asin, asinl

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Header File

math.h

Category

Math Routines

Prototype

double asin(double x);
long double asinl(long double x);

Description

Calculates the arc sine.

asin of a real argument returns the arc sine of the input value.

asinl is the long double version; it takes a long double argument and returns a long double result.

Real arguments to asin and asinl must be in the range -1 to 1, or else asin and asinl return NAN and set the global variable errno to

EDOM Domain error

Return Value

asin and asinl of a real argument return a value in the range -pi/2 to pi/2. Error handling for these functions may be modified through the functions _matherr and _matherrl.

Example

#include <stdio.h>
#include <math.h>
int main(void)
{
   double result;
   double x = 0.5;
   result = asin(x);
   printf("The arc sin of %lf is %lf\n", x, result);
   return(0);
}

Portability

	POSIX	Win32	ANSI C	ANSI C++
asin	+	+	+	+
asinl		+	+	+