asin, asinf, asinl
From cppreference.com
Defined in header <math.h>
|
||
float asinf( float arg ); |
(1) | (since C99) |
double asin( double arg ); |
(2) | |
long double asinl( long double arg ); |
(3) | (since C99) |
_Decimal32 asind32( _Decimal32 arg ); |
(4) | (since C23) |
_Decimal64 asind64( _Decimal64 arg ); |
(5) | (since C23) |
_Decimal128 asind128( _Decimal128 arg ); |
(6) | (since C23) |
Defined in header <tgmath.h>
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||
#define asin( arg ) |
(7) | (since C99) |
1-6) Computes the principal values of the arc sine of arg.
7) Type-generic macro: If the argument has type long double, (3) (
asinl
) is called. Otherwise, if the argument has integer type or the type double, (2) (asin
) is called. Otherwise, (1) (asinf
) is called. If the argument is complex, then the macro invokes the corresponding complex function (casinf, casin, casinl).
The functions (4-6) are declared if and only if the implementation predefines |
(since C23) |
Parameters
arg | - | floating-point value |
Return value
If no errors occur, the arc sine of arg (arcsin(arg)) in the range [-π |
2 |
π |
2 |
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 <errno.h> #include <fenv.h> #include <math.h> #include <stdio.h> #include <string.h> #ifndef __GNUC__ #pragma STDC FENV_ACCESS ON #endif int main(void) { printf("asin( 1.0) = %+f, 2*asin( 1.0)=%+f\n", asin(1), 2 * asin(1)); printf("asin(-0.5) = %+f, 6*asin(-0.5)=%+f\n", asin(-0.5), 6 * asin(-0.5)); // special values printf("asin(0.0) = %1f, asin(-0.0)=%f\n", asin(+0.0), asin(-0.0)); // error handling errno = 0; feclearexcept(FE_ALL_EXCEPT); printf("asin(1.1) = %f\n", asin(1.1)); if (errno == EDOM) perror(" errno == EDOM"); if (fetestexcept(FE_INVALID)) puts(" FE_INVALID raised"); }
Possible output:
asin( 1.0) = +1.570796, 2*asin( 1.0)=+3.141593 asin(-0.5) = -0.523599, 6*asin(-0.5)=-3.141593 asin(0.0) = 0.000000, asin(-0.0)=-0.000000 asin(1.1) = nan errno == EDOM: Numerical argument out of domain FE_INVALID raised
References
- C23 standard (ISO/IEC 9899:2023):
- 7.12.4.2 The asin functions (p: TBD)
- 7.25 Type-generic math <tgmath.h> (p: TBD)
- F.10.1.2 The asin functions (p: TBD)
- C17 standard (ISO/IEC 9899:2018):
- 7.12.4.2 The asin functions (p: 174)
- 7.25 Type-generic math <tgmath.h> (p: 272-273)
- F.10.1.2 The asin functions (p: 378)
- C11 standard (ISO/IEC 9899:2011):
- 7.12.4.2 The asin functions (p: 238)
- 7.25 Type-generic math <tgmath.h> (p: 373-375)
- F.10.1.2 The asin functions (p: 518)
- C99 standard (ISO/IEC 9899:1999):
- 7.12.4.2 The asin functions (p: 219)
- 7.22 Type-generic math <tgmath.h> (p: 335-337)
- F.9.1.2 The asin functions (p: 456)
- C89/C90 standard (ISO/IEC 9899:1990):
- 4.5.2.2 The asin function
See also
(C99)(C99) |
computes arc cosine (arccos(x)) (function) |
(C99)(C99) |
computes arc tangent (arctan(x)) (function) |
(C99)(C99) |
computes arc tangent, using signs to determine quadrants (function) |
(C99)(C99) |
computes sine (sin(x)) (function) |
(C99)(C99)(C99) |
computes the complex arc sine (function) |