ASIN(3) | Linux Programmer's Manual | ASIN(3) |

# NAME

asin, asinf, asinl - arc sine function# SYNOPSIS

#include <math.h>

double asin(doublex);float asinf(floatx);long double asinl(long doublex);

Link with *-lm*.

Feature Test Macro Requirements for glibc (see
feature_test_macros(7)):

**asinf**(), **asinl**():

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

# DESCRIPTION

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

*x*.

# RETURN VALUE

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.

# ERRORS

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.

# ATTRIBUTES

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

asin (), asinf (), asinl () | Thread safety | MT-Safe |

# CONFORMING TO

C99, POSIX.1-2001, POSIX.1-2008.The variant returning *double* also conforms to SVr4, 4.3BSD,
C89.

# SEE ALSO

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

This page is part of release 5.13 of the Linux*man-pages*project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.

2021-03-22 |