From: dbotton@hotmail.com
Subject: Re: Tasks and C/C++ code.
Date: 1998/11/11
Date: 1998-11-11T00:00:00+00:00 [thread overview]
Message-ID: <72b35b$pll$1@nnrp1.dejanews.com> (raw)
In-Reply-To: 729ndu$jfo$1@nnrp1.dejanews.com
I think it would be practical to create a protected type that wrapped your C
function to insure that it is not be run concurrently (if it isn't safe). If
it's safe then just call it as you would any other Ada Procedure/Function.
David Botton
dennison@telepath.com wrote:
> In article <364702E5.F6987321@hiwaay.net>,
> bdorough@phaseiv.com wrote:
> > I am working on a project where we need to call the same C function
> > from multiple tasks. I am wondering how to do this safely. Can I make
> > a generic with my C pragma defined there are do I need to define the
> > prama in the task type so each task will have its own copy of the C
> > function.
>
> If the C function truly isn't safe to call from multiple threads (iaw: relies
> on global data, "static" local declarations, or calls other non-thread safe
> routines) then you have to ensure that calls to it happen from only one
> thread. The safest way to do it is to make *one* server task responsible for
> calling the routine and returning its results. Client tasks rendezvous with
> the server task to request a call to the unsafe C routine. This is the method
> used in at least one set of X/Motif Ada bindings.
>
>
> --
> T.E.D.
>
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next prev parent reply other threads:[~1998-11-11 0:00 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
1998-11-09 0:00 Tasks and C/C++ code Barry L. Dorough
1998-11-09 0:00 ` Mats Weber
1998-11-10 0:00 ` dennison
1998-11-11 0:00 ` dbotton [this message]
1998-11-11 0:00 ` dennison
1998-11-11 0:00 ` Barry L. Dorough
1998-11-11 0:00 ` dennison
1998-11-12 0:00 ` Jerry van Dijk
1998-11-13 0:00 ` Mats Weber
1998-11-18 0:00 ` Samuel Tardieu
1998-11-19 0:00 ` Mats Weber
1998-11-20 0:00 ` Samuel Tardieu
1998-11-23 0:00 ` Mats Weber
1998-11-23 0:00 ` Tom Moran
1998-11-24 0:00 ` Blocking protected ops (was: Tasks and C/C++ code) Mats Weber
1998-11-24 0:00 ` Robert I. Eachus
1998-11-25 0:00 ` Mats Weber
1998-11-25 0:00 ` Jean-Pierre Rosen
1998-11-27 0:00 ` Mats Weber
1998-11-25 0:00 ` Robert I. Eachus
1998-11-26 0:00 ` Simon Wright
1998-11-27 0:00 ` David Botton
1998-11-27 0:00 ` Mats Weber
1998-11-27 0:00 ` Tom Moran
1998-11-27 0:00 ` Jerry van Dijk
1998-11-28 0:00 ` Tom Moran
1998-11-29 0:00 ` Tucker Taft
1998-11-30 0:00 ` Simon Wright
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