__NFD_BYTES
char *newfdset = realloc(fds->fdset, __NFD_BYTES(fd));
memset(newfdset + __NFD_BYTES(fds->fdsize), 0,
__NFD_BYTES(fd) - __NFD_BYTES(fds->fdsize));
fd_set *copy = calloc(1, __NFD_BYTES(size));
memcpy(copy, orig, __NFD_BYTES(size));
memcpy(readfds, svc_fdset_get(), __NFD_BYTES(fdsize));