Upon successful completion, asin() returns the arc sine of x, in the range [-pi/2,pi/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.
|