bitstr_size
(bitstr_t *)calloc((size_t)bitstr_size(nbits), sizeof(bitstr_t))
((name)[bitstr_size(nbits)])
#define _bitstr_size bitstr_size
bitstr_size(i++);
register int i = bitstr_size(n);
i, _bit_byte(i), _bit_mask(i), bitstr_size(i));
((name)[bitstr_size(nbits) / sizeof(ice_bitstr_t)])