>My research on atoms is based on my need to communicate a bit with another application (written in delphi). May it be that I have not seen DDE as THE solution just because it was laying there at my feet?

It's possible <g>. Dunno enough about delphi's DDE-capabilities.
AND not about your specific needs - amount of data, messaging latency and so on...

>
>Are there any disadvantges?
Speaking from maintaining a fpw app to a vfp app:

1) you have to write the "server" setup code.
I've read it (developed by prev. devl) and changed a few bits -
no rocket science, but probably means searching for VERY old examples for you.

2) Hearsay: In testing on one machine DDE just wouldn't work
Therefore a backdrop was written via timers/event loops and a semaphore file
This code was "consolidated" and the result was ugly.

I think the other developers had no idea what was REALLY wrong.

I've never encountered the "not working machine" and
just concentrated on eliminating more than a few bugs AND
made a few calls in between asynch:
which was a great help for perf in some tight situations.

3) DDE is "legacy". ActiveX is that nowadays as well <g>.
Any chance of implementig activeX references between the apps ?
This would probably be "safer" in the very long run, but I'ld
probably get one version out of the door ASAP and worry/fix later.

What to choose ?
If you need "callbacks": they are a documented(!) part of DDE <vbg>.
If you just have to move data and wait for the other process to finish:
activeX might be enough, tables might be enough:
go with the easiest, speed shouldn't be a problem for single calls
(granularity of timers reliable at 50ms).

How much budget and rope from managment do you have ?
What OS to support ? How's the install ?
How reliable are your testers ?
Do you have to explain to co-developers or write tech docs <g>?

HTH

thomas