Access Violation TPQConnection := False

[LzMan]

Normally, I use the debugger of Lazarus. I wrote in a previous post that the AV also happens when I attach the Visual Studio debugger to the standalone executable. The AV is definitely there. The AV is also there in x64dbg.

[rvk]

Normally, I use the debugger of Lazarus.

What debugger is that exactly?
Lazarus can have several.
Gdb or fp-debugger.

And depending on the debugger it's also important which debugger options you set.

But so it's not the ide itself that's the problem but the attachment of a debugger.

I'm not familiar with x64dbg or de debugger from VS so I don't know if there are known issues there.

[LzMan]

Can we stay on topic, please? How can I debug the LCL?

[rvk]

Can we stay on topic, please? How can I debug the LCL?

You would need to rebuild Lazarus with debug option.
https://forum.lazarus.freepascal.org/index.php?topic=61774.0

The problem is that you probably don't want LCL because the database function is not from LCL but from FPC. You could build both with debugging on to be able to trace through the source.

How did you install FPC and Lazarus?
You could try fpcupdeluxe but I'm not sure how to set the debug options (never used fpcupdeluxe).

[Zvoni]

Instead of waxing philosophical questions, TS should try a barebone sample-app without „visuals“ (read: simple console app), and check if his AV still appears (my bet is: no, it won’t AV if done correctly)

[jcmontherock]

With MySQL i'm using: 

Code: Pascal  [Select][+][-]

1. if Connection1.Connected then Connection1.Close;

without problem...