#ifndef

Preprocessor conditional directive

Syntax
   #ifndef symbol
      ' Conditionally included statements
   #endif

Description
   Conditionally includes statements at compile time.

   Statements within the #ifndef...#endif block are included if symbol is 
   not defined and excluded (ignored) if symbol is defined.

   #ifndef symbol is equivalent to #if Not defined(symbol)

Example
   #ifndef __MYFILE_BI__
   #define __MYFILE_BI__
      ' Declarations 
   #endif

Differences from QB
   * New to FreeBASIC

See also
   * #define
   * #macro
   * #if
   * #else 
   * #elseif 
   * #endif 
   * #ifdef
   * #undef
   * defined

