### Table of Contents

# cosh

## NAME

cosh, coshf, coshl - hyperbolic cosine function

## SYNOPSIS

c99 [ *flag*… ] *file*… **-lm** [ *library*… ]

#include <math.h>

**double cosh**(**double** *x*);

**float coshf**(**float** *x*);

**long double coshl**(**long double** *x*);

## DESCRIPTION

These functions compute the hyperbolic cosine of their argument *x*.

## RETURN VALUES

Upon successful completion, these functions return the hyperbolic cosine of *x*.

If the correct value would cause overflow, a range error occurs and **cosh()**, **coshf()**, and **coshl()** return the value of the macro **HUGE_VAL**, **HUGE_VALF**, and **HUGE_VALL**, respectively.

If *x* is NaN, a NaN is returned.

If *x* is ±0, 1.0 is returned.

If *x* is ±Inf, ±Inf is returned.

For exceptional cases, **matherr**(3M) tabulates the values to be returned by **cosh()** as specified by SVID3 and XPG3.

## ERRORS

These functions will fail if:

**Range Error**

The result would cause an overflow.

If the integer expression (**math_errhandling** & **MATH_ERREXCEPT**) is non-zero, the overflow floating-point exception is raised.

The **cosh()** function sets **errno** to **ERANGE** if the result would cause an overflow.

## USAGE

An application wanting to check for exceptions should call **feclearexcept**(**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 **cosh()**. On return, if **errno** is non-zero, an error has occurred. The **coshf()** and **coshl()** functions do not set **errno**.

## ATTRIBUTES

See attributes(7) for descriptions of the following attributes:

## SEE ALSO

**math.h**(3HEAD), **acosh**(3M), **feclearexcept**(3M), **fetestexcept**(3M), **isnan**(3M), **matherr**(3M), **sinh**(3M), **tanh**(3M), attributes(7), standards(7)