How to configure Lazarus to avoid External: SIGSEGV
lazarus / 12-Debugger

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stab · 2010-05-19 14:20

Hi,

Made the most simple Lazarus app, just an empty form.
With no debugger it runs OK.
Running with GNU debugger (gdb) it does nothing but shows
immediately:
Project project1 raised exception class 'External: SIGSEGV'.

Lazarus version: 0.9.28.2 beta
FPC version:      2.2.4
SVN version;      22279

OS:                  Windows XP professional sp 3

What settings do I need to be able to use the debugger and
add breakpoints as in Delphi?

Regards
Staffan

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Martin_fr · 2010-05-19 14:42

There are many reasons outside Lazarus/gsb that can be part of this.

Search the forum for SigSegV

see this one
http://www.lazarus.freepascal.org/index.php/topic,6225.0.html

Otherwise some of the known issues:
- Some AntiVirus solutions don't like gdb. You may have to partly or
fully disable them.
I know from my own experience that BitDefender crashes any attempt to
debug, unless you disable certain features; Bitdefender's exception-
list for this feature seems to be a dummy configuration, as it doesn't
do anything / BitDefenders support stated about 6 month ago, that it
will be fixed in future (not yet).....
Other antivirus may be similar

- Try different versions of GDB, downloadable form mingw site.
Versions 6.8.3 and 7.0 and higher may sometimes help

- some people can start there exe the first time, but the 2nd and
further attempts fail => in this case: always reset the debugger (from
menu: "run")

Out of interest: Do you have any Microsoft IDE (Visual studio) or
similar installed ?

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stab · 2010-05-19 15:53

Thank you for your response.

Donwloaded gdb 7.1 but no luck, guess I have to rely on logfiles

Regards
Staffan

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picstart · 2010-05-19 16:18

If you don't need the latest release then 9.26.2 is very very stable
and won't I'll bet cause the issues you are seeing. Download 9.26.2 
while it is still available. 9.26.2 does 99.9% of what you will
probably need anyway.

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Martin_fr · 2010-05-19 18:06

Have you tried to hit F9 again when the sigsegv comes?
In some cases that let you continue your app.

I guess the stacktrace window isn't showing much...

what happens when you start gdb from a dos-box ("cmd")?

c:\path_to_gdb\gdb your_app.exe

then enter "r" followed by return

Does it also fail?
If so "bt" => does it give a backtrace?