Q38291: INFO: Cannot Define Other Preprocessor Directives with #define

Article: Q38291
Product(s): Microsoft C Compiler
Version(s): 1.0,1.5,2.0,4.0,5.0,6.0,7.0
Operating System(s): 
Keyword(s): kbCompiler kbVC100 kbVC150 kbVC200 kbVC400 kbVC500 kbVC600
Last Modified: 25-JUL-2001

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The information in this article applies to:

- Microsoft C/C++ Compiler (CL.EXE), used with:
   - Microsoft C/C++ for MS-DOS, version 7.0 
   - Microsoft C for MS-DOS 
   - Microsoft C for OS/2 
   - 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 
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SUMMARY
=======

The Microsoft C Compiler does not allow a "#define" statement to define another
preprocessor directive. Although the preprocessor output option (/P or /E)
generates the desired expansion, the Microsoft C Compiler generates the
following error messages when compiling the code below:

  error C2014: preprocessor command must start as first non-whitespace
  error C2054: expected '(' to follow 'define'
  error C2061: syntax error : identifier 'MAX'

Microsoft C/C++ for Windows NT, version 8.0, generates the following errors on
the code shown below:

  error C2014: preprocessor command must start as first nonwhite space
  error C2065: 'MAX' : undeclared identifier
  error C2057: expected constant expression

The Microsoft C/C++ compiler included with Visual C++, 32-bit edition, version
4.0, generates the following errors on the code shown below:

  error C2121: '#' : invalid character : possibly the result of a macro
  expansion
  error C2282: 'define' is followed by 'MAX' (missing ','?)

The Microsoft C/C++ compiler included with Visual C++, 32-bit edition, versions
5.0 and 6.0, generates the following errors on the code shown below:

  error C2121: '#' : invalid character : possibly the result of a macro
  expansion
  error C2146: syntax error : missing ';' before identifier 'MAX'
  error C2501: 'define' : missing storage-class or type specifiers
  fatal error C1004: unexpected end of file found

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

The following code demonstrates the problem:

  /* Compile options needed: none
  */ 

  #define A( x )      x##define       MAX     100

  A( # )
  /*
      Preprocessor output expands A( # ) to be:
  #define       MAX     100
  */ 

  char w[ MAX ];
  void main(void);
  void main()
  {
     w[ 0 ] = w[ MAX ];
  }

Additional query words: 8.00 8.00c 9.00

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Keywords          : kbCompiler kbVC100 kbVC150 kbVC200 kbVC400 kbVC500 kbVC600 
Technology        : kbVCsearch kbAudDeveloper kbCVCComp
Version           : :1.0,1.5,2.0,4.0,5.0,6.0,7.0
Issue type        : kbinfo

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