Q115705

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page	Q115705: BUG: Function Style Conversion Incorrectly Generates Errors	/kb/115/Q115705/

Q115705: BUG: Function Style Conversion Incorrectly Generates Errors

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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

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

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