INCLUDE Preprocessor Directive Example

In the following example, two files are used: Const.h, a header file, and Myprog.prg, a program file. The header file contains several #DEFINE directives that create compile-time constants. The program file uses #INCLUDE to merge the Const.h header file at compilation, making the compile-time constants in the header file available to the program.

*** Header file CONST.H ***
#DEFINE ERROR_NODISK     1
#DEFINE ERROR_DISKFULL  2
#DEFINE ERROR_UNKNOWN  3

*** Program file MYPROG.PRG ***
#INCLUDE CONST.H

FUNCTION chkerror
PARAMETER errcode
  DO CASE
  CASE errcode = ERROR_NODISK
  ?"Error - No Disk"
  CASE errcode = ERROR_DISKFULL
  ?"Error - Disk Full"
  CASE errcode = ERROR_UNKNOWN
  ?"Unknown Error"
  ENDCASE
RETURN