.TH "al_fixacos(3alleg5) Allegro reference manual" "" "" "" ""
.SH NAME
.PP
al_fixacos \- Allegro 5 API
.SH SYNOPSIS
.IP
.nf
\f[C]
#include\ <allegro5/allegro.h>

al_fixed\ al_fixacos(al_fixed\ x);
\f[]
.fi
.SH DESCRIPTION
.PP
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 Allegro\[aq]s errno
to EDOM and return zero.
.PP
Example:
.IP
.nf
\f[C]
\ \ \ \ al_fixed\ result;

\ \ \ \ /*\ Sets\ result\ to\ binary\ angle\ 128.\ */
\ \ \ \ result\ =\ al_fixacos(al_itofix(\-1));
\f[]
.fi
.SH RETURN VALUE
.PP
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.