SCM_PORT_BUFFER_AVAIL  385 ext/charconv/charconv.c     inroom = len = SCM_PORT_BUFFER_AVAIL(port);
SCM_PORT_BUFFER_AVAIL  477 src/port.c         int cursiz = SCM_PORT_BUFFER_AVAIL(p);
SCM_PORT_BUFFER_AVAIL  788 src/port.c         int datsiz = SCM_PORT_BUFFER_AVAIL(p);