problems catching std::runtime_error in a .so built with -fPIC

[Hasan Mahmood]

Sorry... this is a false alarm. Apparently, out in-house build tools
were adding -static-libgcc to linker line, which is causing the
problem. Taking away -static-libgcc fixes this.

Hasan.

On Wed, Apr 22, 2009 at 4:33 PM, Hasan Mahmood <hasan.mahm@gmail.com> wrote:
> I believe both of these are happening:
>
> hmahmood@...> g++ -fPIC -fexceptions -frtti -shared main.cpp -v
> Using built-in specs.
> Target: i586-suse-linux
> Configured with: ../configure --enable-threads=posix --prefix=/usr
> --with-local-prefix=/usr/local --infodir=/usr/share/info
> --mandir=/usr/share/man --libdir=/usr/lib --libexecdir=/usr/lib
> --enable-languages=c,c++,objc,fortran,obj-c++,java,ada
> --enable-checking=release
> --with-gxx-include-dir=/usr/include/c++/4.2.1 --enable-ssp
> --disable-libssp --disable-libgcj --with-slibdir=/lib
> --with-system-zlib --enable-shared --enable-_cxa_atexit
> --enable-libstdcxx-allocator=new --disable-libstdcxx-pch
> --program-suffix=-4.2 --enable-version-specific-runtime-libs --w
> ithout-system-libunwind --with-cpu=generic --host=i586-suse-linux
> Thread model: posix
> gcc version 4.2.1 (SUSE Linux)
>  /usr/lib/gcc/i586-suse-linux/4.2.1/cc1plus -quiet -v -D_GNU_SOURCE
> main.cpp -quiet -dumpbase main.cpp -mtune=generic -auxbase main
> -version -fPIC -fexceptions -frtti -o /tmp/ccBVxqAa.s
> #include "..." search starts here:
> #include <...> search starts here:
>  /usr/include/c++/4.2.1
>  /usr/include/c++/4.2.1/i586-suse-linux
>  /usr/include/c++/4.2.1/backward
>  /usr/local/include
>  /usr/lib/gcc/i586-suse-linux/4.2.1/include
>  /usr/lib/gcc/i586-suse-linux/4.2.1/../../../../i586-suse-linux/include
>  /usr/include
> End of search list.
> GNU C++ version 4.2.1 (SUSE Linux) (i586-suse-linux)
>        compiled by GNU C version 4.2.1 (SUSE Linux).
> GGC heuristics: --param ggc-min-expand=99 --param ggc-min-heapsize=129418
> Compiler executable checksum: 87d7be6f5d9de7847748ea6085e60774
>  /usr/lib/gcc/i586-suse-linux/4.2.1/../../../../i586-suse-linux/bin/as
> -V -Qy -o /tmp/ccoQIilQ.o /tmp/ccBVxqAa.s
> GNU assembler version 2.17.50 (i586-suse-linux) using BFD version (GNU
> Binutils) 2.17.50.20070726-14 (SUSE Linux)
>  /usr/lib/gcc/i586-suse-linux/4.2.1/collect2 --eh-frame-hdr -m
> elf_i386 -shared /usr/lib/gcc/i586-suse-linux/4.2.1/../../../crti.o
> /usr/lib/gcc/i586-suse-linux/4.2.1/crtbeginS.o
> -L/usr/lib/gcc/i586-suse-linux/4.2.1
> -L/usr/lib/gcc/i586-suse-linux/4.2.1
> -L/usr/lib/gcc/i586-suse-linux/4.2.1/../../../../i586-suse-linux/lib
> -L/usr/lib/gcc/i586-suse-linux/4.2.1/../../.. /tmp/ccoQIilQ.o -lstdc++
> -lm -lgcc_s -lc -lgcc_s /usr/lib/gcc/i586-suse-linux/4.2.1/crtendS.o
> /usr/lib/gcc/i586-suse-linux/4.2.1/../../../crtn.o
>
> hmahmood@...> ldd a.out
>        linux-gate.so.1 =>  (0xffffe000)
>        libstdc++.so.6 => /usr/lib/libstdc++.so.6 (0xb7ef1000)
>        libm.so.6 => /lib/libm.so.6 (0xb7ecc000)
>        libgcc_s.so.1 => /lib/libgcc_s.so.1 (0xb7ec0000)
>        libc.so.6 => /lib/libc.so.6 (0xb7d8d000)
>        /lib/ld-linux.so.2 (0x80000000)
>
> On Wed, Apr 22, 2009 at 4:19 PM, Ian Lance Taylor <iant@google.com> wrote:
>> Hasan Mahmood <hasan.mahm@gmail.com> writes:
>>
>>> I am having a problem trying to catch std::runtime_error (thrown from
>>> libstdc++) in a .so I built with -fPIC. If I build without -fPIC, I
>>> can catch the exception. Here is the code in the .so:
>>
>> What operating system are you using?
>>
>> What version of gcc are you using?
>>
>> What happens when the program does not work as you expect?
>>
>> In general you can only catch an exception thrown by a shared library if
>> you are using a shared libgcc or if you are using a linker which
>> supports the --eh-frame-hdr option.  So first confirm that one or the
>> other is the case.  Use ldd to see whether you are linking against a
>> shared libgcc (named libgccc_s).  Use -v when linking to see whether gcc
>> pases --eh-frame-hdr to the linker.
>>
>> Ian
>>
>