Re: [igraph] Igraph with JNI

[Gang Su]

And Tamas,

There's an igraph.dll in the R package, i tried to build the tutorial  
program using visual studio express commandline compiler cl, and it  
doesn't work. I got LINK1107 Error. After some research I found that  
under windows, when a dll file is built, a lib file is also presented.  
So when compiling, the link should link to igraph.lib instead of  
igraph.dll.

I do want to spend sometime on this. Even just port a few functions to  
java, this will at least provide some samples and tutorials for other  
people to begin with.

Thank you very much!

Gang


Quoting Tamas Nepusz <address@hidden>:

> Hi Gang,
>
> > I am thinking about trying to bridge igraph with JAVA via JNI on  
> > windows. The way how JNI works is to link Java via JNI to native C  
> > functions. The C source is complied to a shared library DLL file.
> >
> > Does anyone have worked on this before?
> Yes, I tried it once, but only as a proof-of-concept, so I pretty  
> much abandoned the project after I convinced myself that igraph  
> could be used from Java using JNI had someone took the effort to  
> develop a proper interface. So yes, it's pretty much doable, but not  
> straightforward at all. The reason is twofold: first, using JNI  
> means that you have to write a lot of "glue code" between igraph and  
> Java (pretty much all igraph data types must have a Java counterpart  
> and you have to write the conversion code in C); second, there are  
> some calling conventions in igraph that cannot be easily reproduced  
> in Java (i.e., functions using additional arguments to _return_  
> results). I started adapting the interface generator we use to build  
> the R interface to be able to generate C glue code for the Java  
> interface, but it's very far from being finished.
>
> > where the The directory after the -I switch is the one containing  
> > the igraph.h file, while the one following -L should contain the  
> > library file itself, usually a file called libigraph.so,  
> > libigraph.a or igraph.dll
> > "Quote"
> >
> > Where actually I can find this igraph.dll in the igraph R package.
> I don't know for sure (that's Gábor's part), but I guess nowhere.  
> The thing is that there are two ways to include igraph in your  
> project: static linking (in which case you don't need the igraph DLL  
> as everything that's in the DLL is built directly into your  
> application) or dynamic linking (where you need the DLL as your app  
> contains only references to igraph calls). I think the R interface  
> is built statically, so you won't find a DLL there. JNI only  
> supports dynamic linking, so you need the DLL. To build the DLL, you  
> have to build the library from the C source code either in Visual  
> Studio or in MSYS.
>
> > So my question is if I compile a c file using igraph librarys, and  
> > it can be compiled successfully, will it be able to run standalone?
> If you link it statically, it will work. If you link it dynamically,  
> it will require the DLL. See the corresponding Wikipedia entries as  
> a starting point:
>
> http://en.wikipedia.org/wiki/Static_linking
> http://en.wikipedia.org/wiki/Dynamic_linking#Dynamic_linking
>
> --
> Tamas



Gang Su

PhD student
Bioinformatics training track
Program in Biomedical Sciences
University of Michigan, Ann Arbor
MI, 48105, U.S.A.