Mark GetProcAddress Using In Win & Unix

typedef std::string (*foo_t)(const std::string);foo_t foo = NULL;...# ifdef _WIN32  HMODULE hDLL = ::LoadLibrary(szMyLib);  if (!hDll) { /*error*/ }  foo = (foo_t)::GetProcAddress(hDLL, "foo");# else  void *pLib = ::dlopen(szMyLib, RTLD_LAZY);  if (!pLib) { /*error*/ }  foo = (foo_t)::dlsym(pLib, "foo");# endif  if (!foo) { /*error*/ }  ...  foo("bar");  ...# ifdef _WIN32  ::FreeLibrary(hDLL);# else  ::dlclose(pLib);# endif