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 RRDtool's 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 RRDtool's 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 $$answer which dereferences
the variable.
$status = RRDp::end terminates RRDtool and returns RRDtool's status ...
$RRDp::user,  $RRDp::sys, $RRDp::real these variables will contain totals of the user time, system time and
real time as seen by RRDtool.  User time is the time RRDtool is
running, System time is the time spend in system calls and real time
is the total time RRDtool has been running.
The difference between user + system and real is the time spent
waiting for things like the hard disk and new input from the perl
script.
EXAMPLE 
 use RRDp;
 RRDp::start "/usr/local/bin/rrdtool";
 RRDp::cmd   qw(create demo.rrd --step 100 
               DS:in:GAUGE:100:U:U
               RRA:AVERAGE:0.5:1:10);
 $answer = RRDp::read;
 print $$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 < mailto:oetiker@ee.ethz.choetiker@ee.ethz.ch >
