Simplified Common Lisp reference

Symbol class: Mathematics, Arithmetics, Logic and Comparisons

Syntax:

Symbol type: function

zeropnumber => boolean

Argument description:

number

a number

ZEROP function returns true if the argument is zero.

(zerop 0) => T
(zerop -0.0) => T
(zerop #c(0 0.0)) => T
(zerop #c(0 0.1)) => NIL
(zerop 3/3) => NIL