---
name: "SDL_acosf"
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_acosf"
---

# SDL\_acosf(3)

Compute the arc cosine of x .

## NAME

SDL\_acosf - Compute the arc cosine of **x** .

## HEADER FILE

Defined in SDL3/SDL\_stdinc.h

## SYNOPSIS

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

**float SDL\_acosf(float x);**

## DESCRIPTION

The definition of **y**=**acos(x)** is **x**=**cos(y)** .

Domain: **-1**\<=**x**\<=**1** Range: **0**\<=**y**\<=**Pi** This function operates on single-precision floating point values, use

**SDL\_acos**\
  for double-precision floats.

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 cosine of **x** , in radians.

## 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\_acos**(3)](/SDL_acos/3.md), **•**(3), [**SDL\_asinf**(3)](/SDL_asinf/3.md), **•**(3), [**SDL\_cosf**(3)](/SDL_cosf/3.md)