acosh(3M) Mathematical Library Functions acosh(3M)NAME
acosh, acoshf, acoshl - inverse hyperbolic cosine functions
SYNOPSIS
c99 [ flag... ] file... -lm [ library... ]
#include <math.h>
double acosh(double x);
float acoshf(float x);
long double acoshl(long double x);
DESCRIPTION
These functions compute the inverse hyperbolic cosine of their argument
x.
RETURN VALUES
Upon successful completion, these functions return the inverse hyper‐
bolic cosine of their argument.
For finite values of x < 1, a domain error occurs and NaN is returned.
If x is NaN, NaN is returned.
If x is +1, +0 is returned.
If x is +Inf, +Inf is returned.
If x is −Inf, a domain error occurs and NaN is returned.
For exceptional cases, matherr(3M) tabulates the values to be returned
by acosh() as specified by SVID3 and XPG3.
ERRORS
These functions will fail if:
Domain Error The x argument is finite and less than 1.0, or is −Inf.
If the integer expression (math_errhandling &
MATH_ERREXCEPT) is non-zero, the invalid floating-point
exception is raised.
The acosh() function sets errno to EDOM if x is less
than 1.0.
USAGE
An application wanting to check for exceptions should call feclearex‐
cept(FE_ALL_EXCEPT) before calling these functions. On return, if
fetestexcept(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW) is
non-zero, an exception has been raised. An application should either
examine the return value or check the floating point exception flags to
detect exceptions.
An application can also set errno to 0 before calling acosh(). On
return, if errno is non-zero, an error has occurred. The acoshf() and
acoshl() functions do not set errno.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌─────────────────────────────┬─────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼─────────────────────────────┤
│Interface Stability │Standard │
├─────────────────────────────┼─────────────────────────────┤
│MT-Level │MT-Safe │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOcosh(3M), feclearexcept(3M), fetestexcept(3M), math.h(3HEAD), math‐
err(3M), attributes(5), standards(5)SunOS 5.11 12 Jul 2006 acosh(3M)