INITIAL_SIZE
f._bf._base = f._p = malloc(INITIAL_SIZE);
f._bf._size = f._w = INITIAL_SIZE - 1; /* leave room for the NUL */
if (ret + 1 > INITIAL_SIZE && ret + 1 < pgsz / 2) {
f._bf._base = f._p = malloc(INITIAL_SIZE);
f._bf._size = f._w = INITIAL_SIZE - 1; /* leave room for the NUL */
if (ret + 1 > INITIAL_SIZE && ret + 1 < pgsz / 2) {