---
name: "sisnan"
section: "3lapack"
platform: "linux"
package: "liblapack-doc"
version: "3.2.1-8"
release: "Debian 6.0 (Squeeze)"
platforms: ["linux"]
url: "https://new.carta.tech/sisnan/3lapack"
---

# sisnan(3lapack)

returns .TRUE

## NAME

SISNAN - returns .TRUE

## SYNOPSIS

- LOGICAL FUNCTION

  SISNAN(SIN)

- REAL

  SIN

## PURPOSE

SISNAN returns .TRUE. if its argument is NaN, and .FALSE. otherwise.  To be replaced by the Fortran 2003 intrinsic in the future.\

## ARGUMENTS

- SIN (input) REAL

  Input to test for NaN.