Preventing Infinite Loops (Basic Syntax) in Crystal Report

There is a safety mechanism to prevent report processing from hanging due to an infinite loop. Any one evaluation of a formula can have at most 100,000 loop condition evaluations per formula evaluation. For example:

Dim i

i = 1

Do While i <= 200000

   If i > {movie.STARS} Then Exit Do

   i = i + 1

Loop

formula = 20

If {movie.STARS} is greater than 100,000 then the loop condition (i <= 200000) will be evaluated more than the maximum number of times and an error message is displayed. Otherwise the loop is OK.

Note   The safety mechanism applies on a per formula base, not for each individual loop. For example:

Dim i

i = 1

For i = 1 To 40000

   formula = Sin (i)

Next i

Do While i <= 70000

   i = i + 1

Loop

The above formula also triggers the safety mechanism since the 100,000 refers to the total number of loop condition evaluations in the formula and this formula will have 40001 + 70001 such evaluations.