NAME¶

std::cosh,std::coshf,std::coshl - std::cosh,std::coshf,std::coshl

Synopsis¶

Defined in header <cmath>
float cosh ( float num );

double cosh ( double num ); (until C++23)

long double cosh ( long double num );
/* floating-point-type */ (since C++23)
cosh ( /* floating-point-type */ num ); (constexpr since C++26)
float coshf( float num ); (1) (2) (since C++11)
(constexpr since C++26)
long double coshl( long double num ); (3) (since C++11)
(constexpr since C++26)
Additional overloads (since C++11)
Defined in header <cmath>
template< class Integer > (A) (constexpr since C++26)
double cosh ( Integer num );

1-3) Computes the hyperbolic cosine of num.
The library provides overloads of std::cosh for all cv-unqualified floating-point
types as the type of the parameter.
(since C++23)

A) Additional overloads are provided for all integer types, which are (since C++11)
treated as double.

Parameters¶

num - floating-point or integer value

Return value¶

If no errors occur, the hyperbolic cosine of num (cosh(num), or

enum
+e-num
2

) is returned.

If a range error due to overflow occurs, +HUGE_VAL, +HUGE_VALF, or +HUGE_VALL is
returned.

Error handling¶

Errors are reported as specified in math_errhandling.

If the implementation supports IEEE floating-point arithmetic (IEC 60559),

* if the argument is ±0, 1 is returned.
* If the argument is ±∞, +∞ is returned.
* if the argument is NaN, NaN is returned.

Notes¶

For the IEEE-compatible type double, if |num| > 710.5, then std::cosh(num)
overflows.

The additional overloads are not required to be provided exactly as (A). They only
need to be sufficient to ensure that for their argument num of integer type,
std::cosh(num) has the same effect as std::cosh(static_cast<double>(num)).

Example¶

// Run this code

#include <cerrno>
#include <cfenv>
#include <cmath>
#include <cstring>
#include <iostream>
// #pragma STDC FENV_ACCESS ON

int main()
{
const double x = 42;

std::cout << "cosh(1) = " << std::cosh(1) << '\n'
<< "cosh(-1) = " << std::cosh(-1) << '\n'
<< "log(sinh(" << x << ")+cosh(" << x << ")) = "
<< std::log(std::sinh(x) + std::cosh(x)) << '\n';

// special values
std::cout << "cosh(+0) = " << std::cosh(0.0) << '\n'
<< "cosh(-0) = " << std::cosh(-0.0) << '\n';

// error handling
errno=0;
std::feclearexcept(FE_ALL_EXCEPT);

std::cout << "cosh(710.5) = " << std::cosh(710.5) << '\n';

if (errno == ERANGE)
std::cout << " errno == ERANGE: " << std::strerror(errno) << '\n';
if (std::fetestexcept(FE_OVERFLOW))
std::cout << " FE_OVERFLOW raised\n";
}

Possible output:¶

cosh(1) = 1.54308
cosh(-1) = 1.54308
log(sinh(42)+cosh(42)) = 42
cosh(+0) = 1
cosh(-0) = 1
cosh(710.5) = inf
errno == ERANGE: Numerical result out of range
FE_OVERFLOW raised

See also¶

sinh
sinhf computes hyperbolic sine (\({\small\sinh{x}}\)sinh(x))
sinhl (function)
(C++11)
(C++11)
tanh
tanhf computes hyperbolic tangent (\({\small\tanh{x}}\)tanh(x))
tanhl (function)
(C++11)
(C++11)
acosh
acoshf computes the inverse hyperbolic cosine
acoshl (\({\small\operatorname{arcosh}{x}}\)arcosh(x))
(C++11) (function)
(C++11)
(C++11)
computes hyperbolic cosine of a complex number
cosh(std::complex) (\({\small\cosh{z}}\)cosh(z))
(function template)
cosh(std::valarray) applies the function std::cosh to each element of valarray
(function template)
C documentation for
cosh