asin, asinf, asinl - cppreference.com (original) (raw)

1-6) Computes the principal values of the arc sine of arg.

1. 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).

[edit] Parameters

[edit] Return value

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

[edit] 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.

[edit] Example

#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, 2asin( 1.0)=%+f\n", asin(1), 2 * asin(1)); printf("asin(-0.5) = %+f, 6asin(-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, 2asin( 1.0)=+3.141593 asin(-0.5) = -0.523599, 6asin(-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

[edit] References

• C23 standard (ISO/IEC 9899:2024):

• 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

[edit] See also