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.TH "al_fixacos" "3alleg5" "" "Allegro reference manual" ""
.hy
.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[R]
.fi
.SH DESCRIPTION
.PP
This function finds the inverse cosine of a value using a lookup table.
The input must be a fixed point value.
The inverse cosine is defined only in the domain from -1 to 1.
Outside of this input range, the function will set Allegro\[cq]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[R]
.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.