QB.EXE 4.x Won't Trace or Single Step through KEY Routine (40631)

MORE INFORMATION

This article applies to all forms of ON Event GOSUB, where the Event can be COM(n), KEY(n), PEN, PLAY(q), STRIG(n), and TIMER(n).

To trace through a program in QuickBasic Versions 4.x, choose the Debug menu, toggle the Trace On option, and run the program. (In QuickBasic Version 3.00, insert the statement TRON as the first statement of the program and run it.)

To Single Step through a program in QuickBasic Versions 4.x, press F8 repeatedly. (In QuickBasic Version 3.00, you need to choose DEBUG from the Run menu, then press F8 repeatedly.)

When you single step or trace the program below in the QuickBasic Versions 4.00, 4.00b, and 4.50 editors, press F1 or F2 while the program is waiting for INPUT activates the key-trapping routine. After you press ENTER to terminate the INPUT, the editor executes the key-trapping routine but does not display the single stepping or tracing.

To work around this behavior, set a breakpoint at the label of the key-handling routine to stop execution at the label. Then, the QB.EXE editor correctly single steps or traces through the key routine. You can press F5 to continue tracing or press F8 for single stepping.

The following is a code example:

ON KEY(1) GOSUB KeyRoutine1
ON KEY(2) GOSUB KeyRoutine2
KEY(1) ON
KEY(2) ON
WHILE 1
INPUT "Press F1 or F2 and then hit ENTER key", X$
WEND
END
KeyRoutine1: 'Must set a breakpoint here to single step
                   'or trace through this routine.
   PRINT "inside key routine 1"
   RETURN
KeyRoutine2: 'Must set a breakpoint here to single step
                   'or trace through this routine.
   PRINT "inside key routine 2"
   RETURN