---
name: "sisnan.f"
section: "3"
platform: "linux"
package: "lapack-doc"
version: "3.12.1-2"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/sisnan.f"
---

# sisnan.f(3)

## NAME

SRC/sisnan.f

## SYNOPSIS

### Functions/Subroutines

logical function **sisnan** (sin)\
 **SISNAN** tests input for NaN.

## Function/Subroutine Documentation

### logical function sisnan (real, intent(in) sin)

**SISNAN** tests input for NaN.

**Purpose:**

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

**Parameters**

*SIN*

```
!>          SIN is REAL
!>          Input to test for NaN.
!>
```

**Author**

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line **58** of file **sisnan.f**.

## Author

Generated automatically by Doxygen for LAPACK from the source code.