Arguments

Returns

t if the argument is not a number (nan), otherwise nil.

Description

This function tests to see whether the argument is a special floating point number that indicates the specific case of an illegal number or an infinite number. NAN is a floating point number that represents an invalid state, and is represented in Gamma as a constant. Please refer to Literals for more information on NAN.

Example

Gamma> isnan(sqrt(-1));
t
Gamma> isnan(sqrt(2));
nil