dlsym multiple defintion about dlfcn-win32

[pali]

Probably you need to mark your __cxa_throw implementation with __declspec(dllexport).

Then main problem is that symbols on PE targets are resolved at compile/link time. So once you link symbol A in your executable B with library C then always this combination would be used.

RTLD_NEXT is locating symbol in executable at runtime. So to make it working, you need to have loaded one symbol name more times.

As __cxa_throw is in libstdc++.a you have to avoid using libstdc++ at compile/link time if you want to use your __cxa_throw implementation. But I guess you cannot avoid it as you want to use C++.

Anyway, I'm not sure if you can use dlsym/RTLD_NEXT for static linked libraries. I think it needs working with dynamic DLL libraries. And this probably applies also for ELF targets. On Linux it is working because you are for sure linking std library dynamically.

[pali]

dlsym/dlfcn is for dynamic linked code/libraries. Nott for static linked .a libraries. So in above setup with static linked libstdc++.a library, dlsym would not work.