ested in.
    </p>

    <p>
      Perhaps the trickiest issue here is the difference in conventions
      for dealing with a scalar argument passed to a function.  A C function
      will typically expect such an argument to be passed by value; it is also
      possible to pass the quantity by reference, although this is more unusual.
      If the C function already exists and cannot be changed by the user,
      then this can present a difficulty.  The reason is that FORTRAN77
      only provides the optio