BUG: ClassView Cannot Find Template Member Function Definition

• Microsoft Visual C++, 32-bit Editions, versions 4.0, 4.1, 4.2, 6.0

SYMPTOMS

ClassView pops up the message "Cannot find the definition for this function" for some member functions of a template class. This happens for those member functions that return a template class, or a reference or pointer to a template class. The function must also be defined outside of the class. The sample code in the More Information section below demonstrates this problem.

In Visual C++, version 6.0, ClassView cannot find any template member function or variable defined outside of the class. The error message reads:

Cannot find the definition (implementation) of this function.

RESOLUTION

The only workaround is to define the function inline by moving its body inside the class declaration. Note that defining the function outside the class declaration with the inline keyword will not solve the problem. Also note that projects with this problem will still build and run correctly; only the convenience of finding a function's definition via the ClassView is lost.

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.

This bug reappeared in Microsoft Visual C++, version 6.0.

MORE INFORMATION

The following sample code will reproduce the problem. To reproduce, right click on "mult_by_scalar" while in the class view and select Go To Definition.

For additional information, please see the following article in the Microsoft Knowledge Base:

Q179012 ClassView Lacks "Go to Declaration" for Static Data Members

Sample Code

   /* Compile options needed:none
   */ 

   template<class T>
   class SimpleArray {

   public:

       SimpleArray();
       ~SimpleArray();

       SimpleArray<T>& mult_by_scalar(T);// Cannot find the definition

       int Numelem();

   private:
       int num_elts;
       T* ptr_to_data;

   };

   template <class T>
   SimpleArray<T>::SimpleArray() {
       num_elts=0;
       ptr_to_data = 0;
   }

   template <class T>
   SimpleArray<T>::~SimpleArray() {
       delete [] ptr_to_data;
   }

   template <class T>
   SimpleArray<T>& SimpleArray<T>::mult_by_scalar(T rm) {

        return *this;
   }

   template <class T>
   int SimpleArray<T>::Numelem(){

       return  num_elts;
   } 

Keywords : kberrmsg kbui kbCompiler kbCPPonly kbVC kbVC400bug kbVC410bug kbVC420bug kbVC500fix kbVC600bug kbGrpDSTools
Version : 4.0 4.1 4.2 6.0
Platform :
Issue type :