RTEMS 4.5.1-pre3 On-Line Library

I/O Manager IO_READ - Read from a device

RTEMS Ada User's Guide

16.4.6: IO_READ - Read from a device

CALLING SEQUENCE:

procedure IO_Read (
   Major        : in     RTEMS.Device_Major_Number;
   Minor        : in     RTEMS.Device_Minor_Number;
   Argument     : in     RTEMS.Address;
   Return_Value :    out RTEMS.Unsigned32;
   Result       :    out RTEMS.Status_Codes
);

DIRECTIVE STATUS CODES:

RTEMS.SUCCESSFUL - successfully initialized
RTEMS.INVALID_NUMBER - invalid major device number

DESCRIPTION:

This directive calls the device driver read routine specified in the Device Driver Table for this major number. Read operations typically require a buffer address as part of the argument parameter block. The contents of this buffer will be replaced with data from the device.

NOTES:

This directive may or may not cause the calling task to be preempted. This is dependent on the device driver being invoked.

RTEMS Ada User's Guide