Re: Static executables

[Andrzej Bialecki <ab at getopt dot org>]

David Daney wrote:
> Tom Tromey wrote:
> > It would be helpful if someone wrote a page for the gcc wiki about
> > static linking.
>
> Like this:?
>
> http://gcc.gnu.org/wiki/Statically%20linking%20libgcj

I tested it now with some simple classes, it works well ... but I 
suspect I'm still missing something, because my target application 
doesn't work. I.e. it compiles and links ok, but fails during runtime.

I'm trying to compile a tutorial application for Charva 
(http://www.pitman.co.za/projects/charva/). The library consists of a 
JAR and some JNI parts, which use NCurses. When linking dynamically, 
they are put in an libTerminal.so, and then the toolkit loads them with 
System.loadLibrary("Terminal"). Now, with static linking, I thought this 
no longer is needed, because I'm linking directly with these objects, so 
I skipped the call to loadLibrary. But the application refuses to work, 
throwing an UnsatisfiedLinkError to one of the symbols from that 
library... Of course, if I keep the call to loadLibrary, the system 
cannot find the library, so it dies anyway.

Here's the procedure I followed to prepare the library JAR, and the JNI 
part:

# this depends on ncurses, but we're not linking now
gcj -c Toolkit.c -fjni -findirect-dispatch -o Toolkit.o

gcj -c charva.jar -fjni -findirect-dispatch -o charva.o

And then the magic incantation, copied from the Wiki (I put my objects 
on separate lines for readability):

gcj -classpath charva.jar -c Test.java -o Test.o
gcj -classpath charva.jar --main=Test -save-temps Test.java
gcc -o Test Test.o Testmain.i -shared-libgcc -Wl,-non_shared -lgcj \
   charva.o Toolkit.o \
   -Wl,-call_shared -lsupc++ -Wl,--as-needed -lz -lpthread -lc -lm -ldl \
   -lncurses \
   -Wl,--no-as-needed 

The application is linked properly, but then when executed, where it 
calls the Charva library initialization, it fails because it cannot find 
the  native function from Terminal.o ... What to do now?

Some other observations: I didn't need to link -lgcc_s, in fact I don't 
have it anywhere... Also, I believe there are no ready-made packages for 
Fedora Core that contain libgcj.a, so I had to build it from the source. 
And finally, the executable size is, well .. impressive, ~9MB for a 
Hello World.

--
Best regards,
Andrzej Bialecki     <><
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