BUG: C2099 Generated Initializing Struct with Macro

• The Microsoft C/C++ Compiler (CL.EXE) included with - Microsoft C/C++ version 7.0 - Microsoft Visual C++ for Windows, versions 1.0, 1.5 - Microsoft Visual C++ 32-bit Edition, versions 1.0, 2.0, 4.0, 4.1, 4.2,

       5.0
  

SYMPTOMS

Using a macro to initialize a structure causes the C/C++ compiler to incorrectly generate the following error message:

   error C2099: initializer is not a constant

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

The sample code below can be used to reproduce this problem:

Sample Code

   /* Compile options needed: none
   */

   #include <stddef.h>

   #define ZIP     struct zip_struct
   #define ZOT     struct zot_struct
   #define TABLE   struct table_struct

   ZIP
   {
      ZOT
      {
         int num;
      } m_zot;
   };


   #define MACRO(tok) \
      { (offsetof(ZIP, m_zot.tok) - offsetof(ZIP, m_zot)) / sizeof(int) }

   TABLE
   {
      int Offset;
      int ModNum;
   };

   TABLE test[] = { { offsetof(ZIP, m_zot.num) - offsetof(ZIP, m_zot)
                    / sizeof(int) } };
   TABLE test2[] = { { MACRO(num) } };

   void main(void)
   {
   }