CHN_2NDBUFSIZE_MIN
RANGE(maxsize, CHN_2NDBUFSIZE_MIN, CHN_2NDBUFSIZE_MAX);
if (max < CHN_2NDBUFSIZE_MIN)
max = CHN_2NDBUFSIZE_MIN;
b->align, CHN_2NDBUFSIZE_MIN);
CHN_2NDBUFSIZE_MIN, &hblksz, &hblkcnt);
CHN_2NDBUFSIZE_MIN);