Q66775: PRB: L2029/L2001 Unsized Array Declaration at File Scope [utilit

Article: Q66775
Product(s): Microsoft C Compiler
Version(s): 1.0,1.5,2.0,4.0,5.0,5.1,5.1a,6.0,6.0a,6.0ax,7.0
Operating System(s): 
Keyword(s): kbVC100 kbVC150 kbVC200 kbVC500 kbVC600
Last Modified: 27-MAR-2002

-------------------------------------------------------------------------------
The information in this article applies to:

- The Linker (LINK.EXE), included with:
   - Microsoft Visual C++ for Windows, 16-bit edition, versions 1.0, 1.5 
   - Microsoft Visual C++, 32-bit Editions, versions 1.0, 2.0, 4.0, 5.0, 6.0 
   - Microsoft C for MS-DOS, versions 5.1, 5.1a, 6.0, 6.0a, 6.0ax 
   - Microsoft C for OS/2, versions 5.1, 6.0, 6.0a 
   - Microsoft C/C++ for MS-DOS, version 7.0 
   - Microsoft Visual C++.NET (2002) 
-------------------------------------------------------------------------------

NOTE: Microsoft Visual C++ NET (2002) supported both the managed code model that is provided by the .NET Framework and the unmanaged native Windows code model. The information in this article applies to unmanaged Visual C++ code only.

SYMPTOMS
========

An attempt to link an application fails and Microsoft LINK generates the
following messages.

  With Microsoft C/C++ 16-bit compilers:

  L2029: unresolved external

  With Microsoft C/C++ 32-bit compilers:

  LNK2001: unresolved external symbol

CAUSE
=====

The application declares an unsized array at file scope, and does not contain
another declaration at file scope that specifies the size for the array.

RESOLUTION
==========

Modify the source code of one of the modules to declare the array with its
correct size at file scope.

MORE INFORMATION
================

Because an unsized array declaration at file scope is considered external, the C
compiler cannot determine whether or not the size is omitted intentionally, and
the compiler does not generate an error message.

The following sample code demonstrates this situation:

Sample Code
-----------

  int Array[];

  void main(void)
  {
     printf("%d.\n", Array);
  }

To address this situation, create another source file that declares Array to have
a size (for example, "int Array[2]"), and compile and link the two modules.

Additional query words:

======================================================================
Keywords          : kbVC100 kbVC150 kbVC200 kbVC500 kbVC600 
Technology        : kbVCsearch kbAudDeveloper kbLINKSearch kbLINK100 kbVCNET
Version           : :1.0,1.5,2.0,4.0,5.0,5.1,5.1a,6.0,6.0a,6.0ax,7.0
Issue type        : kbprb

=============================================================================

THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY.

Copyright Microsoft Corporation 1986-2002.