LONG_PER_U64
.keylen = LONG_PER_U64,
.no_pairs = NODESIZE / sizeof(long) / (1 + LONG_PER_U64),
.no_longs = LONG_PER_U64 * (NODESIZE / sizeof(long) / (1 + LONG_PER_U64)),
.keylen = 2 * LONG_PER_U64,
.no_pairs = NODESIZE / sizeof(long) / (1 + 2 * LONG_PER_U64),
.no_longs = 2 * LONG_PER_U64 * (NODESIZE / sizeof(long) / (1 + 2 * LONG_PER_U64)),
#define MAX_KEYLEN (2 * LONG_PER_U64)