anchor.diff:  
       logical function is_valid_param(str) result(val)
         ! Check if the parameter string is valid
  +      !
  +      ! str :: parameter string
         character(*), intent(in) :: str
         character(:), allocatable :: tmp
   
  
positive.code:   end subroutine config_get_logical
  
    subroutine config_get_param_str(param_name, str, found)
      character(*), intent(in) :: param_name
      character(*), intent(out) :: str
      logical, intent(out) :: found
  
negative.code: 
      open(newunit=file_unit, file=filename)
  
      ! Second sweep to read in parameter lines from file
      i_param = 1
      do
         read(file_unit, *, iostat=io_err) tmp_readin
  