And if we ignore the nature of the error, the solution is the same:

Instead of
> cString = cString + RECURSIVE(nLevel + 1)

use

c1 = RECURSIVE(nLevel + 1)
cString = cString + c1



> Here is a much shorter program which has the same behaviour. Try to alter the values of gnMaxLevel and gnReplicate. There seems to be a trade-off between them. If gnMaxLevel is higher, gnReplicate can be lower to show a failure.
>
> If you alter the line
>
>

> cString = cString + RECURSIVE(nLevel + 1)
> 

>
> into
>
>

> cString = "" + cString + RECURSIVE(nLevel + 1)
> 

>
> or
>
>

> cString = RECURSIVE(nLevel + 1) + cString
> 

>
> no failure occurs.
>
> Benno.
>
>
>

> PUBLIC gnMaxLevel, gnReplicate
> gnMaxLevel = 6
> gnReplicate = 4
> 
> RECURSIVE(0)
> 
> FUNCTION RECURSIVE()
> 	LPARAMETERS nLevel
> 	LOCAL nLen1, nLen2, cString, cTest, cTest2
> 	
> 	IF nLevel < gnMaxLevel
> 		cString = REPLICATE("+", gnReplicate * 2 ^ (gnMaxLevel - nLevel - 1))
> 
> 		nLen1 = LEN(cString)
> 		cString = cString + RECURSIVE(nLevel + 1)
> 		nLen2 = LEN(cString)
> 		
> 		IF nLen2 < nLen1
> 			? "Failure at level: ", nLevel
> 		ELSE
> 			? "OK at level: ", nLevel
> 		ENDIF
> 	ELSE
> 		cString = REPLICATE("-", gnReplicate)
> 	ENDIF	
> 	
> 	RETURN cString
> ENDFUNC
>