---
name: "ctanh"
section: "3"
platform: "linux"
package: "man-pages"
version: "6.19-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux", "freebsd"]
url: "https://new.carta.tech/ctanh"
---

# ctanh(3)

complex hyperbolic tangent

## NAME

ctanh, ctanhf, ctanhl - complex hyperbolic tangent

## LIBRARY

Math library (*libm*, *-lm*)

## SYNOPSIS

```
#include <complex.h>
```

**double complex ctanh(double complex** *z***);** **float complex ctanhf(float complex** *z***);** **long double complex ctanhl(long double complex** *z***);**

## DESCRIPTION

These functions calculate the complex hyperbolic tangent of *z*.

The complex hyperbolic tangent function is defined mathematically as:

```
ctanh(z) = csinh(z) / ccosh(z)
```

## ATTRIBUTES

For an explanation of the terms used in this section, see [**attributes**(7)](/attributes/7.md).

| | | |
| --- | --- | --- |
| **Interface** | **Attribute** | **Value** |
| **ctanh**(), **ctanhf**(), **ctanhl**() | Thread safety | MT-Safe |

## STANDARDS

C11, POSIX.1-2008.

## HISTORY

glibc 2.1. C99, POSIX.1-2001.

## SEE ALSO

[**cabs**(3)](/cabs/3.md), [**catanh**(3)](/catanh/3.md), [**ccosh**(3)](/ccosh/3.md), [**csinh**(3)](/csinh/3.md), [**complex**(7)](/complex/7.md)