display
The display
command displays the specified expression's
value each time program execution stops.
Syntax
display expression
- expression is a combination of variables, constants and operators.
Usage
The display
command allows you to add an expression to an automatic
display list. The values of the expressions in the list are printed each time program
execution stops. Each expression in the list is assigned a number to identify it.
This command is useful in tracking how the values of expressions change during the program's execution.
Example
MAIN
DEFINE x INTEGER
FOR x = 1 TO 10
DISPLAY x
END FOR
END MAIN
$ fglcomp -M prog.4gl && fglrun -d prog.42m
(fgldb) break 5
Breakpoint 1 at 0x00000000: file prog.4gl, line 5.
(fgldb) run
Breakpoint 1, main() at prog.4gl:5
2 DEFINE x INTEGER
3
4 FOR x = 1 TO 10
-> 5 DISPLAY x
6 END FOR
7
8 END MAIN
(fgldb) display x
1: x = 1
(fgldb) continue
Continuing.
1
Breakpoint 1, main() at prog.4gl:5
1: x = 2
2 DEFINE x INTEGER
3
4 FOR x = 1 TO 10
-> 5 DISPLAY x
6 END FOR
7
8 END MAIN
(fgldb) continue
Continuing.
2
Breakpoint 1, main() at prog.4gl:5
1: x = 3
2 DEFINE x INTEGER
3
4 FOR x = 1 TO 10
-> 5 DISPLAY x
6 END FOR
7
8 END MAIN