Re: C++ exceptions

[vijay nag <vijunag@gmail.com>]

On Wed, Nov 20, 2013 at 11:28 PM, Jonathan Wakely <jwakely.gcc@gmail.com> wrote:
> On 20 November 2013 17:43, vijay nag wrote:
>>
>> Nope Im running a variant of debian linux i686 kernel. Does GCC pick
>> libgcc from GCC_EXEC_PREFIX ?  I am running the program in complete
>> chroot encironment so that libraries donot collide with host machine.
>> Are you telling me that Issue is because of wrong version of libgcc ?
>
> It's not possible to say, because you've still provided almost no
> information.  How are you building the libraries? What flags are you
> using to compile and link?
>
> Is the exception thrown from one of the libraries? Is the catch in a
> library or the main program?
>
> Have you tried a simple example that just has a single function in a
> single shared library that throws an exception?  If not, why not?
>
> Without most of this information we're just guessing randomly what the
> problem might be.

I tried creating a small binary to demonstrate the problem that I had
been facing with my gcc-4.7.2 tool chain and glibc-2.17. The library
and binaries were created using exact CFLAGS, CXXFLAGS et al.
Strangely, the problem doesn't manifest in my example program :(.  On
further hacking and debugging libgcc, I found that
_Unwind_RaiseException() was always "returning" in failure case with
return code _URC_END_OF_STACK.  Does it mean that FDE is missing for
the function which is suppose to catch the exception ? How do I check
if an FDE exists for a particular function or not ?

"Wait, are you throwing from a destructor? Those are noexcept by
default nowadays, which would cause a call to std::terminate. Specify
noexcept(false) on it if you insist."

>>> I don't think Im throwing exception from a destructor and by the way Try/Catch is not working even for POD types.