return values of device driver routines

[hwulf at et-inf.fho-emden.de]

Hi there,

how do the return values work in the RTEMS device driver routines  
(open, close, read, write, ioctl)?

When I wanted to return the value (-1), do I have to execute "return  
(-1);" or do I have to set a appropriate variable of the argument  
structures (rtems_libio_open_close_args_t, rtems_libio_rw_args_t,  
rtems_libio_ioctl_args_t)?

Thank you very much and kind regards,
  Hank