al_fixacos(3)                                                    al_fixacos(3)

NAME
       al_fixacos - Allegro 5 API

SYNOPSIS

              #include <allegro5/allegro.h>

              al_fixed al_fixacos(al_fixed x);


DESCRIPTION
       This function finds the inverse cosine of a value using a lookup table.
       The input must be a fixed point value.  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.

       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, 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.

Allegro reference manual                                         al_fixacos(3)