-template<class F1, class F2>
-inline int os::call_scandir(int (*scandir)(const char *, struct dirent ***, F1, F2), const char *dir, struct dirent ***namelist, int(*filter)(const struct dirent *), int(*compar)(const void *, const void *))
+template<class _F1, class _F2>
+inline int os::call_scandir(int (*scandir)(const char *, struct dirent ***, _F1, _F2), const char *dir, struct dirent ***namelist, int(*filter)(const struct dirent *), int(*compar)(const void *, const void *))