 acosl(3)  phpMan
ACOS(3) Linux Programmer's Manual ACOS(3)
NAME
acos, acosf, acosl  arc cosine function
SYNOPSIS
#include <math.h>
double acos(double x);
float acosf(float x);
long double acosl(long double x);
Link with lm.
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
acosf(), acosl():
_BSD_SOURCE  _SVID_SOURCE  _XOPEN_SOURCE >= 600  _ISOC99_SOURCE 
_POSIX_C_SOURCE >= 200112L;
or cc std=c99
DESCRIPTION
The acos() function calculates the arc cosine of x; that is the value whose cosine is x.
RETURN VALUE
On success, these functions return the arc cosine of x in radians; the return value is in
the range [0, pi].
If x is a NaN, a NaN is returned.
If x is +1, +0 is returned.
If x is positive infinity or negative infinity, a domain error occurs, and a NaN is
returned.
If x is outside the range [1, 1], a domain error occurs, and a NaN is returned.
ERRORS
See math_error(7) for information on how to determine whether an error has occurred when
calling these functions.
The following errors can occur:
Domain error: x is outside the range [1, 1]
errno is set to EDOM. An invalid floatingpoint exception (FE_INVALID) is raised.
CONFORMING TO
C99, POSIX.12001. The variant returning double also conforms to SVr4, 4.3BSD, C89.
SEE ALSO
asin(3), atan(3), atan2(3), cacos(3), cos(3), sin(3), tan(3)
COLOPHON
This page is part of release 3.74 of the Linux manpages project. A description of the
project, information about reporting bugs, and the latest version of this page, can be
found at http://www.kernel.org/doc/manpages/.
20100920 ACOS(3)
