Where can I find the output of the error messages if a program crashes.

There is another program that still is running.
I want to read the error messages automatically if that is possible.

On 2023-09-01 15:43, Rainer Stratmann via fpc-pascal wrote:

Hello,

Where can I find the output of the error messages if a program crashes. There is another program that still is running. I want to read the error messages automatically if that is possible.

I'm afraid that we'd need a bit more information on what is your situation and what you try to achieve. In particular:

1) What kind of an application is your program (console, GUI, ...), under which operating system?

2) You mention that there is another program that is still running - do you mean that the remaining program starts the crashing one and you would like to check the results? If this is the case, how you start the program (Dos.Exec, SysUtils.ExecuteProcess, Process.TProcess, ...)?

3) What do you mean if you say "crashes" - a run-time error? Or a GUI message box stating that the program crashed? Or...?

Tomas

Ah, sorry. I Forgot it totally.

It is a plain console program under Linux.

Yes, the remaining program starts the crashing one and I would like to check the results? Yes, a run-time error was there.

I start the program with a console command.

An unhandled exception occured at $0814EC41:
EAccessViolation: Access violation
$0814EC41
...
...
...

This messages I need to read automatically

Am Freitag, 1. September 2023, 16:13:54 CEST schrieb Tomas Hajny via fpc- pascal:

Rainer Stratmann wrote

Where can I find the output of the error messages if a program crashes. There is another program that still is running. I want to read the error messages automatically if that is possible.

How do you start it? TProcess, Runcommand have piping options.

OK. You still missed to provide information on how you start the crashing program from the remaining program - certain approaches don't allow simple access to the result (e.g. checking whether it's still running or accessing the process exit code), whereas others do. However, in general, you need to redirect the output and stderr handles (e.g. to a pipe if doing it under Linux, but a file would do as well) and read them from the remaining program. As an example, TProcess (in unit Process) provides means for all of this.

Tomas

Can you compile the crashing program with  -gl    ?

That should give you a useful stack dump with line numbers.

Am Freitag, 1. September 2023, 17:57:26 CEST schrieb Tomas Hajny via fpc- pascal:

Look above.

> I start the program with a console command.

More precisely: I start the crashing program with a shell command from the remaining program.

Everything runs as root. These are more or less the only programs on this (mini-itx embedded) computer running. I have full control then.

If I start the program with

program 2>output.txt

it works! Thank you.

Peter B wrote

Can you compile the crashing program with -gl ?

Yes, I can. I know this, but then the program is bigger. For finding the error it is useful, yes. Otherwise I switch it off. There are around 100 clients that download the program automatically.

That should give you a useful stack dump with line numbers.

:-)