---
name: "SDL_atan"
section: "3"
platform: "linux"
package: "libsdl3-doc"
version: "3.2.10+ds-1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/SDL_atan"
---

# SDL\_atan(3)

Compute the arc tangent of x .

## NAME

SDL\_atan - Compute the arc tangent of **x** .

## HEADER FILE

Defined in SDL3/SDL\_stdinc.h

## SYNOPSIS

```
#include "SDL3/SDL.h"
```

**double SDL\_atan(double x);**

## DESCRIPTION

The definition of **y**=**atan(x)** is **x**=**tan(y)** .

Domain: **-INF**\<=**x**\<=**INF** Range: **-Pi/2**\<=**y**\<=**Pi/2** This function operates on double-precision floating point values, use

**SDL\_atanf**\
  for single-precision floats.

To calculate the arc tangent of y / x, use  **SDL\_atan2** .

This function may use a different approximation across different versions, platforms and configurations. i.e, it can return a different value given the same input on different machines or operating systems, or if SDL is updated.

## FUNCTION PARAMETERS

- *x*

  floating point value.

## RETURN VALUE

Returns arc tangent of of **x** in radians, or 0 if **x**=**0** .

## THREAD SAFETY

It is safe to call this function from any thread.

## AVAILABILITY

This function is available since SDL 3.2.0.

## SEE ALSO

**•**(3), [**SDL\_atanf**(3)](/SDL_atanf/3.md), **•**(3), [**SDL\_atan2**(3)](/SDL_atan2/3.md), **•**(3), [**SDL\_tan**(3)](/SDL_tan/3.md)