al_fixacos(3)

✨ NAME ✨

okay so bestie, we're on the al_fixacos page — it's part of the Allegro 5 API — and the manual name is Library Functions Manual, which I'm folding in right here instead of copying the header line like a bot 🫶.

🌸 SYNOPSIS 🌸

#include <allegro5/allegro.h>

al_fixed al_fixacos(al_fixed x);

🎀 DESCRIPTION 🎀

So al_fixacos finds the inverse cosine of a value using a lookup table. The input must be a fixed point value, no cap.

The inverse cosine is defined only in the domain from -1 to 1. Outside of this input range, the function will set Allegro’s errno to EDOM and return zero. That's the vibe check: out-of-range input gets EDOM plus zero 😭.

Example:

al_fixed result;

/* Sets result to binary angle 128. */
result = al_fixacos(al_itofix(-1));

🔥 RETURN VALUE 🔥

Returns the inverse sine of a fixed point value — and yes, bestie, the page literally says inverse sine here, I'm reading it exactly and not editing it 💀 — measured as fixed point binary format angle, or zero if the input was out of range. All return values of this function will be in the range 0 to 128. Periodt.

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that's the whole page, bestie — go off and cosine responsibly 💅

Source/version: Allegro reference manual, page al_fixacos(3). Date: not listed in the footer, so I'm not making one up 🌸.