test

        std::cout << "[plugin] loading " << path << std::endl;

        void *handle = ::dlopen(path.c_str(), RTLD_NOW | RTLD_LOCAL);

        // RTLD_GLOBAL, not RTLD_LOCAL: IPlugin and its extension-point interfaces (see

        // PluginApi.h) have no out-of-line virtual function, so their vtable/typeinfo get

        // vague (weak) linkage rather than one strong definition. Under RTLD_LOCAL every

        // dlopen'd plugin -- and the host binary -- carries its own private copy, and

        // dynamic_cast (used by collect<Iface>() below) compares typeinfo identity across

        // images and finds no match, even though the plugin genuinely implements the

        // interface (virtual calls still work fine since those go through the vtable

        // pointer directly, not RTTI). RTLD_GLOBAL lets the dynamic linker share one copy

        // of those weak symbols across the whole process instead.

        void *handle = ::dlopen(path.c_str(), RTLD_NOW | RTLD_GLOBAL);

        if (!handle) {

            std::cerr << "[plugin] " << fname << ": dlopen failed: " << (::dlerror() ? ::dlerror() : "unknown error") << std::endl;