FIX: Template Keyword Can't Be Used Inside Class Declarations

• The Microsoft C/C++ Compiler (CL.EXE) included with: - Microsoft Visual C++, 32-bit Edition, versions 4.0, 4.1, 4.2

SYMPTOMS

Any attempt to use the keyword 'template' within a class definition results in the following two errors:

  error C2059: syntax error : 'template'
  error C2238: unexpected token(s) preceding ';'

RESOLUTION

The resolution will vary according to the circumstances. For example, when declaring a template function to be a friend of a non-template class, find another way to manipulate the members of the class; for example, declare them to be public instead of private or provide public access member functions.

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.

MORE INFORMATION

Examples where you need to use the keyword template within a class definition include:

• Declaring a template function to be a friend of a non-template class.
• Declaring a template class to be a friend of a non-template class.
• Declaring a template function as a member of a non-template class.

Sample Code

   /* Compile options needed: None
      This sample illustrates the case of declaring a template function
      to be a friend of a non-template class.
   */

   class A;
   template <class T> void f(T, A *a)  { a->x; }

   class A {
   private:
       int x;
       template <class T> friend void f(T, A*);
   };