fortran Java Interface 1

[ArmenD]

hi,
I have fortran code that needs java interface. I heard jni is way to go.

are there any good src code examples that show how this is done.
both small and meduim/large src code examples are welcome.

i've been reading the api, but i need to c examples.
this is sort of a high priority project, so plz any input is welcome.

thanks in advnace,
armen

 

[ArmenD]

does anyone know how to pass primitive data types such as int, char from fortran to C and from C to fortran using JNI?

 

[xwb]

C to Fortran is very implementation dependent unless you have Fortran 2003. Which platform/compilers are you using?

 

[ArmenD]

ibm pc, using f77.
basically i have a fortran statistical package that i need to provide a graphical user interface for I/O.
so i decided to do it in java using JNI.
so c is the intermediary language that i need to use.
I am at the step of implementing native methods and I want to know if ppl have examples of parameter passing and function return types from c to fortran?

i also want to know how to create shared libraries(.dll) from the c and fortran code i have under windows/pc. there r insturctions for unix but i want those for windows.

 

[xwb]

Sorry - you need to be more specific. There are lots of different F77 compilers and every one has a different interface mechanism. I know about G77 (GNU) but I don't know about the others like Lahey, Salford, Watcom etc.

 

[ArmenD]

so for gnu(g77), would you happen to know the instructions for creating shared libraries with c/fortran?

any src code examples or compilation instructions would be appreciated.

 

[ArmenD]

So suppose my fortan program has (5 functions)
and I use JNI method to make use of existing fortran code
here is my ?,

should i declare prototypes of all 5 fortran functions in c or
should i declare only the topmost entry method(main) of fortran?

my inclination is that if my fortran main method has access to all variables in program, then i only need the topmost fortran main prototype funciton to be declared in c.
is this correct?

 

[ArmenD]

so all the examples I have seen, c calls a fortran subroutine.
Can c call a fortran program?

 

[xwb]

If you call a program i.e. via system, then the two programs will have to communicate through a file. I've only used Fortran calling C: not the other way round. Normally, it is easier to rewrite the code if it is the other way round. There are Fortran to C translators (f2c) which will do most of the work for you.

 

[ArmenD]

hi,
by the way thanks for your help thus far, but I have a quick follow up ?, regarding "Can c call a fortran program?"

ok so can't I write a 1 line c code that calls fortran program and the fortran program continues till it ends, and then returns to c code that called it and the program ends.

I dont know if there is a need for the c program and the fortran program to communicate. after all the only reason why i am using c is b/c java JNI method needs it. Is my understanding of the process thus far correct?

thanks again,
armen

 

[xwb]

Yes - it is basically Fortran calling C calling Java. Come to think of it, I don't think I've ever had C calling Fortran. I've always translated the Fortran into C and had it purely in C. It is only in graphics that I've had to use multiple languages.