sinpi, sinpif, sinpil, sinpid32, sinpid64, sinpid128

From cppreference.com
< c‎ | numeric‎ | math
 
 
 
Common mathematical functions
Types
(C99)(C99)    

(C99)(C99)    

Functions
Basic operations
(C99)
(C99)
(C99)
(C99)(C99)(C99)(C23)
Maximum/minimum operations
(C99)
(C23)    
Exponential functions
(C23)
(C99)
(C99)
(C23)
(C23)
(C99)
(C99)(C23)
(C23)
(C23)
Power functions
(C99)
(C23)
(C23)
(C99)
(C23)
(C23)
Trigonometric and hyperbolic functions
sinpi
(C23)
(C23)
(C23)
(C23)
(C23)
(C23)
(C23)
(C99)
(C99)
(C99)
Error and gamma functions
(C99)
(C99)
(C99)
(C99)
Nearest integer floating-point operations
(C99)(C99)(C99)
(C99)
(C99)(C99)(C99)
(C23)(C23)(C23)(C23)
Floating-point manipulation functions
(C99)(C99)
(C99)(C23)
(C99)
Narrowing operations
(C23)
(C23)
(C23)
(C23)
(C23)
(C23)
Quantum and quantum exponent functions
Decimal re-encoding functions
Total order and payload functions
Classification
(C99)
(C99)
(C99)
(C23)
Macro constants
Special floating-point values
(C99)(C23)
Arguments and return values
(C99)(C99)(C99)(C99)(C99)    
Error handling
(C99)    

 
Defined in header <math.h>
float       sinpif( float arg );
(1) (since C23)
double      sinpi( double arg );
(2) (since C23)
long double sinpil( long double arg );
(3) (since C23)
_Decimal32  sinpid32( _Decimal32 arg );
(4) (since C23)
_Decimal64  sinpid64( _Decimal64 arg );
(5) (since C23)
_Decimal128 sinpid128( _Decimal128 arg );
(6) (since C23)
Defined in header <tgmath.h>
#define sinpi( arg )
(7) (since C23)
1-6) Computes the sine of π·arg measured in radians, thus regarding arg as a measurement in half-revolutions.
7) Type-generic macro: calls the correct function based on the type of arg. If the argument has integer type, (2) is called.

The functions (4-6) are declared if and only if the implementation predefines __STDC_IEC_60559_DFP__ (i.e. the implementation supports decimal floating-point numbers).

(since C23)

Parameters

arg - floating-point value whose product with π represents an angle in radians

Return value

If no errors occur, the sine of π·arg (sin(π×arg)) in the range [-1, +1], 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.

Example

#include <errno.h>
#include <fenv.h>
#include <math.h>
#include <stdio.h>
 
#ifndef __GNUC__
#pragma STDC FENV_ACCESS ON
#endif
 
#if __STDC_VERSION__ < 202311L
// A naive implementation of a subset of sinpi family
double sinpi(double arg)
{
    return sin(arg * (double)3.1415926535897932384626433);
}
#endif
 
int main(void)
{
    const double pi = acos(-1);
 
    // typical usage
    printf("sinpi(1) = %f, sin(pi) = %f\n", sinpi(1), sin(pi));
    printf("sinpi(0.5) = %f, sin(pi/2) = %f\n", sinpi(0.5), sin(pi / 2));
    printf("sinpi(-0.75) = %f, sin(-3*pi/4) = %f\n", sinpi(-0.75), sin(-3 * pi / 4));
 
    // special values
    printf("sinpi(+0) = %f\n", sinpi(0.0));
    printf("sinpi(-0) = %f\n", sinpi(-0.0));
 
    // error handling
    feclearexcept(FE_ALL_EXCEPT);
    printf("sinpi(INFINITY) = %f\n", sinpi(INFINITY));
    if (fetestexcept(FE_INVALID))
        puts("    FE_INVALID raised");
}

Possible output:

sinpi(1) = 0.000000, sin(pi) = 0.000000
sinpi(0.5) = 1.000000, sin(pi/2) = 1.000000
sinpi(-0.75) = -0.707107, sin(-3*pi/4) = -0.707107
sinpi(+0) = 0.000000
sinpi(-0) = -0.000000
sinpi(INFINITY) = -nan
    FE_INVALID raised

References

  • C23 standard (ISO/IEC 9899:2024):
  • 7.12.4.13 The sinpi functions (p: 247-248)
  • 7.27 Type generic math <tgmath.h> (p: 387)

See also

(C99)(C99)
computes sine (sin(x))
(function)