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

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 v5.16.3				    2014-06-10					  RRDp(3)
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