StephenWonfor

How to blow up FMP 12 by totally inappropriate use of 2^n

Discussion created by StephenWonfor on Nov 22, 2012

Hi

 

This is on a Macbook Pro 8GB Ram, 2.5 Ghz i7.

 

I wrote a rather fun little script whose purpose was to stuff data into two variables ($$Picklist and $$Sublist) - at most 50 values into each. A stack of 5 digits numbers into one and a stack of single letters into the other.

Then a loop to join them together into a single variable eg.

89977 (A)

98756 (F)...

Set Variable [ $Values; Value:ValueCount($$PickList) ] Set Variable [ $Count; Value:1 ]
Loop
Set Variable [ $$MergeList; Value:

Let( [
x = $$MergeList;
y = GetValue($$Picklist; $Count);

z = GetValue($$Sublist; $Count) ];
Case(
not IsEmpty($$MergeList); $$MergeList & "¶") & x & "(" & y & ")"
)]


Set Variable [ $Count; Value:1 + $Count ]

Exit Loop If [ $Count > $Values ]
End Loop

The key part being the & x & "(" & y & ")" where I in fact was shoving $$Mergelist into itself. Should have been & y & "(" & z & ")". $Values in this case = 31, and every single time I ran the script FMPA12.0v3 would crash. Didn't matter if the file was local or hosted.

Seems I was doing an inadvertent powers of 2 test. Watching in the script debugger I noticed that $$MergeLlist was not acting as planned. The file crashes on the 23rd ( 2^23) iteration when $$Mergelist has around 210 million rows in it. As soon as the next loop starts Filemaker unexpectedly quits. Although, to be honest, after my sleuthing I find it rather "expected".

I guess variables have their limits. Likely the same 1,000,000,000 characters that a field is allowed to have. 200 million x ~10 seems about right for that.

I guess now I can re-enable all my plugins...;-)

 

Stephen

 

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"Error: The operation completed successfully. Fatal error code 0: No error."

 

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