asinf(3)

asinf3

Arc sine function

Part of asin(3).

Usage

#include <math.h>

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

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

Library

Math library (libm, -lm)

Overview

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).

InterfaceAttributeValue
asin(), asinf(), asinl()Thread safetyMT-Safe

Releases

12 releases since Debian 3.1 (Sarge); the text changed 11 times.

  1. 3.1
  2. 4.0
  3. 5.0
  4. 6.0
  5. 7
  6. 8
  7. 9
  8. 10
  9. 11
  10. 12
  11. 13
  12. Arch

Standards

C11, POSIX.1-2008.

History

C99, POSIX.1-2001.

The variant returning double also conforms to SVr4, 4.3BSD, C89.

From man-pages 6.19-1 in Arch Linux 2026-11-01. Parsed by carta from the page's man source.