Re: [bug-libsigsegv] libsigsegv

[Jonny Grant]

On 31/03/2019 22:43, Bruno Haible wrote:
> Jonny Grant wrote:
> > Would be good if there was a simple example and an example of the kind
> > of output we could expect. At the moment it just looks like test files.
>
> The files tests/sigsegv1.c and tests/stackoverflow1.c are simple
> fully working examples. Other than that, please refer to README and sigsegv.h.
>
> > Something with a backtrace of a SEGV would be handy..
>
> When there is a SIGSEGV, the gdb stack trace is most often inaccurate.
> The only reliable information that you get is
>    - the fault address,
>    - the information whether it's a stack overflow or not.
>
> Bruno

Hi!

Thank you for your reply Bruno! I had a look and tests/sigsegv1.c and 
tests/stackoverflow1.c seems to have SIGSEGV handlers, but doesn't offer 
a stack trace? I wrote the attached, it's pretty simple and outputs a 
little stack trace. I was just hoping for something a little more 
advanced than my addr2line wrapper! but at least I have something for 
the moment to use.

From my experience I've always been fortunate that stack trace is 
generally pretty accurate with gdb, maybe I've been lucky.

 ./exception5
Unhandled C++ exception: [vector::_M_range_check: __n (which is 0) >= 
this->size() (which is 0)]

Backtrace:
[0]: ./exception5(+0x108d) [0x557502de108d]
print_trace()
exception5.cpp:23

[1]: ./exception5(+0x1528) [0x557502de1528]
test()
exception5.cpp:107

[2]: ./exception5(+0x1548) [0x557502de1548]
main
exception5.cpp:128

[3]: /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xe7) 
[0x7f40815c0b97]

[4]: ./exception5(+0xf2a) [0x557502de0f2a]
_start
??:?
Segmentation fault (core dumped)


Cheers, Jonny

exception5.cpp
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