Microsoft KB Archive/92617

From BetaArchive Wiki

BUG: C1001 Error From Complex Structure Declaration


The information in this article applies to:

  • The Microsoft C/C++ Compiler (CL.EXE),
    • Microsoft C/C++ for MS-DOS, version 7.0
    • Microsoft Visual C++, versions 1.0, 1.5


The compiler generates a "fatal error C1001: INTERNAL COMPILER ERROR" message when compiling the declaration of a struct that contains a union that contains a struct that contains an array of 65,535 characters.


Microsoft has confirmed this to be a bug in the 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.

This is not a problem in Visual C++ 32-bit Edition.


This error does not appear to be influenced by optimizations, memory model or using the fast compile option. The code compiles correctly when the size of the array is changed to 65,534 or fewer elements or if the outer struct declaration is removed.

Compiling the following code demonstrates the Internal Compiler Error.

Sample Code

 * Compile options needed: none
struct D
   union C
      struct E
         char a[65535];
      } e;
      struct F
         int b[20];
      } f;
   } c;
} d; 

Additional query words: 7.00 8.00 8.00c 1.00 1.50

Keywords : kb16bitonly
Issue type :
Technology :

Last Reviewed: May 8, 2001
© 2001 Microsoft Corporation. All rights reserved. Terms of Use.