BUG: Default Constructor Argument Cannot Use Namespace Scope

• Microsoft Visual C++, 32-bit Editions, version 5.0

SYMPTOMS

When you give the default argument value for a class constructor a value that references a namespace via the '::' operator, a C2065 error occurs as follows:

   [FileName](12) : error C2065: 'inside' : undeclared identifier

RESOLUTION

To work around this, use either the using directive to instruct the compiler to consider the namespace as a possible place to find all symbols, or the using declaration to tell the compiler to consider the namespace for the specific symbol that is referenced by the default argument. Please see the workarounds noted in the sample code below. Note that these workarounds make it unnecessary to use the '::' operator to explicitly reference the namespace, but it is also not necessary to remove it.

STATUS

Microsoft has confirmed this to be a bug in the Microsoft products listed at the beginning of this article. We are researching this bug and will post new information here in the Microsoft Knowledge Base as it becomes available.

MORE INFORMATION

Sample Code

   /* Compile Options Needed: None */
   namespace MyNameSpace {
   int inside = 34;
   };

   // Uncomment the following to workaround via the using declaration
   //using MyNameSpace::inside;
   // Uncomment the following to workaround via the using directive
   //using namespace MyNameSpace;

   class MyClass {
   public:
   MyClass(int iVal = MyNameSpace::inside);
   };

   [FileName](12) : error C2065: 'inside' : undeclared identifier