Re: Using Xt intrinsics with Ada?

[Stephen Leake <stephen.a.leake.1@gsfc.nasa.gov>]

J�rgen Grigat <juergen.grigat@avitech.de> writes:

> Hi,
> 
> we are developing a program in Ada that has connections to other processes by
> sockets. The calls are done in Ada by using interfaces to C library functions.
> In order to avoid polling we wonder if we can use the event mechanism of X
> Toolkit  Intrinsics. 

This seems an awkward approach. You are using a windowing system to
get tasking; just use Ada tasking!

Allocate one task for each socket connection, that does blocking reads
and writes to the socket. Then have a central task that rendezvous
with the per-socket tasks.

You will need a runtime that blocks at the task level, not the process level.

> So we created a task which is calling a C-routine that itself calls
> XtAppMainLoop. The main program is an Ada routine. From the
> functional point of view this seems to work. But we recognize a
> heavy CPU load even there is no traffic at the connection.

I'm not sure, but I would bet that XtAppMainLoop is polling, looking
for events! So you haven't accomplished anything.

> Has anyone experience in using X Toolkit events in Ada tasking
> programs?
> 
> Thanks for any hints.
> 
> J�rgen

-- 
-- Stephe