Alien::Gnuplot - Find and verify functionality of the gnuplot executable.
$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:
gets the path to the gnuplot executable.
gets the self-reported version number of the executable.
gets the self-reported patch level.
gets a list of the names of all supported terminal devices.
gets a key for each supported terminal device; values are the 1-line
description from gnuplot. This is useful for testing whether a particular
terminal is supported.
gets a list of the names of all named colors recognized by this
gets a key for each named color; values are the "#RRGGBB" form of
the color. This is useful for decoding colors, or for checking whether a
particular color name is recognized. All the color names are lowercase
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
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
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 <http://www.gnuplot.info>.
Alien::Gnuplot development is at
A major client module for Alien::Gnuplot is PDL::Graphics::Gnuplot, which can be
found at <http://github.com/drzowie/PDL-Graphics-Gnuplot>. PDL is at
Craig DeForest <email@example.com>
(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.