acosl (3)
Leading comments
Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
and Copyright 2008, Linux Foundation, written by Michael Kerrisk
<mtk.manpages@gmail.com>
%%%LICENSE_START(VERBATIM)
Permission is granted to make and distribute verbatim copies of this
manual provided the copyright notice and this permission notice are
preserved on all copies.
Permission is granted to copy and distribute modified versions of this
manual under the conditions for verbatim copying, provided that the
entire resulting ...
NAME
acos, acosf, acosl - arc cosine functionSYNOPSIS
#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
These functions calculate 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.
ATTRIBUTES
For an explanation of the terms used in this section, see attributes(7).| Interface | Attribute | Value |
| acos(), acosf(), acosl() | Thread safety | MT-Safe |
CONFORMING TO
C99, POSIX.1-2001, POSIX.1-2008.The variant returning double also conforms to SVr4, 4.3BSD, C89.