


RRDp(3)                      rrdtool                      RRDp(3)


NAME
       RRDp - Attach rrdtool from within a perl script via a set
       of pipes;

SYNOPSIS
       use RRDp

       RRDp::start path to rrdtool executable

       RRDp::cmd  rrdtool commandline

       $answer = RRD::read

       $status = RRD::end

       $RRDp::user,  $RRDp::sys, $RRDp::real

DESCRIPTION
       With this module you can safely communicate with the
       rrdtool.

       After every RRDp::cmd you have to issue an RRDp::read
       command to get rrdtools answer to your command. The answer
       is returned as a pointer, in order to speed things up. If
       the last command did not return any data, RRDp::read will
       return an undefined variable.

       If you import the PERFORMANCE variables into your
       namespace, you can access rrdtools internal performance
       measurements.

       use RRDp
               Load the RRDp::pipe module.

       RRDp::start path to rrdtool executable
               start rrdtool. The argument must be the path to
               the rrdtool executable

       RRDp::cmd rrdtool commandline
               pass commands on to rrdtool. check the rrdtool
               documentation for more info on the rrdtool
               commands.

       $answer = RRDp::read
               read rrdtools response to your command. Note that
               the $answer variable will only contain a pointer
               to the returned data. The reason for this is, that
               rrdtool can potentially return quite excessive
               amounts of data and we don't want to copy this
               around in memory. So when you want to access the
               contents of $answer you have to use $$answer which
               dereferences the variable.





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RRDp(3)                      rrdtool                      RRDp(3)


       $status = RRDp::end
               terminates rrdtool and returns rrdtools status ...

       $RRDp::user,  $RRDp::sys, $RRDp::real
               these variables will contain totals of the user
               time, system time and real time as seen by
               rrdtool.  User time is the time rrdtool is
               running, System time is the time spend in system
               calls and real time is the total time rrdtool has
               been running.

               The difference between user + system and real is
               the time spent waiting for things like the hard
               disk and new input from the perl script.

EXAMPLE
        use RRDp;
        RRDp::start "/usr/local/bin/rrdtool";
        RRDp::cmd   qw(create demo.rrd --step 100
                      DS:in:GAUGE:100:U:U
                      RRA:AVERAGE:0.5:1:10);
        $answer = RRDp::read;
        print $$answer;
        ($usertime,$systemtime,$realtime) =  ($RRDp::user,$RRDp::sys,$RRDp::real);


SEE ALSO
       For more information on how to use rrdtool, check the
       manpages.

AUTHOR
       Tobias Oetiker <oetiker@ee.ethz.ch>

























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