Q122443: FIX: C2664 When Converting Type Defined Array to Const Array

Article: Q122443
Product(s): Microsoft C Compiler
Version(s): 2.0
Operating System(s): 
Keyword(s): kbbuglist kbfixlist
Last Modified: 23-JUL-2001

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The information in this article applies to:

- Microsoft C/C++ Compiler (CL.EXE), included with:
   - *EDITOR Please do not choose this product*Microsoft Visual C++ 32-bit Edition* use 241, 265, 225, version 2.0 
-------------------------------------------------------------------------------

SYMPTOMS
========

The C/C++ compiler incorrectly generates a C2664 error when attempting to
implicitly convert from a typedef non-constant array type to a constant array
type. The compiler reports an error that indicates a conversion from a constant
array type to a non-constant array type. The following error message is reported
by the compiler if a non-constant integer array type is used:

  test.cpp(#): error C2664: 'copy' : cannot convert parameter 1 from 'const
  int[2]' to 'int[2]'

The # is the line number where the error occured.

RESOLUTION
==========

To work around the problem, typedef a constant array type instead of using the
keyword 'const' together with the typedef non-constant array type. An example is
shown in the Sample Code section in this article.

STATUS
======

Microsoft has confirmed this to be a bug in the Microsoft products listed at the
beginning of this article. This bug was corrected in Microsoft Visual C++,
32-bit Edition, version 4.0.

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

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

  /* Compile options needed: none
  */ 

  /* -- test.cpp -- */ 

  typedef       int ARRAY[2];
  typedef const int CONST_ARRAY[2];

  void copy ( const ARRAY src, ARRAY dest );
  void copy1( CONST_ARRAY src, ARRAY dest );

  class CTest
  {
    private:
      ARRAY pts[2];
    public:
      void operator=( const CTest& src );
  };

  void CTest :: operator=( const CTest& src )
  {
    for ( int i=0; i<2; i++ )
    {

     copy ( src.pts[i], pts[i] );   // Generates C2664
     copy1( src.pts[i], pts[i] );   // Workaround

    }
  }

Additional query words: 2.00 9.00 buglist2.00

======================================================================
Keywords          :  kbbuglist kbfixlist
Technology        : kbVCsearch kbAudDeveloper kbCVCComp
Version           : :2.0
Issue type        : kbbug
Solution Type     : kbfix

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

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