FIX: Compiler Incorrectly Causes Default Constructor Reference

• The C/C++ Compiler (CL.EXE), included with:
  • Microsoft Visual C++, 32-bit Editions, version 5.0

SYMPTOMS

When instantiating a class template with a member function that has a default parameter, error C2512 may be generated.

CAUSE

This behavior can occur when the default parameter is an explicitly-created temporary of the parameterized type of the template. The sample code below demonstrates this.

RESOLUTION

Do not use an explicitly-generated temporary as a default argument.

-or-

Ensure that the template argument has a default constructor available.

STATUS

Microsoft has confirmed this to be a bug in the Microsoft products listed at the beginning of this article. This bug has been fixed in Visual Studio 97 Service Pack 3.

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

Q170365 INFO: Visual Studio 97 Service Packs - What, Where, and Why

MORE INFORMATION

Sample

   // compile options : /c
   template<typename T>
   class C
   {
   public:
       void fn(const T & t = T());
   };
   class X
   {
   public:
       X(int);
       ~X();
   };
   C<X> l; 

Additional query words:

Keywords : kbCompiler kbCPPonly kbVC500bug kbVS97sp2fix
Version : WINNT:5.0
Platform : winnt
Issue type : kbbug