COSH(3M) Mathematical Library Functions COSH(3M)

# 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:

 ATTRIBUTE TYPE ATTRIBUTE VALUE Interface Stability Standard MT-Level MT-Safe