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2.4.8.4 Sharpsign Asterisk

**Syntax:** `#*<<`*bits*`>>`

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.

**Syntax:** `#<<`*n*`>>*<<`*bits*`>>`

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 22.1.3.6 (Printing Bit Vectors).

The following X3J13 cleanup issue, *not part of the specification*, applies to this section:

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