[Gambas-user] Overflow Errors with Gambas 3.18 and Master

Claus Dietrich claus.dietrich at freenet.de
Sat Jan 14 22:39:58 CET 2023

Am 14.01.23 um 19:14 schrieb Benoit Minisini:
> Yes, but the computation overflows. This was ignored by Gambas 3.17.3, 
> and is now detected by Gambas 3.18.0.
> The fact that the overflow leads to the expected result relies on an 
> implicit behaviour of the underlying CPU. But the C standard 
> explicitly says that arithmetic overflow lead to unspecified results. 
> In other words, this is an error to write code that relies on that 
> specific CPU behaviour.
> In practice, it's not a big deal, as the only CPUs I'm aware of where 
> oveflow does not always behave the "expected" way are Cray Computer CPUs.
> Anyway, to let your old project run as before, there is now a 
> 'System.IgnoreOverflow' property that restores the old behaviour. Just 
> set this property to TRUE at the beginning of your program.
> Regards, 

Thanks a lot for this exhaustive explanation. Your suggested 
modification on the code works perfectly.

Am 13.01.23 um 22:29 schrieb Benoit Minisini:
> Le 13/01/2023 à 22:13, Claus Dietrich a écrit :
>> This morning I received an email from a friend with a screenshot of 
>> an error message which occurred in his Gambas IDE after he upgraded 
>> to 3.18:
>> This application has raised an unexpected error and must abort
>> [7] Overflow
>> [gb.form.editor].CDocument.HighlightLine.935
>> He seems to run the IDE under QT5.
> This is a bug to fix. 

On behalf of Hans: Is someone taking care of it? Anything required from 
Hans? Shall I report it in the bugtracker?

Best regards


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