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Date: Wed, 2 Dec 2009 08:37:15 -0500
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Subject: Re: odd segfault with my c program using cygwin 1.7
From: mike marchywka <marchywka AT gmail DOT com>
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On 12/2/09, jeffunit <jeff AT jeffunit DOT com> wrote:
>
>   Still, it could be some other overflow somewhere else; as I'd guess you
> were
> reasoning, that's the commonest reason for this sort of bug that crops up on
> some platforms with some stack and memory layouts and not others.
>
>    Jeff, recompile your code, adding the "-g" flag, then run it under gdb,
> and
> when the segfault happens, use the "bt" command to get a backtrace and see
> where you are.
>
>      cheers,
>        DaveK
>
> It runs correctly under the debugger, without core dump.
> I am 99.9% sure the bug is outside my program. As I said,
> I have run it successfully with cygwin 1.5, and linux.
>
> I cannot imagine commenting/uncommenting the print statement
> changing the program execution. I suspect a library resource
> issue causing the segfault.
>

Memory corruption is tricky, right up there with threading problems.
This loop seems pretty self contained, what else are you doing prior
to that? An investigation along these lines doesn't rule out a library
problem but does help find more possibilities. Somtimes linking
with bad libs can cause odd behaviours- have you tried to catch
the fault? I found a build problem by an inability to catch "anything."

> As others have pointed out, I am pretty sure it is not going
> out of bounds on the array.
>
> thanks,
> jeff
>
>
>
>
>
>
>
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