rem: if (len < 0) exit_cleanup(1);
add: if (len < 0) exit_cleanup(RERR_STREAMIO);
context: void io_printf(int fd, const char *format, ...){	va_list ap;  	char buf[1024];	int len;		va_start(ap, format);	len = vslprintf(buf, sizeof(buf)-1, format, ap);	va_end(ap);	if (len < 0) exit_cleanup(1);	write_sbuf(fd, buf);}