Re: GCJ and C++ (calling Java from C++)

[Andrew Haley <aph at redhat dot com>]

Lothar Werzinger writes:
 > On Monday 05 December 2005 03:39, Andrew Haley wrote:
 > > Lothar Werzinger writes:
 > >  >From what I learned reading about CNI calling methods on interfaces
 > >  >requires a special dispatch table called otable.
 > >
 > > I don't think so.  As far as I'm aware the otable is only ever
 > > involved when a file has been compiled with -findirect dispatch.  CNI
 > > doesn't use indirect dispatch.  Without indirect dispatch, we'd expect
 > > the otable to be null.
 > 
 > The jar and the Java file are compiled with -findirect-dispatch, so
 > I think having a null otable is bad.

CNI doesn't use indirect dispatch.

 > You should be able to see that in the build.xml in the project I
 > sent you last time.

What you sent me last time didn't build.  I tried for a while to get
it to build then gave up.

 > > Which line?  Does the failure occur in the call to get_name?
 > 
 > As said in previous postings it fails either in 
 > 
 >     JvInitClass(LibraryTestClass);
 > 
 > or in
 > 
 >     String * p_name = p_library->getName();
 > 
 > if I comment out the JvInitClass. If I do comment it out I get the following 
 > console ouput from some println's I do in the code:
 > 
 >      [exec] LibraryTest::class$.getName() = test.LibraryTest
 >      [exec] p_libraryTest->getClass()->getName() = test.LibraryTest
 >      [exec] Library::class$.getName()  = 
 > org.eclipse.emf.examples.extlibrary.Library
 >      [exec] p_library->getClass()->getName() = 
 > org.eclipse.emf.examples.extlibrary.impl.LibraryImpl
 > 
 > The LibraryImpl is the class that implements the Library interface.
 > 
 > > What is the faulting instruction?
 > >
 > > The problem here is that we only have tiny snippets of information to
 > > go on.
 > 
 > As for the faulting instruction, what ezactly do you want me to do
 > to find that? Send you the asm again? GDB output - if you tell me
 > which commands to execute in gdb I would be happy to do
 > that. Please tell me exactly how I can help you finding the
 > problem. I can also send you the full tar again if you want to try
 > to reproduce it by yourself.

It doesn't build.

If you can put a buildable tar somewhere I'll have a look.  I have all
of Eclipse installed, and all of ant, etc, etc, so you don't have to
send any of that.

Andrew.