FIX: C2065: Undeclared Identifier Creating a STL Function Object (177431)


The information in this article applies to:

  • Microsoft Visual C++, 32-bit Enterprise Edition 5.0
  • Microsoft Visual C++, 32-bit Professional Edition 5.0
This article was previously published under Q177431

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 ;
   }
Modification Type:MajorLast Reviewed:10/24/2003
Keywords:kbbug kbfix kbVC600fix KB177431
©2003 Microsoft Corporation. All rights reserved.