Building an app with gcj and readline

Sat Oct 30 13:16:00 GMT 2004

Mark W. asked me to write and "complain" here a bit about the process
of building my app.
Basically, my app builds reasonably well with gcj, and it's not that
hard to figure out. It's fairly similar to how I use gcc.
However, the problems start when I try and link the whole thing with
libreadline-java on my Debian (testing) system. I eventually figured
things out with Mark's patient help on irc, and ended up with the
following:
librl.so: /usr/share/java/libreadline-java.jar
	gcj-3.4 -fjni -fPIC -shared -Wl,-soname,librl.so -o librl.so /usr/share/java/libreadline-java.jar
rlhecl: classes librl.so
	gcj-3.4 -g -o rlhecl --main=com.dedasys.hecl.RLHecl com/dedasys/hecl/*.class -L. -lrl -I/usr/share/java/libreadline-java.jar
and to get it to run correctly, I had to set the LD_LIBRARY_PATH to
include not only the build directory (for "librl.so"), but
/usr/lib/jni
Some things that wouldn't have seemed natural to me to try:
1) -fjni - wouldn't have thunk of it myself.
2) -I/usr/share/java/libreadline-java.jar - didn't I already compile
 that into the shared lib? Seems odd.
3) having to set LD_LIBRARY_PATH is a bit of a pain. It would be nice
 for deployment if that weren't necessary.
Mark mentions that -Djava.library.path=/usr/lib/jni ought to make the
library path part go away, but I'll let him deal with that.
Anyway... I'm really not complaining - Mark asked me to write down
some notes on this stuff, so here they are. I'm really quite happy to
have a free java system to use to hack on my project!
Thankyou for your time,
-- 
David N. Welton
Personal: http://www.dedasys.com/davidw/
Apache Tcl: http://tcl.apache.org/
Free Software: http://www.dedasys.com/freesoftware/
Linux Incompatibility List: http://www.leenooks.com/