LabVIEW
DDE.lib - External subroutine not found
Hello,
I have inherited LabVIEW code which worked on another computer but is throwing errors on this new setup. I am unsure what version of LabVIEW was on the working computer (possibly 2018 professional) but it was windows 10.
The machine I am using is Windows 10, LabVIEW 2021 community. I will have professional by next week - but I don't think this is the issue.
I have copied over the DDE.lib folder to the Addons folder as recommended here:
Archived: Dynamic Data Exchange (DDE) Functions Palette in LabVIEW - NI
However, this did not solve my problem. The image below shows the hierarchy and the relevant DDE vi's. Are they in the correct location?
Let me know if there is anymore information you need, I am still familiarizing myself with LabVIEW but will be going through core 1 next week.
Errors thrown (they are all DDE related):
Regards
Richard
The DDE.llb library makes internally use of a CIN. This CIN has never been recompiled for 64-bit. This means that all DDE functions are broken on 64-bit platforms (and of course on any non-Windows platform too).
Since DDE functions were depreciated in LabVIEW loooong before there was ever a 64-bit version of LabVIEW this is actually very understandable.
You need to install 32-bit LabVIEW to have any chance of using those DDE functions. It then usually works but if it doesn't you have exactly 0% chance of any support. This DDE functionality was developed more than 25 years ago and NI has never made any changes to it since about 1997 since by that time Microsoft has declared DDE to be obsolete technology that was replaced by the much more capable and secure ActiveX functionality (which by now is highly depreciated by Microsoft too in favor of .Net).
@Richard-P wrote:
Perfect, thanks for the detailed response, Rolf. I had no idea it was that old!
It's even older than that. 😀
DDE was a Windows 3.x technology that was already depreciated as soon as Windows 95 was released. However Microsoft left it in there for backwards compatibility reason until today and the Windows Explorer still supports the old DDE interface that lets you control it from other applications. And it still is the default method for many applications to remotely invoke it from Explorer with parameters such as what file to open. But it is obscure and highly under documented by now to the point where nobody in his sane mind would ever consider implementing it in a new application if he would start today.
