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From: j@bonnie.heep.sax.de (J Wunsch)
Newsgroups: comp.unix.bsd.freebsd.misc
Subject: Re: gdb debugger question (FreeBSD 2.0)
Date: 10 Jul 1995 09:50:41 +0200
Organization: Private U**x site, Dresden.
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References: <rjb-0807952240230001@palpk-s13.intac.com>
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Bob Badaracco <rjb@intac.com> wrote:
>I'm trying to debug a C program with the gdb debugger under FreeBSD. I don't
>have that much experience with this type of debugger and need some help.
>
>1. What compiler options do I need to turn on in order to generate a
>symbol table for the debugger to use?
-g
If you're using -g in company with -O or -O2 (which is possible for
the gcc), expect some bogus ``look & feel'' when single-stepping the
code due to the optimization. This is harmless, but sometimes
confusing.
>2. When my program dies, how can I get the debugger to stop where it happens?
Depends on how you define ``the program dies''. If it's receiving a
signal, the debugger will catch the signal before the program sees it
anyway. This is effectively the same as if you had inserted a
breakpoint just where the program failed. If your program is
voluntarily exiting due to a failure condition, it might help to set a
breakpoint at the function `exit', so you can trace back to the spot
where the program has been calling `exit'.
>Any useful documentation available anywhere for this?
The online help is already somewhat useful (try `help', or `help
<command>'). There used to be a large info file for gdb. You can
look at it by running the `info' command. Beware, the info in 2.0.5
does not yet understand arrow keys; you will have to use ^P and ^N to
move the cursor back and forth. I've been commiting a fix by Thomas
Gellekum for this recently.
--
cheers, J"org private: joerg_wunsch@uriah.heep.sax.de
http://www.sax.de/~joerg/
Never trust an operating system you don't have sources for. ;-)