


RRDs(3)                      rrdtool                      RRDs(3)


NAME
       RRDs - Access rrdtool as a shared module

SYNOPSIS
         use RRDs;
         RRDs::error
         RRDs::last ...
         RRDs::info ...
         RRDs::create ...
         RRDs::update ...
         RRDs::graph ...
         RRDs::fetch ...
         RRDs::tune ...


DESCRIPTION
       Calling Sequence

       This module accesses rrdtool functionality directly from
       within perl. The arguments to the functions listed in the
       SYNOPSIS are explained in the regular rrdtool
       documentation. The commandline call

        rrdtool update mydemo.rrd --template in:out N:12:13

       gets turned into

        RRDs::update ("mydemo.rrd", "--template", "in:out", "N:12:13");

       Note that

        --template=in:out

       is also valid.

       Error Handling

       The RRD functions will not abort your program even when
       they can not make sense out of the arguments you fed them.

       The function RRDs::error should be called to get the error
       status after each function call. If RRDs::error does not
       return anything then the previous function has completed
       its task successfully.

        use RRDs;
        RRDs::update ("mydemo.rrd","N:12:13");
        my $ERR=RRDs::error;
        die "ERROR while updating mydemo.rrd: $ERR\n" if $ERR;








2002-05-22                    1.0.38                            1





RRDs(3)                      rrdtool                      RRDs(3)


       Return Values

       The functions RRDs::last, RRDs::graph, RRDs::info and
       RRDs::fetch return their findings.

       RRDs::last returns a single INTEGER representing the last
       update time.

        $lastupdate = RRDs::last ...

       RRDs::graph returns an pointer to an ARRAY containing the
       x-size and y-size of the created gif and results of the
       PRINT arguments.

        ($averages,$xsize,$ysize) = RRDs::graph ...
        print "Gifsize: ${xsize}x${ysize}\n";
        print "Averages: ", (join ", ", @$averages);

       RRDs::info returns a pointer to a hash. The keys of the
       hash represent the property names of the rrd and the
       values of the hash are the values of the properties.

        $hash = RRDs::info "example.rrd";
        foreach my $key (keys %$hash){
          print "$key = $$hash{$key}\n";
        }

       RRDs::fetch is the most complex of the pack regarding
       return values. There are 4 values. Two normal integers, a
       pointer to an array and a pointer to a array of pointers.

         my ($start,$step,$names,$data) = RRDs::fetch ...
         print "Start:       ", scalar localtime($start), " ($start)\n";
         print "Step size:   $step seconds\n";
         print "DS names:    ", join (", ", @$names)."\n";
         print "Data points: ", $#$data + 1, "\n";
         print "Data:\n";
         foreach my $line (@$data) {
           print "  ", scalar localtime($start), " ($start) ";
           $start += $step;
           foreach my $val (@$line) {
             printf "%12.1f ", $val;
           }
           print "\n";
         }

       See the examples directory for more ways to use this
       extension.

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






2002-05-22                    1.0.38                            2


