Date: Mon, 2 Nov 2009 16:42:12 +0100 From: Alexey Shuvaev <shuvaev@physik.uni-wuerzburg.de> To: Max Boyarov <m.boyarov@gmail.com> Cc: freebsd-hackers@freebsd.org Subject: Re: strange gdb behavior Message-ID: <20091102154212.GA30365@wep4035.physik.uni-wuerzburg.de> In-Reply-To: <87c7bb540911020552x4a602732pd2caecb17c8c4535@mail.gmail.com> References: <87c7bb540911020552x4a602732pd2caecb17c8c4535@mail.gmail.com>
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On Mon, Nov 02, 2009 at 03:52:33PM +0200, Max Boyarov wrote:
> Hi,
>
> Who could help understand this:
>
> `--> cat 1.c
> int
> main(int argc, char **argv)
> {
> return 0;
> }
>
> [snip]
>
> (gdb) set args test
> (gdb) b main
> Breakpoint 1 at 0x80483d0: file 1.c, line 3.
> (gdb) r
> Starting program: /tmp/1 test
>
> Breakpoint 1, main () at 1.c:3
> 3 {
> (gdb) print argc
> Error accessing memory address 0x0: Bad address.
> (gdb) list
> 1 int
> 2 main(int argc, char **argv)
> 3 {
> 4 return 0;
> 5 }
>
> checked on 9.0-CURRENT, 8.0-BETA3
>
On
FreeBSD wep4035 9.0-CURRENT FreeBSD 9.0-CURRENT #0 r198671: Fri Oct 30 16:12:10 CET 2009 root@wep4035:/usr/obj/usr/src/sys/GENERIC amd64
I have the following:
(gdb) set args test
(gdb) b main
Breakpoint 1 at 0x40052b: file 1.c, line 4.
(gdb) r
Starting program: /home/lexx/1 test
Breakpoint 1, main (argc=2, argv=0x7fffffffe790) at 1.c:4
4 return 0;
(gdb) list
1 int
2 main(int argc, char **argv)
3 {
4 return 0;
5 }
(gdb) print argc
$1 = 2
(gdb)
Note that the breakpoint is set to line 4, not line 3 as in your case.
There was a series of changes to the linker recently. Update to the latest
CURRENT might help.
HTH,
Alexey.
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