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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 ...
         RRDs::times(start, end)

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.

       The RRDs::times function takes two parameters:  a "start" and "end"
       time.  These should be specified in the AT-STYLE TIME SPECIFICATION
       format used by rrdtool.  See the rrdfetch documentation for a detailed
       explanation on how to specify time.

   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;

   Return Values
       The functions RRDs::last, RRDs::graph, RRDs::info, RRDs::fetch and
       RRDs::times 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";
         }

       RRDs::times returns two integers which are the number of seconds since
       epoch (1970-01-01) for the supplied "start" and "end" arguments,
       respectively.

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

NOTE
       If you are manipulating the TZ variable you should also call the posixs
       function tzset to initialize all internal state of the library for
       properly operating in the timezone of your choice.

        use POSIX qw(tzset);
        $ENV{TZ} = 'CET';
        POSIX::tzset();

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

1.0.50                            2005-04-25                           RRDs(3)