Re: Example on JNI compilation

[John Calcote]

On 4/20/2009 3:49 PM, Peter O'Gorman wrote:
> John Calcote wrote:
>    
> > On 4/18/2009 3:08 PM, LCID Fire wrote:
> >      
> > > I'm currently stuck with compiling a JNI library, which java does not
> > > recognize. I'm not too sure about what options I have to provide to
> > > automake and which are already builtin. Does anybody know an example
> > > of how a jni lib is built using automake?
> > >        
> > There are basically two steps to building JNI libraries:
> >      
>
> Note that on Mac OS X 10.4 and earlier, java will not load modules that
> do not have a ".jnilib" extension, so you should add somewhere in
> configure.ac, something like:
>
> case $host_os in
> *-darwin*)
>     JNI_EXTRA_LDFLAGS="-shrext .jnilib" ;;
> esac
> AC_SUBST(JNI_EXTRA_LDFLAGS)
>
> then in your Makefile.am you can have:
> mylib_la_LDFLAGS = -module -avoid-version $(JNI_EXTRA_LDFLAGS)
>
> Peter
>    
Thanks Peter, I didn't know this. I guess it won't be long before this 
isn't really an issue for newer macs, as 10.6 will probably be released 
in June, thereby bringing 10.4 to end-of-life state. However, there will 
still be plenty of older mac users out there.

I might as well ask this question here: We build a regular C/C++ shared 
library, and link our JNI stubs right into it, exporting the JNI 
interfaces right along side the native library interfaces. It seems to 
work well on the platforms we've tried it out on, and it saves a 
library. In fact, we do the same thing with our C# (mono) interfaces, so 
this library has a hefty exported API.

Besides the issue you pointed out above where JNI libs require a 
specific extension, do you know of any other issues with doing this sort 
of thing?

Thanks in advance,
John