ACOS
ACOS
Section: Linux Programmer's Manual (3) Updated: 2010-09-20 Local index
Up
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 floating-point exception
(FE_INVALID )
is raised.
CONFORMING TO
C99, POSIX.1-2001.
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 3.27 of the Linux
man-pages
project.
A description of the project,
and information about reporting bugs,
can be found at
http://www.kernel.org/doc/man-pages/.

Index
NAME
SYNOPSIS
DESCRIPTION
RETURN VALUE
ERRORS
CONFORMING TO
SEE ALSO
COLOPHON
This document was created by
man2html ,
using the manual pages.
Time: 21:41:39 GMT, April 16, 2011