swi-prolog-jpl: library jpl fails to load

[Martin Günther]

Binary package hint: swi-prolog

I am using Ubuntu Lucid Lynx (10.04). Trying to load the jpl library fails with:

ERROR: /usr/lib/swi-prolog/library/jpl.pl:4638:
 Exported procedure jpl:jpl_c_lib_version/1 is not defined

Note that calling Prolog from Java works (packages/jpl/examples/java), but not the other way around (packages/jpl/examples/prolog). Same result with both java-6-openjdk and java-6-sun, which is not surprising giving that Google thinks that this error message has something to do with Prolog having a problem with libjpl.so.

However, when I use swi-prolog 5.11.1 built from source, everything works as advertised. I have 5.8.0 installed from the official Ubuntu packages, and 5.11.1 from source (at /usr/local/...). Uninstalling either doesn't change the behaviour.

Here is the output, along with the appropriate environment variables:

== using 5.8.0 official ubuntu package: ==
LD_LIBRARY_PATH=/usr/lib/swi-prolog/lib/amd64:/usr/lib/jvm/java-6-sun-1.6.0.20/jre/lib/amd64/:/usr/lib/jvm/java-6-sun-1.6.0.20/jre/lib/amd64/server/
SWI_HOME_DIR=/usr/lib/swi-prolog
PATH=/home/martin/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/home/martin/bin
CLASSPATH=.:/usr/lib/swi-prolog/lib/jpl.jar
JAVA_HOME=/usr/lib/jvm/java-6-sun/

Using LD_PRELOAD=/usr/lib/swi-prolog/lib/amd64/libjpl.so

% library(swi_hooks) compiled into pce_swi_hooks 0.00 sec, 3,616 bytes
Welcome to SWI-Prolog (Multi-threaded, 64 bits, Version 5.8.0)
Copyright (c) 1990-2009 University of Amsterdam.
SWI-Prolog comes with ABSOLUTELY NO WARRANTY. This is free software,
and you are welcome to redistribute it under certain conditions.
Please visit http://www.swi-prolog.org for details.

For help, use ?- help(Topic). or ?- apropos(Word).

?- [library(jpl)].
% library(error) compiled into error 0.01 sec, 17,688 bytes
% library(lists) compiled into lists 0.01 sec, 42,616 bytes
ERROR: /usr/lib/swi-prolog/library/jpl.pl:4638:
 Exported procedure jpl:jpl_c_lib_version/1 is not defined
% library(jpl) compiled into jpl 0.03 sec, 662,512 bytes
true.

== using pl-5.11.1 built from source: ==
LD_LIBRARY_PATH=/usr/local/lib/swipl-5.11.1/lib/x86_64-linux:/usr/lib/jvm/java-6-sun-1.6.0.20/jre/lib/amd64/:/usr/lib/jvm/java-6-sun-1.6.0.20/jre/lib/amd64/server/
SWI_HOME_DIR=/usr/local/lib/swipl-5.11.1
PATH=/home/martin/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/home/martin/bin
CLASSPATH=.:/usr/local/lib/swipl-5.11.1/lib/jpl.jar
JAVA_HOME=/usr/lib/jvm/java-6-sun/

Using LD_PRELOAD=/usr/local/lib/swipl-5.11.1/lib/x86_64-linux/libjpl.so

% library(swi_hooks) compiled into pce_swi_hooks 0.00 sec, 3,856 bytes
Welcome to SWI-Prolog (Multi-threaded, 64 bits, Version 5.11.1)
Copyright (c) 1990-2010 University of Amsterdam, VU Amsterdam
SWI-Prolog comes with ABSOLUTELY NO WARRANTY. This is free software,
and you are welcome to redistribute it under certain conditions.
Please visit http://www.swi-prolog.org for details.

For help, use ?- help(Topic). or ?- apropos(Word).

?- [library(jpl)].
% library(error) compiled into error 0.00 sec, 18,224 bytes
% library(lists) compiled into lists 0.00 sec, 44,688 bytes
% library(jpl) compiled into jpl 0.03 sec, 697,576 bytes
true.

[Martin Günther (launchpad-domain-the-phoenix)]

BTW, I am on a AMD64 system.

Linux caprica 2.6.32-22-generic #36-Ubuntu SMP Thu Jun 3 19:31:57 UTC 2010 x86_64 GNU/Linux

[Kilian Evang (kevang)]

Unless I'm mistaken, the current version of jpl.pl tries to add jpl.jar to the classpath automatically as soon as jpl.pl is loaded. It expects to find jpl.jar in $SWI_HOME/lib.

The package should be updated to put jpl.jar there.

[Martin Günther (launchpad-domain-the-phoenix)]

I don't believe it has anything to do with jpl.jar, but instead with libjpl.so. Anyhow, this package seems not to be maintained any more.

[Kilian Evang (kevang)]

You're right, I was mistaken, the issue I mentioned was different, maybe nonexistent (I can't reproduce it now).

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[NoBugs! (luke32j)]

Same happens in the latest Ubuntu version, apparently it wasn't compiled with the right library settings?

I had to compile the software as described here, to make a working installable package.
https://code.google.com/p/javanaproche/wiki/HowToJPL