[SOLVED] Detect if a memory is valid

[Thaddy]

The best way to evaluate that is a repeatable crash.... That is not a joke. You can take precautionary measures  to avoid it, but not much else.

[Okoba]

I needed the laugh, thank you.

TO summarize I want to know two things now:
1- A question I have is that in debug mode, Lazarus uses exception handling that leads to the message box. Where was it set?
2- Is it safe swapping exception handling functions in the the previous code I posted, using try finally?

[PascalDragon]

1- A question I have is that in debug mode, Lazarus uses exception handling that leads to the message box. Where was it set?

It's triggered by the debugger, not the application.

2- Is it safe swapping exception handling functions in the the previous code I posted, using try finally?

No, because that is not thread safe. Just do as Thaddy said: just access the memory and trigger a potential exception and catch that using try … except.

[Okoba]

It's triggered by the debugger, not the application.

Interesting, so the GDB or FPDebugger act as the exception manager before it gets to the program.

No, because that is not thread safe. Just do as Thaddy said: just access the memory and trigger a potential exception and catch that using try … except.

My question controlling that exception without SysUtils. Now that I found it thanks to you, and my program is not threaded, I can have my way.

Thank you all.

[Okoba]

@PascalDragon Is there a way to tell debugger, to not control the exception? I still like to have the debug info, without the debugger middling in exception handling.

[PascalDragon]

It's triggered by the debugger, not the application.

Interesting, so the GDB or FPDebugger act as the exception manager before it gets to the program.

It's the purpose of a debugger to be able to catch exceptions of an application so that the developer can investigate them.

No, because that is not thread safe. Just do as Thaddy said: just access the memory and trigger a potential exception and catch that using try … except.

My question controlling that exception without SysUtils. Now that I found it thanks to you, and my program is not threaded, I can have my way.

That doesn't change that changing these functions is not thread safe.

@PascalDragon Is there a way to tell debugger, to not control the exception? I still like to have the debug info, without the debugger middling in exception handling.

Project -> Project Settings -> Project Settings -> Language Exceptions. Add the class name to the list, though I don't know whether the debugger does special checks that the class inherits from Exception.

[Okoba]

Thank you!