I am working with dates and seconds and coming up with a “Instant Date” based on a formula provided to me. I have reversed that formula and written it out in my desktop app to convert dates to their “Instant Date”.
I have tested this in a standalone app and it works great. The problem is when I move this in to the actual app that it needs to work in, the final value is changing.
Here is the code I am using (I’m iterating through a sql database and putting the values in to a listbox):
dim dateline as String = row.column("Date").StringValue //THE TEST DATE IS 07/25/18
dim year as string = "20" + dateline.Right(2) //CONFIRMED OUTPUT: 2018
dim month as integer = dateline.Left(2).ToInteger //CONFIRMED OUTPUT: 07
dim day as Integer = dateline.Middle(3,2).ToInteger //CONFIRMED OUTPUT: 25
dim dcheck as new DateTime(year.ToInteger,month,day) //CONFIRMED DATE IS ACCURATE
dim past as new DateTime(1900,1,1)
//THIS OUTPUTS A VALUE OF 43306 (WHICH IS WHAT IT SHOULD BE)
dim calc as Integer = ((dcheck.SecondsFrom1970 - past.SecondsFrom1970)/86400)+2
//THIS SHOULD OUTPUT 5603385600 BUT IT OUTPUTS 1308418304
// (43306+21548)*86400 = 5603385600
dim calc2 as Integer = (calc+21548)*86400
//OUTPUT values to Listbox for troubleshooting
Main.EXDBLoad.Cell(Main.EXDBLoad.LastIndex, 8) = calc.ToString + " - " + calc2.ToString
What would cause calc2 to output a completely different number?
Yeah it’s odd. On a Mac its off by 1. I actually have that +2 at the end as a text box so it can be updated. Im not sure what causes it as of right now, but once I figure it out I will put in a more long term solution.
I think it might have to do with timezones but I haven’t been able to consistently prove that yet.
It may be possible that Xojo have a code base with possible multiple points of failure, like a math lib for Windows, another one for Mac, another for Linux, etc so when they touch one place and forget the equivalent in another platform, inconsistencies are introduced.
dim dateline as String = "07/25/18" //THE TEST DATE IS 07/25/18
dim year as string = "20" + dateline.Right(2) //CONFIRMED OUTPUT: 2018
dim month as integer = dateline.Left(2).ToInteger //CONFIRMED OUTPUT: 07
dim day as Integer = dateline.Middle(3,2).ToInteger //CONFIRMED OUTPUT: 25
dim dcheck as new DateTime(year.ToInteger,month,day) //CONFIRMED DATE IS ACCURATE
dim past as new DateTime(1900,1,1)
//THIS OUTPUTS A VALUE OF 43306 (WHICH IS WHAT IT SHOULD BE)
dim calc as Integer = ((dcheck.SecondsFrom1970 - past.SecondsFrom1970)/86400)+2
//calc = 43305 or 43306?
//THIS SHOULD OUTPUT 5603385600 BUT IT OUTPUTS 1308418304
// (43306+21548)*86400 = 5603385600
dim calc2 as Integer = (calc+21548)*86400
I have ran it on 4 different machines and 3/4 give me 43305 and the 4th which is on a Frame VM gives me 43306. Because of this in my GUI I have a text field that allows me to change that +2 to whatever number I need to get the expected outcome. This is why I think, somehow, this is related to timezones and that VM is forcing it to not UTC. But I am unsure exactly.
