Ada and EDF in Win32?

Ada and EDF in Win32?

[Günther Wimpassinger]

Hello,

I just started learning Ada and try to implement a small tasking example 
(some homework). I would like to use EDF scheduling, but if I try
"with Ada.Dispatcher.EDF" I get an errormessage during compilation:
"EDF is not supported in this configuration"

I tried to add "pragma Task_Dispatching_Policy(EDF_Within_Priorities)". 
In the .adb sourcfile and in the "gnat.adc" config file. But this
does not change anything.

Is EDF only available on systems, where the OS/Environment supports EDF 
or is it possible to use EDF in Ada on standard PC OSs (like GNU/Linux 
or Windows without realtime extensions).

Tried in
Ubuntu 9.04 with the toolset from their software repositories and
Windows XP SP3 with GPS 4.3.1 (20090114)


bye
Guenther

Re: Ada and EDF in Win32?

[AdaMagica]

> I tried to add "pragma Task_Dispatching_Policy(EDF_Within_Priorities)".

I've never used this policy, but the name is EDF_Across_Priorities.

Re: Ada and EDF in Win32?

[Günther Wimpassinger]

AdaMagica schrieb:
>> I tried to add "pragma Task_Dispatching_Policy(EDF_Within_Priorities)".
> 
> I've never used this policy, but the name is EDF_Across_Priorities.

Excuse me, EDF_Across_Priorities is the one I used in my examples. This 
was a mistake in the message.

Thanks
Guenther

Re: Ada and EDF in Win32?

[sjw]

On Jun 19, 1:36 am, Günther Wimpassinger <marsianre1...@gmx.net>
wrote:

> I just started learning Ada and try to implement a small tasking example
> (some homework). I would like to use EDF scheduling, but if I try
> "with Ada.Dispatcher.EDF" I get an errormessage during compilation:
> "EDF is not supported in this configuration"
>
> I tried to add "pragma Task_Dispatching_Policy(EDF_Within_Priorities)".
> In the .adb sourcfile and in the "gnat.adc" config file. But this
> does not change anything.
>
> Is EDF only available on systems, where the OS/Environment supports EDF
> or is it possible to use EDF in Ada on standard PC OSs (like GNU/Linux
> or Windows without realtime extensions).

I assume you're using GNAT. The header of a-disdef.ads in GNAT GPL
2009 on Mac OX X (find this in GPS by selecting Help > GNAT Runtime >
Ada 2005 > Ada > Dispatching > EDF) says

--  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.