[rrd-developers] COUNTER values must be integer? And a locale issue

[Tobias Oetiker]

Hi Henrick,

> I noticed this when looking into a problem one of my Hobbit users
> reported today. It seems that when you define a DS as a COUNTER,
> then it will only accept updates with integer values - except for
> the first time:
>
> $ rrdtool create foo.rrd DS:virt:COUNTER:600:0:U RRA:AVERAGE:0.5:1:600
> $ rrdtool update foo.rrd N:10.5
> $ rrdtool update foo.rrd N:10.5
> ERROR: not a simple integer: '10.5'
>
> It kind of makes sense that a counter must be an integer, but why does
> the first update work ok ?

you are right ... the check in the code only kicked in when the
previous update was ! U ...

r1171 has the fix ...

>
> In comparison, GAUGE datasets work fine (of course):
> $ rrdtool create bar.rrd DS:virt:GAUGE:600:0:U RRA:AVERAGE:0.5:1:600
> $ rrdtool update bar.rrd N:10.5
> $ rrdtool update bar.rrd N:10.5
> $ rrdtool update bar.rrd N:10.5
>
>
> On a slightly related note, is there any way you can ask rrdtool
> to treat both dot and comma as decimal separators ?
>
> $ rrdtool update bar.rrd N:10,5
> ERROR: conversion of '10,5' to float not complete: tail ',5'
>
> Comma is the decimal separator in some locales (e.g. danish), so
> "10,5" should be valid.
>
> hobbit$ export LANG=da_DK
> hobbit$ rrdtool update bar.rrd N:10,5
> ERROR: conversion of '10,5' to float not complete: tail ',5'
> $ printf '%f\n' 10.5
> -bash: printf: 10.5: invalid number
> 0,000000
> $ printf '%f\n' 10,5
> 10,500000

the problem is that useing , as a decimal separator will lead to
problems with RPN syntax ... so what I did for 1.3 is that I make
sure we are always in LC_NUMERIC C when doing scanf for floats ...

the reasoning behind this is that in a C or Java program you also
have to write your numbers with . ...

cheers
tobi

> Regards,
> Henrik
>
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-- 
Tobi Oetiker, OETIKER+PARTNER AG, Aarweg 15 CH-4600 Olten
http://it.oetiker.ch tobi at oetiker.ch ++41 62 213 9902