Re: gnat: Execution_Time is not supported in this configuration

[singo <sander.ingo@gmail.com>]

On Dec 4, 1:10 pm, Georg Bauhaus <rm.dash-bauh...@futureapps.de>
wrote:

> The reason are explained in the GNAT source files.  The ones I have show
> a note, after the © box:
> ------------------------------------------------------------------------------
> --                                                                          --
> --                         GNAT RUN-TIME COMPONENTS                         --
> --                                                                          --
> --                   A D A . E X E C U T I O N _ T I M E                    --
> --                                                                          --
> --                                 S p e c                                  --
> --                                                                          --
> -- This specification is derived from the Ada Reference Manual for use with --
> -- GNAT.  In accordance with the copyright of that document, you can freely --
> -- copy and modify this specification,  provided that if you redistribute a --
> -- modified version,  any changes that you have made are clearly indicated. --
> --                                                                          --
> ------------------------------------------------------------------------------
>
> --  This unit is not implemented in typical GNAT implementations that lie on
> --  top of operating systems, because it is infeasible to implement in such
> --  environments.
>
> --  If a target environment provides appropriate support for this package
> --  then the Unimplemented_Unit pragma should be removed from this spec and
> --  an appropriate body provided.
>
> with Ada.Task_Identification;
> with Ada.Real_Time;
>
> package Ada.Execution_Time is
>    pragma Preelaborate;
>
>    pragma Unimplemented_Unit;

Thanks to all of you for your help!

Still I wonder why it is written in the GNAT reference specification
that the real time annex is fully implemented [1].

"Real-Time Systems (Annex D) The Real-Time Systems Annex is fully
implemented."

According to the ARM 'Execution Time' is part of the real-time annex
[2], so it should be implemented.

So, does "fully implemented" mean that it only in principle is fully
implemented, but that the underlying OS/hardware (in my case 64-bit
Ubuntu-Linux (9.10) on an Intel QuadCore) has to support this features
as well?

Or how do I have to read "fully implemented"?

Best regards

Ingo

[1] http://gcc.gnu.org/onlinedocs/gnat_rm/Specialized-Needs-Annexes.html#Specialized-Needs-Annexes
[2] http://www.adaic.org/standards/05rm/html/RM-D-14.html