1RRDp(3)               User Contributed Perl Documentation              RRDp(3)
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NAME

6       RRDp - Attach RRDtool from within a perl script via a set of pipes;
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SYNOPSIS

9       use RRDp
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11       RRDp::start path to RRDtool executable
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13       RRDp::cmd  rrdtool commandline
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15       $answer = RRD::read
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17       $status = RRD::end
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19       $RRDp::user,  $RRDp::sys, $RRDp::real, $RRDp::error_mode, $RRDp::error
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DESCRIPTION

22       With this module you can safely communicate with the RRDtool.
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24       After every RRDp::cmd you have to issue an RRDp::read command to get
25       RRDtools answer to your command. The answer is returned as a pointer,
26       in order to speed things up. If the last command did not return any
27       data, RRDp::read will return an undefined variable.
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29       If you import the PERFORMANCE variables into your namespace, you can
30       access RRDtool's internal performance measurements.
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32       use RRDp
33               Load the RRDp::pipe module.
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35       RRDp::start path to RRDtool executable
36               start RRDtool. The argument must be the path to the RRDtool
37               executable
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39       RRDp::cmd rrdtool commandline
40               pass commands on to RRDtool. Check the RRDtool documentation
41               for more info on the RRDtool commands.
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43               Note: Due to design limitations, RRDp::cmd does not support the
44               "graph -" command - use "graphv -" instead.
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46       $answer = RRDp::read
47               read RRDtool's response to your command. Note that the $answer
48               variable will only contain a pointer to the returned data. The
49               reason for this is, that RRDtool can potentially return quite
50               excessive amounts of data and we don't want to copy this around
51               in memory. So when you want to access the contents of $answer
52               you have to use $$answer which dereferences the variable.
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54       $status = RRDp::end
55               terminates RRDtool and returns RRDtool's status ...
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57       $RRDp::user,  $RRDp::sys, $RRDp::real
58               these variables will contain totals of the user time, system
59               time and real time as seen by RRDtool.  User time is the time
60               RRDtool is running, System time is the time spent in system
61               calls and real time is the total time RRDtool has been running.
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63               The difference between user + system and real is the time spent
64               waiting for things like the hard disk and new input from the
65               Perl script.
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67       $RRDp::error_mode and $RRDp::error
68               If you set the variable $RRDp::error_mode to the value 'catch'
69               before you run RRDp::read a potential ERROR message will not
70               cause the program to abort but will be returned in this
71               variable. If no error occurs the variable will be empty.
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73                $RRDp::error_mode = 'catch';
74                RRDp::cmd qw(info file.rrd);
75                print $RRDp::error if $RRDp::error;
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EXAMPLE

78        use RRDp;
79        RRDp::start "/usr/local/bin/rrdtool";
80        RRDp::cmd   qw(create demo.rrd --step 100
81                      DS:in:GAUGE:100:U:U
82                      RRA:AVERAGE:0.5:1:10);
83        $answer = RRDp::read;
84        print $$answer;
85        ($usertime,$systemtime,$realtime) =  ($RRDp::user,$RRDp::sys,$RRDp::real);
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SEE ALSO

88       For more information on how to use RRDtool, check the manpages.
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AUTHOR

91       Tobias Oetiker <tobi@oetiker.ch>
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95perl v5.34.0                      2021-07-23                           RRDp(3)
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