std::acosh, std::acoshf, std::acoshl

Since C++26

Header: <cmath>

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

# Declarations

float acosh ( float num );
double acosh ( double num );
long double acosh ( long double num );

(until C++23)

/*floating-point-type*/
acosh ( /*floating-point-type*/ num );

(since C++23) (constexpr since C++26)

float acoshf( float num );

(since C++11) (constexpr since C++26)

long double acoshl( long double num );

(since C++11) (constexpr since C++26)

SIMD overload (since C++26)

template< /*math-floating-point*/ V >
constexpr /*deduced-simd-t*/<V>
acosh ( const V& v_num );

(since C++26)

Additional overloads (since C++11)

template< class Integer >
double acosh ( Integer num );

(constexpr since C++26)

# Parameters

# Return value

If no errors occur, the inverse hyperbolic cosine of num (cosh-1(num), or arcosh(num)) on the interval [0, +∞], is returned.

# Notes

Although the C standard (to which C++ refers for this function) names this function “arc hyperbolic cosine”, the inverse functions of the hyperbolic functions are the area functions. Their argument is the area of a hyperbolic sector, not an arc. The correct name is “inverse hyperbolic cosine” (used by POSIX) or “area hyperbolic cosine”.

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::acosh(num) has the same effect as std::acosh(static_cast(num)).

# See also