fixacos (3) Linux Manual Page

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

Synopsis

#include <allegro.h>

fixed fixacos(fixed x);

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′.

See Also