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Craig DeForest > Alien-Gnuplot > Alien::Gnuplot



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Module Version: 1.033   Source  


Alien::Gnuplot is intended for distribution via CPAN. This repository stores the history for the Alien::Gnuplot module on CPAN. Install the module via CPAN.


Alien::Gnuplot - Find and verify functionality of the gnuplot executable.


 package MyGnuplotter;

 use strict;

 use Alien::Gnuplot;

 $gnuplot = $Alien::Gnuplot::executable;

 `$gnuplot < /tmp/plotfile`;



Alien::Gnuplot verifies existence and sanity of the gnuplot external application. It only declares one access method, Alien::Gnuplot::load_gnuplot, which does the actual work and is called automatically at load time. Alien::Gnuplot doesn't have any actual plotting methods - making use of gnuplot, once it is found and verified, is up to you or your client module.

Using Alien::Gnuplot checks for existence of the executable, verifies that it runs properly, and sets several global variables to describe the properties of the gnuplot it found:

You can point Alien::Gnuplot to a particular path for gnuplot, by setting the environment variable GNUPLOT_BINARY to the path. Otherwise your path will be searched (using File::Spec) for the executable file.

If there is no executable application in your path or in the location pointed to by GNUPLOT_BINARY, then the module throws an exception. You can also verify that it has not completed successfully, by examining $Alien::Gnuplot::version, which is undefined in case of failure and contains the gnuplot version string on success.

If you think the global state of the gnuplot executable may have changed, you can either reload the module or explicitly call Alien::Gnuplot::load_gnuplot() to force a fresh inspection of the executable.


When you install Alien::Gnuplot, it checks that gnuplot itself is installed as well. If it is not, then Alien::Gnuplot attempts to use one of several common package managers to install gnuplot for you. If it can't find one of those, if dies (and refuses to install), printing a friendly message about how to get gnuplot before throwing an error.

In principle, gnuplot could be automagically downloaded and built, but it is distributed via Sourceforge -- which obfuscates interior links, making such tools surprisingly difficult to write.


On POSIX systems, including Linux and MacOS, Alien::Gnuplot uses fork/exec to invoke the gnuplot executable and asynchronously monitor it for hangs. Microsoft Windows process control is more difficult, so if $^O contains "MSWin32", a simpler system call is used, that is riskier -- it involves waiting for the unknown executable to complete.


Gnuplot's main home page is at

Alien::Gnuplot development is at

A major client module for Alien::Gnuplot is PDL::Graphics::Gnuplot, which can be found at PDL is at


Craig DeForest <>

(with special thanks to Chris Marshall, Juergen Mueck, and Sisyphus for testing and debugging on the Microsoft platform)


Copyright (C) 2013 Craig DeForest

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

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