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ACOS(3) | Linux Programmer's Manual | ACOS(3) |
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():
_ISOC99_SOURCE ||
_POSIX_C_SOURCE >= 200112L
|| /* Since glibc 2.19: */ _DEFAULT_SOURCE
|| /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
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.
SEE ALSO¶
asin(3), atan(3), atan2(3), cacos(3), cos(3), sin(3), tan(3)COLOPHON¶
This page is part of release 4.16 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 https://www.kernel.org/doc/man-pages/.2017-09-15 |