Q115705: BUG: Function Style Conversion Incorrectly Generates Errors

Article: Q115705
Product(s): Microsoft C Compiler
Version(s): 1.0,1.5,2.0,4.0,4.1,4.2,5.0,6.0
Operating System(s): 
Keyword(s): kbCompiler kbCPPonly kbVC kbVC100bug kbVC200bug kbVC400bug kbVC410bug kbVC420bug kbVC50
Last Modified: 11-FEB-2002

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

- The C/C++ Compiler (CL.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, 4.1, 4.2, 5.0, 6.0 
-------------------------------------------------------------------------------

SYMPTOMS
========

When calling a class conversion function within a macro, as shown in the code
below, the compiler may incorrectly generate the following errors:

  error C2061: syntax error : identifier 'timeVal'
  error C2066: cast to function type is illegal
  error C2059: syntax error : ')'

RESOLUTION
==========

Following are two possible workarounds for this problem:

- Use temporary variables to hold an intermediate result.

  unsigned int tmp1, tmp2;

  tmp1 = WORD(timeVal);
  tmp2 = WORD(dateVal);
  m_dwVal = MAKELONG(tmp1, tmp2);

-or-

- Use a type cast operator instead of a conversion operator.

  m_dwVal = MAKELONG((WORD)timeVal, (WORD)dateVal);

STATUS
======

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

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

The following sample code demonstrates this problem.

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

  /* Compile options needed: /c
  */ 

  typedef unsigned short      WORD;
  typedef unsigned long       DWORD;

  #define LONG long

  #define MAKELONG(low, high) ((LONG)(((WORD)(low)) |  \ 
                  (((DWORD)((WORD)(high))) << 16)))

  class CMyDate
  {
  public:
     operator WORD()
     {
        return m_wVal;
     }

  private:
     WORD m_wVal;
  };

  class CMyTime
  {
  public:
     operator WORD()
     {
        return m_wVal;
     }

  private:
     WORD m_wVal;
  };

  class CMyDateTime
  {
     CMyDateTime(CMyDate dateVal, CMyTime timeVal)
     {
        m_dwVal = MAKELONG(WORD(timeVal), WORD(dateVal));

     // This call works in both, even though it is identical.

        m_dwVal= MAKELONG(timeVal.operator WORD(), dateVal.operator
                 WORD());
     }

   private:
     DWORD m_dwVal;
  };

Additional query words: kbVC400bug 8.00 8.00c 9.00

======================================================================
Keywords          : kbCompiler kbCPPonly kbVC kbVC100bug kbVC200bug kbVC400bug kbVC410bug kbVC420bug kbVC500bug kbVC600bug 
Technology        : kbVCsearch kbAudDeveloper kbCVCComp
Version           : :1.0,1.5,2.0,4.0,4.1,4.2,5.0,6.0
Issue type        : kbbug

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

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.