rrdtool is called via the RRDp module from your rrdtool-perl package.
use RRDp;
# start RRD via a pipe
RRDp::start "$rrdtool";
timing_debug("rrdtool start");
# keep here green - yellow - red - blue ...
my @color = ( "#FF0000", "#0000FF", "#FFFF00", "#00FFFF", "#FFA500", "#00FF00", "#808080", "#FF00FF", "#800080", "#FDD017", "#0000A0", "#3BB9FF", "#008000", "#800000",
"#C0C0C0", "#ADD8E6", "#F778A1", "#800517", "#736F6E", "#F52887", "#C11B17", "#5CB3FF", "#A52A2A", "#FF8040", "#2B60DE", "#736AFF", "#1589FF", "#98AFC7", "#8D38C9", "#3
07D7E", "#F6358A", "#151B54", "#6D7B8D", "#FDEEF4", "#FF0080", "#F88017", "#2554C7", "#FFF8C6", "#D4A017", "#306EFF", "#151B8D", "#9E7BFF", "#EAC117", "#E0FFFF", "#1531
7E", "#6C2DC7", "#FBB917", "#FCDFFF", "#15317E", "#254117", "#FAAFBE", "#357EC7", "#4AA02C", "#38ACEC" );
my $color_max = 53; # 0 - 53 is 54 colors
my @table_out = "";
my $ret = create_graph( $host, $server, $lpar, $item, $time, $name_out, $type_sam, $upper, $alarm, $graph_hours, $amax, $start_unix, $end_unix, $entitle );
# close RRD pipe
RRDp::end;