Example 1: Multiple GLOBALS file

Important:

Defining global variables in a GLOBALS block is deprecated. Instead of GLOBALS, use PUBLIC symbols in modules to be imported with IMPORT FGL. GLOBALS is only supported for backward compatibility, to compile legacy source code.

Why not globals? Global variables visible and modifiable across the entire program code is an old concept that reduces modularity and flexibility. GLOBALS implements specific semantics that restrain source code organization; for example, it is allowed to specify a file path such as GLOBALS "../../common/myglobals.4gl". The globals file can define functions after the GLOBALS block that are ignored when including such file.

Conversely, the IMPORT FGL instruction brings more flexibility and allows a better organization of your source code, by grouping public variables in modules where other symbols (functions, types, contants) belong to the same domain.

Module "labels.4gl": This module defines the text that is displayed on the screen

GLOBALS
  CONSTANT g_lbl_val = "Index:"
  CONSTANT g_lbl_idx = "Value:"
END GLOBALS

Module "globals.4gl": Declares a global array and a constant containing its size

GLOBALS "labels.4gl" -- this statement could be line 2 of main.4gl

GLOBALS
  DEFINE g_idx ARRAY[100] OF CHAR(10)
  CONSTANT g_idxsize = 100
END GLOBALS

Module "database.4gl": This module is dedicated to database access

GLOBALS "globals.4gl"

FUNCTION get_id()
  DEFINE li INTEGER
  FOR li = 1 TO g_idxsize -- this could be a FOREACH statement 
      LET g_idx[li] = g_idxsize - li 
  END FOR
END FUNCTION

Module "main.4gl": Fill in the global array and display the result

GLOBALS "globals.4gl"

MAIN
  DISPLAY "Initializing constant values for this application..."
  DISPLAY "Filling the data from function get_idx in module database.4gl..."
  CALL get_id()
  DISPLAY "Retrieving a few values from g_idx"
  CALL display_data()
END MAIN

FUNCTION display_data()
  DEFINE li INTEGER
  LET li = 1
  WHILE li <= 10 AND li <= g_idxsize 
      DISPLAY g_lbl_idx CLIPPED || li || " " || g_lbl_val CLIPPED || g_idx[li]
      LET li = li + 1
  END WHILE
END FUNCTION