Thank you very much.

I have worked further on this. I can confirm that many of QuickOPC do not work from Lazarus, but I unfortunately I was not able to figure out why. The same methods work from other OLE Automation hosts that I have tried.

What's worse, I thought that maybe the problem is caused by the particular new version of Lazarus (1.8.2). But during my tests today, I was not able to make our stuff fully work with Lazarus 1.6.2 (which is what we have tested earlier) either. And that was with QuickOPC 2016.2, and 2018.1.

Sadly, I am unable to help you further at this point. The problem is not on your side. It is either in Lazarus (I believe that's most likely), in QuickOPC, or in a particular incompatibility between the two. But Lazarus is low on the list of tools we target, and we do not currently have resources to investigate this deeper.

Regards

I have started looking to this. I am also getting problems under Lazarus 1.8.2, but they seem somewhat different from what you reported. What is interesting is that *some* of our examples work, but most don't. The one for Read, for example, does not work, and gives EOleException. So far I can only suspect that methods that accept more than one parameter have a problem, but that's just a wild hypothesis. Note that the same methods can be called from other OLE automayion hosts (such as VBScript).

Can you please also answer these questions:

A ) Are you using 32-bit or 64-bit Lazarus?

B ). What happens if you attempt to run specifically following two of our examples? Do they work? If not, what kind of error you get?
- 1) "_ComputerBrowserDialog.ShowDialog.Main"
- 7) "_EasyUAClient.DiscoverServers.Main"

C ) Can you please go to <ProgramFiles>\OPC Labs QuickOPC 2018.1\ExamplesCom\VBScript\WSH\UADocExamples\_EasyUAClient, and type
Does it work? If not, what kind of error you get?

Many thanks

Thank you. Our examples ran OK with the Free Pascal/Lazarus versions indicated in the article.

I will therefore install the version that *you* have, and test on our side.

Please give me some time. I will reply here when I have some update.

Best regards

Actually, we do have these directives in the main program, but not in the units (which contain the actual execution code). Still, it's worth trying.

Thank you for the details.

We are no Free Pascal/Lazarus experts here either. In fact, QuickOPC can be (and is) used from so many tools/languages that it is impossible to cover them all in full.

I can try to install the precise version of Lazarus that you are using, and see if I can reproduce the problem. I actually think that the method does not even get called; but it is weird that the compiler/runtime lists the whole statement as a method name.

Before I do that, may I ask you why you have the directives there?:
And, even if you do have reason to use them in your program later, can you remove them for now, and re-test? This is practically the only thing (besides compiler version) in which your program differs from our example, so I want to rule out that they are the cause. I have read their descriptions and there are some things that look a bit suspicious (= possibly related) about them, I must say.

Best regards

Hello,
I have some additional questions:

1) Are you sure that you have installed QuickOPC including one of the for "COM development" options (if not, re-run the installer and select the proper option on the 2nd page of the Wizard)

2) Have you followed the steps described here? kb.opclabs.com/First_experiences_using_QuickOPC_with_Free_Pascal_(Lazarus)
[edited: Oh, I see, you did]

3) Can you please show more of your program? Specifically, how is the Client variable declared?

Thank you