Provided by: allegro5-doc_5.2.7.0-1build1_all 

NAME
al_fixatan - Allegro 5 API
SYNOPSIS
#include <allegro5/allegro.h>
al_fixed al_fixatan(al_fixed x)
DESCRIPTION
This function finds the inverse tangent of a value using a lookup table. The input must be a fixed point
value. The inverse tangent is the value whose tangent is x.
Example:
al_fixed result;
/* Sets result to binary angle 13. */
result = al_fixatan(al_ftofix(0.326));
RETURN VALUE
Returns the inverse tangent of a fixed point value, measured as a fixed point binary format angle.
Allegro reference manual al_fixatan(3alleg5)