-- --
-- S p e c --
-- --
--- Copyright (C) 1998-2005 Free Software Foundation, Inc. --
+-- Copyright (C) 1998-2007, Free Software Foundation, Inc. --
-- --
-- GNARL is free software; you can redistribute it and/or modify it under --
-- terms of the GNU General Public License as published by the Free Soft- --
-- covered by the GNU Public License. --
-- --
-- GNARL was developed by the GNARL team at Florida State University. --
--- Extensive contributions were provided by Ada Core Technologies Inc. --
+-- Extensive contributions were provided by Ada Core Technologies, Inc. --
-- --
------------------------------------------------------------------------------
-- This package provides low level primitives used to implement clock and
--- delays in non tasking applications on Alpha/VMS
+-- delays in non tasking applications on Alpha/VMS.
-- The choice of the real clock/delay implementation (depending on whether
-- tasking is involved or not) is done via soft links (see s-soflin.ads)
Max_Sensible_Delay : constant Duration :=
Duration'Min (183 * 24 * 60 * 60.0,
Duration'Last);
- -- Max of half a year delay, needed to prevent exceptions for large
- -- delay values. It seems unlikely that any test will notice this
- -- restriction, except in the case of applications setting the clock at
- -- at run time (see s-tastim.adb). Also note that a larger value might
- -- cause problems (e.g overflow, or more likely OS limitation in the
- -- primitives used). In the case where half a year is too long (which
- -- occurs in high integrity mode with 32-bit words, and possibly on
- -- some specific ports of GNAT), Duration'Last is used instead.
+ -- Max of half a year delay, needed to prevent exceptions for large delay
+ -- values. It seems unlikely that any test will notice this restriction,
+ -- except in the case of applications setting the clock at run time (see
+ -- s-tastim.adb). Also note that a larger value might cause problems (e.g
+ -- overflow, or more likely OS limitation in the primitives used). In the
+ -- case where half a year is too long (which occurs in high integrity mode
+ -- with 32-bit words, and possibly on some specific ports of GNAT),
+ -- Duration'Last is used instead.
+
+ procedure Initialize;
+ -- Initialize global settings related to this package. This procedure
+ -- should be called before any other subprograms in this package. Note
+ -- that this procedure can be called several times.
function OS_Clock return OS_Time;
-- Returns "absolute" time, represented as an offset
function Clock return Duration;
pragma Inline (Clock);
- -- Returns "absolute" time, represented as an offset
- -- relative to "the Epoch", which is Jan 1, 1970 on unixes.
- -- This implementation is affected by system's clock changes.
+ -- Returns "absolute" time, represented as an offset relative to "the
+ -- Epoch", which is Jan 1, 1970 00:00:00 UTC on UNIX systems. This
+ -- implementation is affected by system's clock changes.
function Monotonic_Clock return Duration;
pragma Inline (Monotonic_Clock);
- -- Returns "absolute" time, represented as an offset
- -- relative to "the Epoch", which is Jan 1, 1970.
- -- This clock implementation is immune to the system's clock changes.
+ -- Returns "absolute" time, represented as an offset relative to "the Unix
+ -- Epoch", which is Jan 1, 1970 00:00:00 UTC. This clock implementation is
+ -- immune to the system's clock changes.
Relative : constant := 0;
Absolute_Calendar : constant := 1;
Absolute_RT : constant := 2;
- -- Values for Mode call below. Note that the compiler (exp_ch9.adb)
- -- relies on these values. So any change here must be reflected in
- -- corresponding changes in the compiler.
+ -- Values for Mode call below. Note that the compiler (exp_ch9.adb) relies
+ -- on these values. So any change here must be reflected in corresponding
+ -- changes in the compiler.
procedure Timed_Delay (Time : Duration; Mode : Integer);
- -- Implements the semantics of the delay statement when no tasking is
- -- used in the application.
+ -- Implements the semantics of the delay statement when no tasking is used
+ -- in the application.
--
-- Mode is one of the three values above
--
-- Time is a relative or absolute duration value, depending on Mode.
--
- -- Note that currently Ada.Real_Time always uses the tasking run time, so
- -- this procedure should never be called with Mode set to Absolute_RT.
+ -- Note that currently Ada.Real_Time always uses the tasking run time,
+ -- so this procedure should never be called with Mode set to Absolute_RT.
-- This may change in future or bare board implementations.
function To_Duration (T : OS_Time; Mode : Integer) return Duration;
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