How many memory the bit-vector using in sbcl?

Question

How many memory the bit-vector using in sbcl?

Does per bit spend 1 bit memory? Does per bit spend 1 byte memory? Does per bit spend 1 word memory?

Answer 1

Bit vectors in SBCL are stored efficiently with one bit per bit, plus some small housekeeping overhead per vector.

They are also very efficient at bitwise operations, working a full word at a time. For example, BIT-XOR on a 64-bit platform will work on 64 bits of a bit-vector at once.