BUG: Error C2011 When Reusing Nested Structure Tag Names (201830)

The information in this article applies to:

Microsoft Visual C++, 32-bit Editions 2.0
Microsoft Visual C++, 32-bit Editions 4.0
Microsoft Visual C++, 32-bit Enterprise Edition 5.0
Microsoft Visual C++, 32-bit Professional Edition 5.0
Microsoft Visual C++, 32-bit Enterprise Edition 6.0
Microsoft Visual C++, 32-bit Professional Edition 6.0
Microsoft Visual C++, 32-bit Learning Edition 6.0

This article was previously published under Q201830

SYMPTOMS

When the same tag name is used to declare nested structures inside different base structure declarations, the follow error is generated:

error C2011: '<identifier>' : '<type>' type redefinition

NOTE: The C++ compiler does not generate this error.

RESOLUTION

To work around this problem, either don't use tag names for nested structures, or use unique tag names for all structures.

STATUS

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

MORE INFORMATION

The following code fails to compile with the C compiler. Error C2011 is reported at the second use of "tag_LEVEL2" and "tag_LEVEL3". This error does not occur using the C++ compiler.

/* Defining "A" structure */ 
struct tag_STRUCTA {

   struct tag_LEVEL2 {
      int   member_a2;

      struct tag_LEVEL3 {
         int member_a3;
      };
   };
};

/* Defining "B" structure */ 
struct tag_STRUCTB {

   struct tag_LEVEL2 {
      int   member_b2;
   };
   struct tag_LEVEL3 {
      int member_b3;
   };
};

Modification Type:	Minor	Last Reviewed:	7/5/2005
Keywords:	kbbug kbConly kbnofix KB201830