On Tue, 29 Jun 2021, 05:58 Oleg Smolsky via Gcc-help, <gcc-help@xxxxxxxxxxx>
wrote:
> Hi, I've just hit a peculiar linking issue when using std::unordered_map,
> C++17 and mixing some shared libs built with GCC10/11. Here is the linking
> issue:
>
> test.o: In function `__gnu_cxx::new_allocator<std:
> :__detail::_Hash_node_base*>::allocate(unsigned long, void const*)':
> /opt/gcc-11/include/c++/11.1.0/ext/new_allocator.h:110: undefined reference
> to `std::__throw_bad_array_new_length()'
> collect2: error: ld returned 1 exit status
>
> The reproducer looks benign to me:
>
> struct Thing { int a, b, c; };
> int main(int argc, char **argv) {
> std::unordered_map<unsigned int, Thing *> map;
> map[1] = new Thing;
> }
>
> I hit the linking issue when the reproducer is built with GCC11 and I
> link libzmq.so.3 that was built with GCC10. This is all happening on a
> 64-bit Linux VM and I built both compilers on the same OS (Ubuntu 16). The
> issue goes away when I rebuild the 3rd-party lib with GCC11... yet I am
> failing to understand why this is happening... Is this an oversight in
> libstdc++ that results in an ABI break?
>
Are you using 'gcc' to link, not 'g++'?
