[Plplot-devel] Current limitations of epa_build

[Alan W. I. <ir...@be...>]

Just to remind all of you, the fundamental purpose of epa_build on all
platforms is to first build all the PLplot dependencies (especially
useful on Windows, but also useful on Linux and Mac OS X), and then
finally build and comprehensively test PLplot in a standard way to
check for any PLplot regressions that might have been introduced
during a release cycle, check PLplot against the latest versions of
its dependencies, etc.

Andrew Ross and I have had good success with epa_build on Linux, and I
have also recently had complete success with the plplot_lite variant
of PLplot (i.e., with octave, wxwidgets, pango/cairo, and qt4_lite
dependencies dropped) on Windows (MinGW/MSYS/Wine).  But there are
still some epa_build limitations which I list below.  (I am working on
the first two of these as part of my current agenda, but all the rest
are up for grabs.)

* The wxwidgets epa_build configuration is fine on the Windows side of
things but still a work in progress on the Unix side because I haven't
figured out exactly which subset of the GTK stack of libraries needs
to be built to satisfy the Unix side dependency of wxwidgets on GTK.
On the Unix side I have so far only configured epa_builds of the
pango/cairo subset of GTK which is needed by our cairo device driver.
Adding epa_build configurations for a larger subset of the GTK
packages should be essentially trivial based on the known jhbuild data
for all GTK packages.  (See cmake/epa_build/README.developers for the
details of how jhbuild configurations are transformed to epa_build
configurations.) But I don't want to create a epa_build configuration
for every software package in the GTK stack of packages if that is not
required to satisfy the wxwidgets Unix dependencies on GTK so I am
working on this question by following the trail of Debian dependencies
of wxwidgets and hopefully I will be able to get this issue completely
sorted out in the next few days.

* The qt5_lite epa_build configuration is planned which would enable
me to test PLplot against Qt5 (see recent list discussions concerning
Qt5).  The implementation of this epa_build configuration is currently second
on my epa_build agenda.

* The qt4_lite build works fine on Linux but has not yet been tested on
Windows.

* The pango/cairo subset of GTK builds fine on Linux but appears to
have a number of problems on Wine.  I suspect most of those issues
are not due to Wine bugs so I expect they will show up on Microsoft Windows
as soon as someone attempts a build of plplot (as opposed to
plplot_lite) on that platform.

* Currently, the only Plplot configuration tested on Windows is
plplot_lite because of some of the Windows limitations
mentioned above.  Even so, that is already a pretty powerful and
comprehensive test of PLplot on Windows since it involves the Ada,
C++, Fortran, Python, Lua, and Tcl/Tk bindings and examples and many
other PLplot dependencies that are not on the above list of what is
dropped for plplot_lite.

* Currently epa_build has only been tested on Windows using my
(extraordinarily slow) MinGW/MSYS/Wine platform for the plplot_lite
case.  The Wine developers view any deviation from Microsoft Windows
behaviour as a Wine bug.  So since it is unlikely that I am by
accident taking advantage of some Wine bug to make this work, it
should be trivial (and more than an order of magnitude faster than the
Wine case) to follow what I have done for the MinGW/MSYS/Microsoft
Windows case _if_ the bash.exe environment variable approach I
document in cmake/epa_build/README is religiously followed. I also
believe it should be straightforward to make the plplot_lite case work
on the Cygwin platform and also a Windows platform consisting of the
combination of MSYS (bash.exe and other MSYS tools are required for
testing PLplot but will not be used for building it in this case) and
MSVC.

* The epa_build of octave has not been configured.  Octave has an
enormous number of dependencies (much worse than PLplot), and I have
no experience building octave.  So I have decided to indefinitely put
off working on this epa_build configuration.  As a result, the octave
component of the plplot epa_build is currently disabled both for
plplot and plplot_lite, and it will likely be a long time before this
limitation is removed unless someone else is motivated to 
make this work.

Alan
__________________________
Alan W. Irwin

Astronomical research affiliation with Department of Physics and Astronomy,
University of Victoria (astrowww.phys.uvic.ca).

Programming affiliations with the FreeEOS equation-of-state
implementation for stellar interiors (freeeos.sf.net); the Time
Ephemerides project (timeephem.sf.net); PLplot scientific plotting
software package (plplot.sf.net); the libLASi project
(unifont.org/lasi); the Loads of Linux Links project (loll.sf.net);
and the Linux Brochure Project (lbproject.sf.net).
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Linux-powered Science
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