std::asin, std::asinf, std::asinl

Since C++26

Header: <cmath>

1-3) Computes the principal value of the arc sine of num.The library provides overloads of std::asin for all cv-unqualified floating-point types as the type of the parameter.(since C++23)

# Declarations

float asin ( float num );
double asin ( double num );
long double asin ( long double num );

(until C++23)

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

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

float asinf( float num );

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

long double asinl( 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>
asin ( const V& v_num );

(since C++26)

Additional overloads (since C++11)

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

(constexpr since C++26)

# Parameters

# Return value

If a domain error occurs, an implementation-defined value is returned (NaN where supported).

# Notes

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

# Example

#include <cerrno>
#include <cfenv>
#include <cmath>
#include <cstring>
#include <iostream>
 
// #pragma STDC FENV_ACCESS ON
 
int main()
{
    std::cout << "asin(1.0) = " << asin(1) << '\n'
              << "2*asin(1.0) = " << 2 * asin(1) << '\n'
              << "asin(-0.5) = " << asin(-0.5) << '\n'
              << "6*asin(-0.5) =" << 6 * asin(-0.5) << '\n';
 
    // special values
    std::cout << "asin(0.0) = " << asin(0) << " asin(-0.0)=" << asin(-0.0) << '\n';
 
    // error handling
    errno = 0;
    std::feclearexcept(FE_ALL_EXCEPT);
 
    std::cout << "asin(1.1) = " << asin(1.1) << '\n';
 
    if (errno == EDOM)
        std::cout << "    errno == EDOM: " << std::strerror(errno) << '\n';
    if (std::fetestexcept(FE_INVALID))
        std::cout << "    FE_INVALID raised" << '\n';
}

# See also