###### (This is the documentation for SDL3, which is under heavy development and the API is changing! [SDL2](https://wiki.libsdl.org/SDL2/) is the current stable version!) ## Draft **THIS PAGE IS A WORK IN PROGRESS** ... Please make edits to this page to improve it! # SDL_acos Use this function to compute arc cosine of `x`. ## Syntax ```c double SDL_acos(double x); ``` ## Function Parameters | | | | --------- | --------------------------------- | | **x** | floating point value, in radians. | ## Return Value Returns arc cosine of `x`. ## Remarks The definition of `y = acos(x)` is `x = cos(y)`. Domain: `-1 <= x <= 1` Range: `0 <= y <= Pi` ## Version This function is available since SDL 3.0.0. ## Code Examples ```c /* acos(x) = Pi/2 - asin(x) */ SDL_Log("acos(0):\t\t%f", SDL_acos(0)); SDL_Log("Pi/2 - asin(0):\t%f", M_PI / 2 - SDL_asin(0)); /* acos(-x) = Pi - acos(x) */ SDL_Log("acos(-(-1)):\t%f", SDL_acos(-(-1))); SDL_Log("Pi - acos(-1):\t%f", M_PI - SDL_acos(-1)); ``` ---- [CategoryAPI](CategoryAPI), [CategoryStandard](CategoryStandard), [CategoryDraft](CategoryDraft)