SM_IO_NOW
else if (mode == SM_IO_NOW)
mode != SM_IO_NOW) || (int) size < 0)
(void) sm_io_setvbuf(so->fp, SM_TIME_DEFAULT, NULL, SM_IO_NOW, 0);
(void) sm_io_setvbuf(so->fp, SM_TIME_DEFAULT, NULL, SM_IO_NOW, 0);