Communication with Applicom PCDDE

[Karine]

Hello,

I've made a labview program which communicate with an API via the
Applicom PCDDE. I've made the communication with DDE.

To communicate, I open a DDE channel, send my request (or poke data)
and after, I close the DDE channel.

The program run during 10 days and after the PC crashs (the memory
grows to the maximum of RAM amount). I've phoned Applicom that tells
me that I'll have to release the items, but I haven't found a command
to do that.

Does someone have ever had the same problem ?? What is the solution
from this problem ??

Bests regards,

Karine

[Aaron Marks]

I'll put as a disclaimer that I haven't dealt much with DDE. Its been activeX for quite some time. In fact, if you can use activeX with this application, you might consider switching. At any rate, I'm not sure what they were referring to. There is no item release from the client side in LabVIEW. As I understand it, items are exposed by the DDE server. There is an item unregister if you are making a DDE server, but I don't think that applies. The actual releasing of data items during push poke operations should be done for you behind the scenes. Older versions of LabVIEW had some problems with DDE. If you are using LabVIEW 3.0, I believe there was a leak that was fixed in 3.0.1. There was another DDE leak that wasn't fixed til much later which manifested as
a leak 4kb at at time. If there is a memory leak in LabVIEW, you should be able to detect it using the Profile VI tool. They might have thought you were storing values in memory and not releasing them. Unless you are building really large arrays, this is probably not an issue.

Aaron Marks
National Instruments

[Karine]

Hello,

My version of Labview is 5.1. In my use of DDE, Labview is a client
and not a server.

In the problem that I've described, Labview is not responsible of the
memory leak. It's the Applicom PCDDE that make the memory leak (we log
the Applicom PCDDE memory in windows).

We have contacted Applicom but they don't know the problem. It's for
that that I have post this message.


Best regards,

Karine


Aaron Marks wrote in message news:<506500000005000000C33E0000-998975444000@exchange.ni.com>...
> I'll put as a disclaimer that I haven't dealt much with DDE. Its been
> activeX for quite some time. In fact, if you can use activeX with
> this application, you might consider switching. At any rate, I'm not
> sure what they were referring to. There is n
o item release from the
> client side in LabVIEW. As I understand it, items are exposed by the
> DDE server. There is an item unregister if you are making a DDE
> server, but I don't think that applies. The actual releasing of data
> items during push poke operations should be done for you behind the
> scenes. Older versions of LabVIEW had some problems with DDE. If you
> are using LabVIEW 3.0, I believe there was a leak that was fixed in
> 3.0.1. There was another DDE leak that wasn't fixed til much later
> which manifested as a leak 4kb at at time. If there is a memory leak
> in LabVIEW, you should be able to detect it using the Profile VI tool.
> They might have thought you were storing values in memory and not
> releasing them. Unless you are building really large arrays, this is
> probably not an issue.
>
> Aaron Marks
> National Instruments