Q151167: BUG: LNK2001 Error for Static Member in Class Template

Article: Q151167
Product(s): Microsoft C Compiler
Version(s): winnt:2.0,2.1,2.2,4.0,4.1,4.2,5.0
Operating System(s): 
Keyword(s): kbCompiler kbCPPonly kbVC kbVC200bug kbVC210bug kbVC220bug kbVC400bug kbVC410bug kbVC42
Last Modified: 09-MAY-2001

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The information in this article applies to:

- Microsoft Visual C++, versions 2.0, 2.1, 2.2, 4.0, 4.1 
- Microsoft Visual C++, 32-bit Enterprise Edition, versions 4.2, 5.0 
- Microsoft Visual C++, 32-bit Professional Edition, versions 4.2, 5.0 
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SYMPTOMS
========

Linker error LNK2001 is generated for static member variables of nested classes
in class templates. The message states:

  error LNK2001: unresolved external symbol "public: static int
  Outer<int>::Inner::sobj"(?sobj@Inner@?$Outer@H@@2HA)

RESOLUTION
==========

Do not use static member variables in nested classes of class templates.

STATUS
======

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

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

The sample code below gives the error message LNK2001.

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

  /* Compile options needed: none
  */ 

  template<class T> class Outer
  {
  public:
      static T souter;

      class Inner
      {
      public:
          static T sobj;
      };
  };

  template <class T> double Outer<double>::souter = 1;

  template <class T> int Outer<int>::Inner::sobj = 5;

  void main()
  {
      double dval = Outer<double>::souter;

      int i = Outer<int>::Inner::sobj;
  }

Additional query words: kbVC400bug

======================================================================
Keywords          : kbCompiler kbCPPonly kbVC kbVC200bug kbVC210bug kbVC220bug kbVC400bug kbVC410bug kbVC420bug kbVC500bug 
Technology        : kbVCsearch kbVC400 kbAudDeveloper kbVC220 kbVC410 kbVC420 kbVC500 kbVC200 kbVC210 kbVC32bitSearch kbVC500Search
Version           : winnt:2.0,2.1,2.2,4.0,4.1,4.2,5.0
Issue type        : kbbug

=============================================================================

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