Linux Programmer’s Manual
asin, asinf, asinl − arc sine function
double asin(double x);
float asinf(float x);
long double asinl(long double x);
Link with −lm.
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
asinf(), asinl(): _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600 || _ISOC99_SOURCE;
or cc -std=c99
The asin() function calculates 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
The following errors can occur:
Domain error: x is outside the range [−1, 1]
errno is set to EDOM. An inv alid floating-point exception (FE_INVALID) is raised.
C99, POSIX.1-2001. The variant returning double also conforms to SVr4, 4.3BSD, C89.
acos(3), atan(3), atan2(3), casin(3), cos(3), sin(3), tan(3)
This page is part of release 3.24 of the Linux man-pages project. A description of the project, and informa-
tion about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.