acosh

Section: C Library Functions (3)
Updated: 2023-02-05
Index Return to Main Contents
 

NAME

acosh, acoshf, acoshl - inverse hyperbolic cosine function  

LIBRARY

Math library (libm, -lm)  

SYNOPSIS

#include <math.h>

double acosh(double x);
float acoshf(float x);
long double acoshl(long double x);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

acosh(): 

    _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
        || _XOPEN_SOURCE >= 500
        || /* Since glibc 2.19: */ _DEFAULT_SOURCE
        || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE

acoshf(), acoshl(): 

    _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
        || /* Since glibc 2.19: */ _DEFAULT_SOURCE
        || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
 

DESCRIPTION

These functions calculate the inverse hyperbolic cosine of x; that is the value whose hyperbolic cosine is x.  

RETURN VALUE

On success, these functions return the inverse hyperbolic cosine of x.

If x is a NaN, a NaN is returned.

If x is +1, +0 is returned.

If x is positive infinity, positive infinity is returned.

If x is less than 1, a domain error occurs, and the functions return a NaN.  

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 less than 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).
InterfaceAttributeValue
acosh(), acoshf(), acoshl() Thread safetyMT-Safe

 

STANDARDS

C99, POSIX.1-2001, POSIX.1-2008.

The variant returning double also conforms to SVr4, 4.3BSD.  

SEE ALSO

asinh(3), atanh(3), cacosh(3), cosh(3), sinh(3), tanh(3)

 

Index

NAME
LIBRARY
SYNOPSIS
DESCRIPTION
RETURN VALUE
ERRORS
ATTRIBUTES
STANDARDS
SEE ALSO
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Time: 11:28:34 GMT, April 19, 2024