asin-asinf-asinl.md

title	description	ms.date	api_name	api_location	api_type	topic_type	f1_keywords	helpviewer_keywords
asin, asinf, asinl	API reference for asin, asinf, and asinl; which calculate the arcsine of a floating-point value.	1/15/2021	asinf asinl asin _o_asin _o_asinf	msvcrt.dll msvcr80.dll msvcr90.dll msvcr100.dll msvcr100_clr0400.dll msvcr110.dll msvcr110_clr0400.dll msvcr120.dll msvcr120_clr0400.dll ucrtbase.dll api-ms-win-crt-math-l1-1-0.dll	DLLExport	apiref	asin asinl asinf	asin function asinl function asinf function trigonometric functions arcsine function

asin, asinf, asinl

Calculates the arcsine.

Syntax

double asin( double x );
float asinf ( float x );
long double asinl( long double x );
#define asin(X) // Requires C11 or higher

float asin( float x );  // C++ only
long double asin( long double x );  // C++ only

Parameters

x
Value whose arcsine is to be calculated.

Return value

The asin function returns the arcsine (the inverse sine function) of x in the range -π/2 to π/2 radians.

By default, if x is less than -1 or greater than 1, asin returns an indefinite.

Input	SEH exception	_matherr exception
± INF	INVALID	_DOMAIN
± QNaN, IND	none	_DOMAIN
`	x	> 1`

Remarks

Because C++ allows overloading, you can call overloads of asin with float and long double values. In a C program, unless you're using the <tgmath.h> macro to call this function, asin always takes and returns a double.

If you use the asin macro from <tgmath.h>, the type of the argument determines which version of the function is selected. See Type-generic math for details.

By default, this function's global state is scoped to the application. To change this behavior, see Global state in the CRT.

Requirements

Routine	Required header (C)	Required header (C++)
asin, asinf, asinl	<math.h>	<cmath> or <math.h>
asin macro	<tgmath.h>

Example

For more information, see acos, acosf, acosl.

See also

Math and floating-point support
acos, acosf, acosl
atan, atanf, atanl, atan2, atan2f, atan2l
cos, cosf, cosl
_matherr
sin, sinf, sinl
tan, tanf, tanl