RTEMS 4.9.1 On-Line Library

Clock Manager Time and Date Data Structures

RTEMS Ada User's Guide

7.2.2: Time and Date Data Structures

The clock facilities of the clock manager operate upon calendar time. These directives utilize the following date and time record for the native time and date format:

type Time_Of_Day is
   record
      Year    : RTEMS.Unsigned32; -- year, A.D.
      Month   : RTEMS.Unsigned32; -- month, 1 .. 12
      Day     : RTEMS.Unsigned32; -- day, 1 .. 31
      Hour    : RTEMS.Unsigned32; -- hour, 0 .. 23
      Minute  : RTEMS.Unsigned32; -- minute, 0 .. 59
      Second  : RTEMS.Unsigned32; -- second, 0 .. 59
      Ticks   : RTEMS.Unsigned32; -- elapsed ticks between seconds
   end record;

The native date and time format is the only format supported when setting the system date and time using the rtems.clock_get directive. Some applications expect to operate on a "UNIX-style" date and time data structure. The rtems.clock_get directive can optionally return the current date and time in the following record:

type Clock_Time_Value is
   record
      Seconds      : Unsigned32;
      Microseconds : Unsigned32;
   end record;

The seconds field in this record is the number of seconds since the POSIX epoch of January 1, 1970 but will never be prior to the RTEMS epoch of January 1, 1988.

RTEMS Ada User's Guide