ACOS(3) manual page
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acos, acosf, acosl - arc cosine function
#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
The acos() function calculates the arc cosine
of x; that is the value whose cosine is x.
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.
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.
C99, POSIX.1-2001. The variant returning double also conforms
to SVr4, 4.3BSD, C89.
asin(3)
, atan(3)
, atan2(3)
, cacos(3)
, cos(3)
,
sin(3)
, tan(3)
This page is part of release 3.78 of the Linux man-pages
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/man-pages/.
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