std::asin,std::asinf,std::asinl (3) - Linux Manuals

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

NAME

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

Synopsis

Defined in header <cmath>
float asin ( float arg );
float asinf( float arg ); (since C++11)
double asin ( double arg ); (1) (2)
long double asin ( long double arg );
long double asinl( long double arg ); (3) (since C++11)
double asin ( IntegralType arg ); (4) (since C++11)

1-3) Computes the principal value of the arc sine of arg.
4) A set of overloads or a function template accepting an argument of any integral_type. Equivalent to 2) (the argument is cast to double).

Parameters

arg - value of a floating-point or Integral_type

Return value

If no errors occur, the arc sine of arg (arcsin(arg)) in the range [-

π
2

, +

π
2

], is returned.
If a domain error occurs, an implementation-defined value is returned (NaN where supported)
If a range error occurs due to underflow, the correct result (after rounding) is returned.

Error handling

Errors are reported as specified in math_errhandling.
Domain error occurs if arg is outside the range [-1.0, 1.0]
If the implementation supports IEEE floating-point arithmetic (IEC 60559),

* If the argument is ±0, it is returned unmodified
* If |arg| > 1, a domain error occurs and NaN is returned.
* if the argument is NaN, NaN is returned

Example

// Run this code

  #include <cmath>
  #include <iostream>
  #include <cerrno>
  #include <cfenv>
  #include <cstring>

  #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';
  }

Possible output:

  asin(1.0) = 1.5708
  2*asin(1.0) = 3.14159
  asin(-0.5) = -0.523599
  6*asin(-0.5) = -3.14159
  asin(0.0) = 0 asin(-0.0)=-0
  asin(1.1) = nan
      errno == EDOM: Numerical argument out of domain
      FE_INVALID raised