sinpi, sinpif, sinpil, sinpid32, sinpid64, sinpid128
From cppreference.com
| Defined in header <math.h>
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float sinpif( float arg );
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(1) | (since C23) |
double sinpi( double arg );
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(2) | (since C23) |
long double sinpil( long double arg );
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(3) | (since C23) |
_Decimal32 sinpid32( _Decimal32 arg );
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(4) | (since C23) |
_Decimal64 sinpid64( _Decimal64 arg );
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(5) | (since C23) |
_Decimal128 sinpid128( _Decimal128 arg );
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(6) | (since C23) |
| Defined in header <tgmath.h>
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#define sinpi( arg )
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(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 |
(since C23) |
Parameters
| arg | - | floating-point value whose product with π represents an angle in radians
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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
Run this code
#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) |