A simple bit vector is constructed containing the indicated bits (0's and 1's), where the leftmost bit has index zero and the subsequent bits have increasing indices.
With an argument n, the vector to be created is of length n. If the number of bits is less than n but greater than zero, the last bit is used to fill all remaining bits of the bit vector.
The notations #* and #0* each denote an empty bit vector.
Regardless of whether the optional numeric argument n is provided, the token that follows the asterisk is delimited by a normal token delimiter. However, (unless the value of *read-suppress* is true) an error of type reader-error is signaled if that token is not composed entirely of 0's and 1's, or if n was supplied and the token is composed of more than n bits, or if n is greater than one, but no bits were specified. Neither a single escape nor a multiple escape is permitted in this token.
For information on how the Lisp printer prints bit vectors, see Section 220.127.116.11 (Printing Bit Vectors).
18.104.22.168.1 Examples of Sharpsign Asterisk