# cosh(3) — Linux manual page

```cosh(3)                 Library Functions Manual                 cosh(3)
```

## NAME         top

```       cosh, coshf, coshl - hyperbolic cosine function
```

## LIBRARY         top

```       Math library (libm, -lm)
```

## SYNOPSIS         top

```       #include <math.h>

double cosh(double x);
float coshf(float x);
long double coshl(long double x);

Feature Test Macro Requirements for glibc (see
feature_test_macros(7)):

coshf(), coshl():
_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
|| /* Since glibc 2.19: */ _DEFAULT_SOURCE
|| /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
```

## DESCRIPTION         top

```       These functions return the hyperbolic cosine of x, which is
defined mathematically as:

cosh(x) = (exp(x) + exp(-x)) / 2
```

## RETURN VALUE         top

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

If x is a NaN, a NaN is returned.

If x is +0 or -0, 1 is returned.

If x is positive infinity or negative infinity, positive infinity
is returned.

If the result overflows, a range error occurs, and the functions
return +HUGE_VAL, +HUGE_VALF, or +HUGE_VALL, respectively.
```

## ERRORS         top

```       See math_error(7) for information on how to determine whether an
error has occurred when calling these functions.

The following errors can occur:

Range error: result overflow
errno is set to ERANGE.  An overflow floating-point
exception (FE_OVERFLOW) is raised.
```

## ATTRIBUTES         top

```       For an explanation of the terms used in this section, see
attributes(7).
┌─────────────────────────────────────┬───────────────┬─────────┐
│ Interface                           │ Attribute     │ Value   │
├─────────────────────────────────────┼───────────────┼─────────┤
│ cosh(), coshf(), coshl()            │ Thread safety │ MT-Safe │
└─────────────────────────────────────┴───────────────┴─────────┘
```

## STANDARDS         top

```       C11, POSIX.1-2008.
```

## HISTORY         top

```       C99, POSIX.1-2001.

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

## BUGS         top

```       In glibc 2.3.4 and earlier, an overflow floating-point
(FE_OVERFLOW) exception is not raised when an overflow occurs.
```

## SEE ALSO         top

```       acosh(3), asinh(3), atanh(3), ccos(3), sinh(3), tanh(3)

Linux man-pages (unreleased)     (date)                          cosh(3)
```

Pages that refer to this page: acosh(3)asinh(3)atanh(3)sinh(3)tanh(3)