runtime  error Invalid class .
lazarus / 34-Windows

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aducom · 2022-02-27 20:23

I have a strange error, that does not occur on each machine. I created
an application with Lazarus. If I start it on a second laptop, then I
get the error 'Invalid class .' Press OK etc. Does someone have seen
this before, and is there some clue where to search for? It is running
fine on my development environment. It is not much info, but it is all
I have.

Thnx, Albert

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howardpc · 2022-02-27 21:04

Perhaps arising from a missing or corrupt .lfm file?

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SymbolicFrank · 2022-02-28 13:37

Perhaps you try to access a class from an external library or the OS,
and the .so or .DLL is missing?

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Martin_fr · 2022-02-28 14:16

Quote from: aducom on February 27, 2022, 09:23:02 pmI have a strange
error, that does not occur on each machine. I created an application
with Lazarus. If I start it on a second laptop, then I get the error
'Invalid class .' Press OK etc. Does someone have seen this before,
and is there some clue where to search for? It is running fine on my
development environment. It is not much info, but it is all I have.

You could copy gdb.exe on your laptop (where you get the error). You
should at least compile your app with line info -gl (but ideally debug
info: -gw )

Code: Text  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i gdb.exe
yourproject.exeb FPC_RAISEEXCEPTIONb FPC_RUNERRORr
If you hit FPC_RUNERROR => then there is no exception message (there
may be a subsequent exception). However, a FPC_RUNERROR means you
should be at the point of error that is of interrest. RunErrors should
not happen otherwise.

If you hit an FPC_RAISEEXCEPTION, you may want to check if it is the
one your are looking for. There may be other, expected exceptions that
will be caught and that you need to skip.
To continue your app when gdb paused it (e.g. if you are at an
unrelated exception:  c (and enter)

If you got the right exception, get a stacktrace: bt

To see the exception message (replace $rcx as needed):
- If you have full debug info:  x/s Exception($rcx).FMessage
  or sometimes:                    x/s ^Exception($rcx)^.FMessage
- If the above does not work: x/s ^^char(^^char($rcx)+1)^

Depending on your OS:
- On Win 64 use   $rcx
- On Linux 64 use $rdi
- On Win 32 use   $eax

If you can't get the exception message, just get the stacktrace, and
continue. You will then see, if the error message pops up, or if you
run into another exception later.

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aducom · 2022-02-28 21:01

Thanks for all hints. This was an odd issue, but it was an external
lib issue. After a reinstall of windows, it worked.