Re: Compiling SWT application with GNU gcj

[Andrew Haley <aph at redhat dot com>]

Michael Koch writes:
 > On Mon, Oct 10, 2005 at 11:03:02PM +0200, Andrea wrote:
 > > Hi all,
 > > I'm trying to compile a simple SWT application (nothing more than a demo
 > > app) with gcj but I'm having some problems in the linking phase.
 > > 
 > > This is what I do to compile:
 > > 
 > > -----------------------------------
 > > nivox@host:~/Test/$ gcj -fjni -c --classpath=$SWT_HOME/swt.jar
 > > test/swt/Test.java
 > > 
 > > nivox@host:~/Test/$ ls
 > > test Test.o
 > > 
 > > nivox@host:~/Test/$ gcj --main=Test ./Test.o -lswt-gtk-3138
 > > /tmp/ccf5eyYv.o(.text+0x12): In function `main':
 > > : undefined reference to `_Jv_Compiler_Properties'
 > > /tmp/ccf5eyYv.o(.text+0x2b): In function `main':
 > > : undefined reference to `Test::class$'
 > > /tmp/ccf5eyYv.o(.text+0x30): In function `main':
 > > : undefined reference to `JvRunMain'
 > > ./Test.o(.text+0x10): In function `test::swt::Test::main(JArray*)':
 > > : undefined reference to `_Jv_InitClass'
 > > ./Test.o(.text+0x1f): In function `test::swt::Test::main(JArray*)':
 > > : undefined reference to `org::eclipse::swt::widgets::Display::class$'
 > > ./Test.o(.text+0x24): In function `test::swt::Test::main(JArray*)':
 > > : undefined reference to `_Jv_AllocObjectNoFinalizer'
 > > ./Test.o(.text+0x2e): In function `test::swt::Test::main(JArray*)':
 > > : undefined reference to
 > > `org::eclipse::swt::widgets::Display::Display[in-charge]()'
 > > ./Test.o(.text+0x42): In function `test::swt::Test::main(JArray*)':
 > > : undefined reference to `org::eclipse::swt::widgets::Shell::class$'
 > > ./Test.o(.text+0x47): In function `test::swt::Test::main(JArray*)':
 > > : undefined reference to `_Jv_AllocObjectNoFinalizer'
 > > ...
 > > -----------------------------------
 > > 
 > > I have compiled with success a java program without graphic... so gcj is
 > > supposed to work properly.
 > > 
 > > Gcj --version return this:
 > > gcj-4.0 (GCC) 4.0.0 20050301 (prerelease) (Debian 4.0-0pre6ubuntu7)
 > > 
 > > I have the same problem on another machine with gcj 4.0.2 from Debian
 > > unstable (ppc).
 > > 
 > > Have someone any hint for me?
 > 
 > Make sure libgcj6-dev and libgcj-dev are installed. These are needed
 > when compiling to native (not when compiling to bytecode).

Oh dear.  So, it's possible to install gcj but not libgcj when using
Debian packaging.  I wonder if perhaps we could make gcj spit out an
error message when libgcj is missing, telling people that perhaps they
need to install libgcj.

Otherwise we are going to see a *lot* of reports like this one.

Andrew.