INFO: Cannot Define Other Preprocessor Directives with #define

• The Microsoft C/C++ Compiler (CL.EXE) included with: - Microsoft C for MS-DOS, versions 6.0, 6.0a, 6.0ax - Microsoft C for OS/2, versions 6.0, 6.0a - Microsoft C/C++ for MS-DOS, version 7.0 - Microsoft Visual C++ for Windows, versions 1.0, 1.5 - Microsoft Visual C++ 32-bit Edition, versions 1.0, 2.0, 4.0, 5.0

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'

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

            error C2121: '#' : invalid character : possibly the result of a

            error C2282: 'define' is followed by 'MAX' (missing ','?)

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 ];
   }