asin(3M)
NAME
asin − arc sine function
SYNOPSIS
cc [ flag ... ] file ... −lm [ library ... ]
#include <math.h>
double asin(double x);
DESCRIPTION
The asin() function computes the principal value of the arc sine of x. The value of x should be in the range [−1,1].
RETURN VALUES
Upon successful completion, asin() returns the arc sine of x, in the range [−π/2,π/2] radians. If the value of x is not in the range [−1,1] and is not ±Inf or NaN, either 0.0 or NaN is returned and errno is set to EDOM.
If x is NaN, NaN is returned.
If x is ±Inf, either 0.0 is returned and errno is set to EDOM or NaN is returned and errno may be set to EDOM.
For exceptional cases, matherr(3M) tabulates the values to be returned as dictated by Standards other than XPG4.
ERRORS
The asin() function will fail if:
EDOM The value x is not ±Inf or NaN and is not in the range [−1,1].
The asin() function may fail if:
EDOM The value of x is ±Inf.
USAGE
An application wishing to check for error situations should set errno to 0, then call asin(). If errno is non-zero on return, or the return value is NaN, an error has occurred.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
| MT-Level | MT-Safe |
SEE ALSO
isnan(3M), matherr(3M), sin(3M), attributes(5), standards(5)
SunOS 5.6 — Last change: 29 Dec 1996