RRDp(3pm)						User Contributed Perl Documentation						 RRDp(3pm)

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, $RRDp::error_mode, $RRDp::error

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.

	       Note: Due to design limitations, RRDp::cmd does not support the "graph -" command - use "graphv -" instead.

       $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.

       $RRDp::error_mode and $RRDp::error
	       If you set the variable $RRDp::error_mode to the value 'catch' before you run RRDp::read a potential ERROR message will not cause
	       the program to abort but will be returned in this variable. If no error occurs the variable will be empty.

		$RRDp::error_mode = 'catch';
		RRDp::cmd qw(info file.rrd);
		print $RRDp::error if $RRDp::error;

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 <tobi@oetiker.ch>

perl v5.14.2							    2012-01-24								 RRDp(3pm)