zerop (ANSI and GNU Common Lisp Document)

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#### 12.2.18 zerop [Function]

`zerop` number ⇒ generalized-boolean

#### Pronunciation::

pronounced ’z\=e (, )r\=o(, )p\=e

#### Arguments and Values::

number—a number.

generalized-boolean—a generalized boolean.

#### Description::

Returns true if number is zero (integer, float, or complex); otherwise, returns false.

Regardless of whether an implementation provides distinct representations for positive and negative floating-point zeros, `(zerop -0.0)` always returns true.

#### Examples::

     (zerop 0) ⇒  true
     (zerop 1) ⇒  false
     (zerop -0.0) ⇒  true
     (zerop 0/100) ⇒  true
     (zerop #c(0 0.0)) ⇒  true

#### Exceptional Situations::

Should signal an error of type type-error if number is not a number.

#### Notes::

     (zerop number) ≡ (= number 0)