QuickBasic - Error handling inside function

[SlowCoder]

It's been about ... forever ... since I've worked in QB. I Thought, for nostalgic reasons, I'd get back to playing with it and write something that *someone* might find useful.

Anyway, here's the issue ...

I've got the following function, which returns the highest number of rows available in the current resolution:

FUNCTION HighScreenRows
   DIM ScreenMode(4)
   '*** find maximum screen rows ***
   ScreenMode(1) = 25: ScreenMode(2) = 43: ScreenMode(3) = 50: ScreenMode(4) = 60
   FOR intRows = 1 TO 4
      ResolutionGood = 1
      ON ERROR GOTO ErrorHandler
      WIDTH 80, ScreenMode(intRows)
      ON ERROR GOTO 0
      '
      IF ResolutionGood = 1 THEN HighScreenRows = ScreenMode(intRows)
   NEXT intRows
   '
   VIEW PRINT
   EXIT FUNCTION

ErrorHandler:
   '*** capture screenmode errors ***
   ResolutionGood = 0
   RESUME NEXT

END FUNCTION

The code relies on the error handling to determine rows. The problem is that it gives me a "Label not found" on the "ON ERROR GOTO ErrorHandler" line.

Any help here?

[Peter Swinkels]

Labels pointed to by the ON ERROR statement should not be inside a procedure (SUB/FUNCTION), but globally available.

I'm not sure whether this properly answers your question, but:
To get the resolution of a specific graphics mode, the POINT() function can be used as follows:

SCREEN 12 'Sets a graphics mode.
VIEW 'Resets the graphics cursor without erasing the screen.
PRINT POINT(0) * 2 'The horizontal resolution.
PRINT POINT(1) * 2 The vertical resolution.

The above code uses the graphics cursor's initial position to calculate the screen resolution.

And for determining the number of available text rows:

SCREEN 0: CLS : WIDTH 80, 43
DIM Row AS LONG
ON ERROR GOTO ReachedLastRow
Row = 1
DO
   LOCATE Row
   Row = Row + 1
LOOP
EndOfRoutine:
ON ERROR GOTO 0
END

ReachedLastRow:
LOCATE 1, 1
PRINT "Number of rows available in the current screen mode: "; Row - 1
RESUME EndOfRoutine

(And yes, I've noticed this post is 2 years old.)