Hi Oliver I’m afraid you’ll always need a DEF from somewhere. I’ve done plenty of workarounds like this, including having an empty rrdfile that is never updated. Usually I end up doing something like this to get just a 0 value...
DEF:foo=/some/empty/rrdfile.rrd:foo:AVERAGE CDEF:myval=foo,POP,0 Hope that helps :) Cheers, Jacques > On 14 Feb 2017, at 20:49, Olivier Doucet <[email protected]> wrote: > > Hi, > > > 2017-02-14 19:44 GMT+01:00 SolarMan <[email protected] > <mailto:[email protected]>>: > Hello Olivier, > The error message is confusing and should actually read: > rrdtool.OperationalError: rpn expressions without DEF or CDEF variables are > not supported > as it does in other cases. > The meaning is clear: you must use a DEF or CDEF in your CDEF definition. > Regards, > hans > > Thank you Hans for your quick response. I understand the documentation is > wrong then. > > Any idea how to easily create a DEF with 0 value all along ? I'm using it in > a automatized script that write the whole 'rrdtool graph' line, and when > original DEF file is not present, I would like to replace it with 0 to keep > the same logic. > > Olivier > > > _______________________________________________ > rrd-users mailing list > [email protected] > https://lists.oetiker.ch/cgi-bin/listinfo/rrd-users
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