[rrd-users] getting MAX, LAST VDEFs without generating graph from C library

[Tobias Oetiker]

Hi Jack,

check out rrd_tool.c for inspiration

cheers
tobi

Today Jack Tavares wrote:

> Hello all
>
> I have some existing rrdfile with some data in them.
>
> I was reading  about the VDEF capabilities of the rrdgraph
> command.
>
> I am using the c library functions to manipulate the rrd files.
>
> I want the MAX and LAST from a graph, but I don't want the graph.
>
> At the command line I would do:
>
> rrdtool graph xy.png -aPNG
> DEF:curclientconns=/var/rrd/connections:curclientconns:AVERAGE
> VDEF:connsmax=curclientconns,MAXIMUM VDEF:connslast=curclientconns,LAST
> PRINT:connslast:"last=%12.0lf" PRINT:connsmax:"max=%12.0lf"
>
> This prints to stdout.
>
> If I am calling rrd_graph() C function, how do I get this data?
>
>
> Is there a better way to do this? I m very open to suggestions, but I
> have to stick with the C library calls.
>
> Ok, one more question:
> I dont see any API docs for theC library on the web site. Are there any?
>
> Thanks again
>
> --
> Jack Tavares
> Reminder: I am at GMT+2, 10 hours AHEAD of Seattle.
> My workweek is Sunday-Thursday.
> Email sent to me Thursday afternoon (PST) may not be viewed until Sunday
> morning (GMT+2).
>
>
>

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