[SOLVED] call Fortran90 in C (not C++)

aihaike · 06-05-2009, 01:31 PM

Dear all,

I need to call a Fortran90 function from a C function.
Does anyone know how to do that?
Actually, my Fortran90 function just do anint(x).
I like this Fortran90 feature which I need in C.
If someone knows how to write an equivalent in C that would some the problem.
Anyway, it'd be interesting to know how to call Fortran90 from C.
Thanks in advance,

Eric.

noctilucent · 06-05-2009, 01:49 PM

Hello.

Perhaps it would help if you provided some details about the Fortran90 functionality you need [for those of us who do not know Fortran]. Would macro definitions help you?

Uncle_Theodore · 06-05-2009, 01:52 PM

Is this what you're looking for?

Code:

int anint(double x)
{
  if(x>0)
    return (int)(x+0.5);
  else return (int)(x-0.5);
}

aihaike · 06-05-2009, 08:41 PM

Thanks guys,

In fact the definition is the following:

Quote:

aint(x) integer portion of |x|. Sign same as sign of x.
anint(x) Nearest integer of x.

We have

Code:

 if x>0 anint(x) = aint(x+.5)
 if x<0 anint(x) = aint(x-.5)

So the problem is similar to simulate aint(x) in C in fact.

Note: anint() and aint() get and return real number.
They are different than floor (greater integer <= x) and ceil (least >= x) which also exist in Fortran.

That's why I wanted to call Fortran90 from C.
It's not obvious for me.

Eric.

Uncle_Theodore · 06-05-2009, 08:44 PM

That's exactly the definition I used for my function...

The only difference is the return type. But it's very easy to change if you really need it.

aihaike · 06-05-2009, 08:49 PM

yes, you're right, I'm sorry !!
It works.
Thanks a lot !!

Eric.

jiml8 · 06-07-2009, 12:09 PM

I have not tried it, but I would expect your fortran function to be directly callable like any other function if all the modules (fortran and C ) were compiled with the gcc suite. You probably would have to correctly prototype the fortran function in C, and it could be there would be some linker option that would need to be set.

But it should work.