std::sin, std::sinf, std::sinl

Defined in header <cmath>
float       sin ( float arg );
float       sinf( float arg );
(since C++11)
double      sin ( double arg );
long double sin ( long double arg );
long double sinl( long double arg );
(since C++11)
double      sin ( IntegralType arg );
(4) (since C++11)
1-3) Computes the sine of arg (measured in radians).
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).


arg - value representing angle in radians, of a floating-point or Integral type

Return value

If no errors occur, the sine of arg (sin(arg)) in the range [-1 ; +1], is returned.

The result may have little or no significance if the magnitude of arg is large.

(until C++11)

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.

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

  • if the argument is ±0, it is returned unmodified
  • if the argument is ±∞, NaN is returned and FE_INVALID is raised
  • if the argument is NaN, NaN is returned


The case where the argument is infinite is not specified to be a domain error in C (to which C++ defers), but it is defined as a domain error in POSIX.

POSIX also specifies that in case of underflow, arg is returned unmodified, and if that is not supported, an implementation-defined value no greater than DBL_MIN, FLT_MIN, and LDBL_MIN is returned.


#include <iostream>
#include <cmath>
#include <cerrno>
#include <cfenv>
const double pi = std::acos(-1);
int main()
    // typical usage
    std::cout << "sin(pi/6) = " << std::sin(pi/6) << '\n'
              << "sin(pi/2) = " << std::sin(pi/2) << '\n'
              << "sin(-3*pi/4) = " << std::sin(-3*pi/4) << '\n';
    // special values
    std::cout << "sin(+0) = " << std::sin(0.0) << '\n'
              << "sin(-0) = " << std::sin(-0.0) << '\n';
    // error handling 
    std::cout << "sin(INFINITY) = " << std::sin(INFINITY) << '\n';
    if (std::fetestexcept(FE_INVALID))
        std::cout << "    FE_INVALID raised\n";

Possible output:

sin(pi/6) = 0.5
sin(pi/2) = 1
sin(-3*pi/4) = -0.707107
sin(+0) = 0
sin(-0) = -0
sin(INFINITY) = -nan
    FE_INVALID raised

See also

computes cosine (cos(x))
computes tangent (tan(x))
computes arc sine (arcsin(x))
computes sine of a complex number (sin(z))
(function template)
applies the function std::sin to each element of valarray
(function template)

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