Provided by: allegro4-doc_4.4.2-4_all

**NAME**

fixacos - Fixed point inverse cosine lookup table. Allegro game programming library.

**SYNOPSIS**

#include<allegro.h>fixedfixacos(fixedx);

**DESCRIPTION**

This function finds the inverse cosine of a value using a lookup table. The input value must be a fixed point radian. The inverse cosine is defined only in the domain from `-1' to `1'. Outside of this input range, the function will set `errno' to EDOM and return zero. Example: fixed result; /* Sets `result' to binary angle 128. */ result = fixacos(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'.