Question

I am having a problem with formatting my input and output arguments using ctypes in python to access a fortran function in a dll. I can access the library and the function, but am struggling in how to format the arguments.

The f90 code starts as:

subroutine DataSub (Data_input,da,db,dy)

    double precision, intent(in) :: Data_input(9)
    double precision, intent(out) :: da,db,dy

How do you define the input and output arguments for this case in ctypes?

Answer 1

Something like this:

from ctypes import *#just for brevity in this example
input = (c_double*9)()
input[0] = .....
da = c_double()
db = c_double()
dy = c_double()
dll.DataSub(byref(input), byref(da), byref(db), byref(dy))