Re: not catching exceptions

[Ludovic Brenta <ludovic@ludovic-brenta.org>]

mark wrote on comp.lang.ada:
> I'm targeting some Ada95 at three different systems.  One is a host
> system running Linux, Intel based.  Exceptions are caught just fine.
> Another is a bare board with a PowerPC running Linux.  Exceptions are
> also trapped fine.  The third is a system running Linux but instead of
> using glibc it uses uclibc.  Exceptions are not caught.  All I get is an
> abort message (abort).  The configure information for this one is below-
>
>    $ ./powerpc-mpc8248-linux-uclibc-gcc -v
>    Using built-in specs.
>    Target: powerpc-mpc8248-linux-uclibc
>    Configured with: ../../configure --prefix=/opt/atc/cpp_userchain
>    /ppc8248-linux-toolchain --target=powerpc-mpc8248-linux-uclibc
>    --with-cpu=603 --host=i686-pc-linux-gnu --build=i686-pc-linux-gnu
>    --with-sysroot=/opt/atc/cpp_userchain/ppc8248-linux-toolchain/sysroot
>    --enable-shared --enable-threads=gnat --disable-tls
>    --disable__cxa_atexit --enable-languages=c,ada
>     Thread model: gnat
>     gcc version 4.1.2
>
> I've tried this with both --enable-threads (POSIX model) and
> enable-threads=gnat.  I've tried with --enable__cxa_atexit and
> --disable__cxa_atexit.  I can't seem to catch exceptions.
>
> A simple test program where I just raise and catch an exception gives
> the same result...abort.  Outside of not being able to catch exceptions,
> everything else works great (tasking, protected types, etc).
>
> Any thoughts on why exceptions are not being trapped on the  would be
> appreciated.
>
> Thanks.

I found this which may help:

http://gcc.gnu.org/ml/gcc/2007-07/msg00290.html

IIUC, you can enable exceptions on uClibc either by configuring the
cross-compiler to use the setjump/longjump (SJLJ) mechanism or by
patching uClibc to support zero-cost exceptions (ZCX).  It is possible
that a newer version of uClibc is available that handles ZCX, possibly
with some configuration.

If you have more trouble, I suggest you ask on the GCC mailing list as
your question is quite technical and not specific to Ada (exceptions
are handled by the GCC back-end which is common to all languages).

--
Ludovic Brenta.