al_fixsqrt - Allegro 5 API

       This  finds  out the non negative square root of x.  If x is negative, Allegro’s errno is set to EDOM and
       the function returns zero.

Allegro reference manual                                                                     al_fixsqrt(3alleg5)

       al_fixsqrt - Allegro 5 API

              #include <allegro5/allegro.h>

              al_fixed al_fixsqrt(al_fixed x)