gcc5.2 abi change -> compatibility guaranteed? - c++

Question

I have the following situation (Ubuntu 15.10 and Debian Testing)
I have Lib A which is compiled without cxx11 and a lib B that uses -std=c++11. B includes and links against A, A uses boost.
If i link B to A, the application a A created crashes during dynload.
If i compile A without cxx11 or B with cxx11 everything works fine.
My question: as far i understood the ABI namespace add on should guarantee shuch kind of problem. Am i wrong here?
I created a example project to clarify the problem:
https://github.com/goldhoorn/sandbox/tree/gcc5.2-issue
test1 failed, the other tests passing.
GDB tells me:
Program received signal SIGSEGV, Segmentation fault.
0x00007ffff7bceb2e in _GLOBAL__sub_I_Lib.cpp () from ./libmyLib.so
(gdb) bt
#0 0x00007ffff7bceb2e in _GLOBAL__sub_I_Lib.cpp () from ./libmyLib.so
#1 0x00007ffff7deaa0a in call_init (l=<optimized out>, argc=argc#entry=1,
argv=argv#entry=0x7fffffffe688, env=env#entry=0x7fffffffe698)
at dl-init.c:78
#2 0x00007ffff7deaaf3 in call_init (env=0x7fffffffe698, argv=0x7fffffffe688,
argc=1, l=<optimized out>) at dl-init.c:36
#3 _dl_init (main_map=0x7ffff7ffe1a8, argc=1, argv=0x7fffffffe688,
env=0x7fffffffe698) at dl-init.c:126
#4 0x00007ffff7ddd1ca in _dl_start_user () from /lib64/ld-linux-x86-64.so.2
#5 0x0000000000000001 in ?? ()
#6 0x00007fffffffe89f in ?? ()
#7 0x0000000000000000 in ?? ()
Result from Valgrind:
goldhoorn#debian:/tmp/example$ LD_LIBRARY_PATH=. valgrind --show-below-main=yes ./main
==17140== Memcheck, a memory error detector
==17140== Copyright (C) 2002-2015, and GNU GPL'd, by Julian Seward et al.
==17140== Using Valgrind-3.11.0 and LibVEX; rerun with -h for copyright info
==17140== Command: ./main
==17140==
==17140==
==17140== Process terminating with default action of signal 11 (SIGSEGV)
==17140== Bad permissions for mapped region at address 0x401FE8
==17140== at 0x4E3EB2E: _GLOBAL__sub_I_Lib.cpp (in /tmp/example/libmyLib.so)
==17140== by 0x400EA09: call_init.part.0 (dl-init.c:78)
==17140== by 0x400EAF2: call_init (dl-init.c:36)
==17140== by 0x400EAF2: _dl_init (dl-init.c:126)
==17140== by 0x40011C9: ??? (in /lib/x86_64-linux-gnu/ld-2.19.so)
==17140==
==17140== HEAP SUMMARY:
==17140== in use at exit: 72,704 bytes in 1 blocks
==17140== total heap usage: 1 allocs, 0 frees, 72,704 bytes allocated
==17140==
==17140== LEAK SUMMARY:
==17140== definitely lost: 0 bytes in 0 blocks
==17140== indirectly lost: 0 bytes in 0 blocks
==17140== possibly lost: 0 bytes in 0 blocks
==17140== still reachable: 72,704 bytes in 1 blocks
==17140== suppressed: 0 bytes in 0 blocks
==17140== Rerun with --leak-check=full to see details of leaked memory
==17140==
==17140== For counts of detected and suppressed errors, rerun with: -v
==17140== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)
Segmentation fault

Answer 1

Please check your library A against the list of Cxx11 ABI backward incompatibilities: https://gcc.gnu.org/wiki/Cxx11AbiCompatibility
The C++98 language is ABI-compatible with the C++11 language, but several places in the library break compatibility. This makes it dangerous to link C++98 objects with C++11 objects.