NAME

       al_fixatan2 - Allegro 5 API

SYNOPSIS

              #include <allegro5/allegro.h>

              al_fixed al_fixatan2(al_fixed y, al_fixed x)

DESCRIPTION

       This is a fixed point version of the libc atan2() routine.  It computes the arc tangent of
       y / x, but the signs of both arguments are used to determine the quadrant of  the  result,
       and  x  is permitted to be zero.  This function is useful to convert Cartesian coordinates
       to polar coordinates.

       Example:

                  al_fixed result;

                  /* Sets `result' to binary angle 64. */
                  result = al_fixatan2(al_itofix(1), 0);

                  /* Sets `result' to binary angle -109. */
                  result = al_fixatan2(al_itofix(-1), al_itofix(-2));

                  /* Fails the assert. */
                  result = al_fixatan2(0, 0);
                  assert(!al_get_errno());

RETURN VALUE

       Returns the arc tangent of y / x in fixed point binary format angle, from -128 to 128.  If
       both x and y are zero, returns zero and sets Allegro's errno to EDOM.