On Mon, 16 Aug 2021 at 10:59, Florian Weimer wrote: > > * Jonathan Wakely via Gcc-help: > > > I'm not sure if GCC should change, or if the linker should be changed > > to permit a single non-weak non-UNIQUE definition to be merged with > > zero or more UNIQUE definitions. As a workaround you can compile the > > C++17 code with -fno-gnu-unique so that GCC uses a weak symbol, but > > that isn't a good solution in general (the unique binding exists for > > good reasons). > > What are those reasons, exactly? I think it was added to ensure uniqueness of static objects across libraries opened with RTLD_LOCAL. > I've been trying to find a rationale and specification of > STB_GNU_UNIQUE, but have not been successful. > > The glibc implementation does not handle symbol versions, it ignores > them. It's not entirely clear to me if this is a bug. Does anybody use it with more than one symbol version though? Using symbol versioning on a STB_GNU_UNIQUE symbol would seem to violate its uniqueness. > Furthermore, I haven't seen a case yet which would require > STB_GNU_UNIQUE and could not have been handled equally well via symbol > interposition. Does that work for RTLD_LOCAL though?
