Re: object ada, visual c and tasking combined.

[john donoghue <donoghue@chariot.net.au>]

Nick Roberts wrote:

> On Fri, 15 Feb 2002 18:39:49 +1030, john donoghue <donoghue@chariot.net.au>
> strongly typed:
>
> >...
> >... It seems to work ... next problem .... The visual c windowing stuff
> >is in its own task, and there is also another C task that needs to wait
> >on an ada function to return with data - but everytime I call the
> >"pointered" functions from these tasks the app spits the dummy (
> >terminates with a exception that provides no name or message or
> >anything. )
> >I am guessing that you cant call the ada functions from the other C
> >tasks since they are in other tasks to the ada functions :) ... but is
> >there a way around it?
>
> What do you mean by "another C task"? Do you mean a Windows thread, or do
> you mean a separate process (as in execXX etc.)? In either case (as best I
> recall) Windows, since threads permit options regarding memory sharing (and
> your Ada may take advantage of these options), I suspect the cross-'task'
> calls fail because they cause code to try to access memory that it it is
> not permitted to.
>
> You may hate this suggestion, but my suggestion to you would be to
> modularise your application at a different (higher) level, e.g. COM.
>
> You could make your Ada 'engine' into a stand-alone program whch is a COM
> server, and the VC front-end into a COM client. I am no expert on Windows
> COM, but I think the stuff on AdaPower should give you most of what you
> need to do it. I think in the end you'd find this to be a better solution.
>
> Best of luck!
> --
> Nick Roberts

The C task was a windows thread.
The data beging passed around could have been anything - it didnt matter even
if I never used the value being passed in. Just calling the ada code from
another windows task caused problems.

I gave up on MFC and am using some c++ classes I have written previously that
use just the basic win32.
These dont have any tasks created for messages pumps or anything, and so
allows me to create a task in ADA that processes the message loop and allows
me to keep all tasks as ada ones.
... no more unknown application closing now :)

Thanks all.