asin - Man Page

Math library (libm, -lm)

#include <math.h>

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

asinf(), asinl():

    _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
        || /* Since glibc 2.19: */ _DEFAULT_SOURCE
        || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE

These functions calculate the principal value of the arc sine of x; that is the value whose sine is x.

On success, these functions return the principal value of the arc sine of x in radians; the return value is in the range [-pi/2, pi/2].

If x is a NaN, a NaN is returned.

If x is +0 (-0), +0 (-0) is returned.

If x is outside the range [-1, 1], a domain error occurs, and a NaN is returned.

See math_error(7) for information on how to determine whether an error has occurred when calling these functions.

The following errors can occur:

Domain error: x is outside the range [-1, 1]

errno is set to EDOM. An invalid floating-point exception (FE_INVALID) is raised.

For an explanation of the terms used in this section, see attributes(7).

C99, POSIX.1-2001, POSIX.1-2008.

The variant returning double also conforms to SVr4, 4.3BSD.

acos(3), atan(3), atan2(3), casin(3), cos(3), sin(3), tan(3)

acos(3), atan(3), atan2(3), cos(3), sin(3), tan(3).

The man pages asinf(3) and asinl(3) are aliases of asin(3).