) ;
        std::cout << "n = " << n << std::endl ;
        return 0 ;
     }

Additional query words:

======================================================================
Keywords          : kbVC600fix kbbuglist
Technology        : kbVCsearch kbAudDeveloper kbVC500 kbVC32bitSearch kbVC500Search
Version           : :5.0
Issue type        : kbbug
Solution Type     : kbfix

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