Last couple of days I was trying to pinpoint a bug a user reported… In the first place I really could not find why this bug was happening. I tried about anything but the maths did not make any sense. In the end I did found why the bug pops up in some occasions. I could make a simplified example to…

It’s not negative. It’s 10000000000000000000 the first time and multiplied by 2 every other time. And why does it work correct when multiplying with even values and not with uneven? There is definitely something wrong with Xojo math or the IF…THEN procedure. EDIT: changing to UINT64 does also not…

Dim timeNano1 as int64 timeNano1= 10000000000000000000 for a as integer = 1 to 10 if (timeNano1*a) > CType(0, Int64) then msgbox "Is bigger than zero @ a="+str(a) end next a Try the above This is compile comparison error cause you have Int64, Integer and comparing to Integer i get output: …

[image] ChristopheDV: Dim timeNano1 as int64 timeNano1= 10000000000000000000 If I put a breakpoint after the second line, the debugger shows -8446744073709551616. The largest number you can store in an Int64 is 9223372036854775807. 10000000000000000000 is larger than 9223372036854775807.

Try with UINT64 … that can hold higher values but the issue remains.

@ DerkJ Bummer … that does fix the issue. But why do I need use CType(0, Int64) and why does plain ‘0’ does not work? This smells like a Xojo problem to me.

I did search the forum I am apparently not alone with this problem. This thread tells me it IS a Xojo problem - likely a compiler problem. [image] Something funky about UInt32 comparisons General Nobody has shown even one example of how fixing this comparison will have a …

It does NOT fix it. Since @kevin_g is right, it’s coming out negative. -8446744073709551616 - NOT bigger than zero @ a=1 1553255926290448384 - Is bigger than zero @ a=2 -6893488147419103232 - NOT bigger than zero @ a=3 3106511852580896768 - Is bigger than zero @ a=4 …

It seems to be a compiler issue. [image] Something funky about UInt32 comparisons General As Geoff said multiple times, this behavior is 10+ years old and by design. It looks like there is now a feature request for this. If it is important to you please see the case: https…

use CType to work around it if you can. If i use only Uint64 i get this output: 10000000000000000000 - Is bigger than zero @ a=1 1553255926290448384 - Is bigger than zero @ a=2 11553255926290448384 - Is bigger than zero @ a=3 3106511852580896768 - Is bigger than zero @ a=4 13106511852580896768…

[image] ChristopheDV: Dim timeNano1 as int64 timeNano1= 10000000000000000000 for a as integer = 1 to 10 if (timeNano1*a) > 0 then msgbox "Is bigger than zero @ a="+str(a) end next a I do see some kind of bug when timeNano1 is UInt64. I suggest you log it in Feedback.

Very odd math mismatch when using IF...THEN

General

ChristopheDV (ChristopheDV) November 5, 2020, 9:36am 8

I did search the forum I am apparently not alone with this problem.
This thread tells me it IS a Xojo problem - likely a compiler problem.