iOS Phone threading problem (2 replies)

I have a problem but don't need a resolution. I need to find out how to get something meaningful back in a live situation (on the device) as the code is failing and I cannot find out why although I know the line it is failing on.

In short it is failing on HCreateMoveableReplica.

Here is the sequence of events:

Thread 0 runs a LOCAL Procedure in Thread 1. That procedure then calls a GLOBAL procedure run in Thread 0 (it has to do that as a file is created in Thread 0 required by HCreateMoveableReplica run in Thread 1). This is when the code fails.

What is interesting is that exactly the SAME code runs in Windows, Android and iOS Tablet and ONLY fails in iOS Phone 11.1.3

Using any method such as Display, Debug to a File or trapping the event "somewhere", how can I find out exactly why this command is failing? I know it is something to do with threading as running in XCode gives me a sort of hint that a Thread issue has happened. But I need to get a meaningful message from the event using PCSoft terminology.

But the problem is, I believe, that any error trapping fails because of the return to thread 0 where it fails not in thread 1.

I hope that makes some sort of sense but basically because of threading the event is failing but not reporting back.

Thx.