title: Input and output arguments for ctypes
body: <p>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.</p>
  
  <p>The f90 code starts as:</p>
  
  <pre><code>subroutine DataSub (Data_input,da,db,dy)
  
      double precision, intent(in) :: Data_input(9)
      double precision, intent(out) :: da,db,dy
  </code></pre>
  
  <p>How do you define the input and output arguments for this case in ctypes?</p>