atanh(3) - Linux manual page (original) (raw)
atanh(3) Library Functions Manual atanh(3)
NAME top
atanh, atanhf, atanhl - inverse hyperbolic tangent functionLIBRARY top
Math library (_libm_, _-lm_)SYNOPSIS top
**#include <math.h>**
**double atanh(double** _x_**);**
**float atanhf(float** _x_**);**
**long double atanhl(long double** _x_**);**Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
**atanh**():
_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
|| _XOPEN_SOURCE >= 500
|| /* Since glibc 2.19: */ _DEFAULT_SOURCE
|| /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
**atanhf**(), **atanhl**():
_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
|| /* Since glibc 2.19: */ _DEFAULT_SOURCE
|| /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCEDESCRIPTION top
These functions calculate the inverse hyperbolic tangent of _x_;
that is the value whose hyperbolic tangent is _x_.RETURN VALUE top
On success, these functions return the inverse hyperbolic tangent
of _x_.
If _x_ is a NaN, a NaN is returned.
If _x_ is +0 (-0), +0 (-0) is returned.
If _x_ is +1 or -1, a pole error occurs, and the functions return
**HUGE_VAL**, **HUGE_VALF**, or **HUGE_VALL**, respectively, with the
mathematically correct sign.
If the absolute value of _x_ is greater than 1, a domain error
occurs, and a NaN is returned.ERRORS top
See [math_error(7)](../man7/math%5Ferror.7.html) for information on how to determine whether an
error has occurred when calling these functions.
The following errors can occur:
Domain error: _x_ less than -1 or greater than +1
_[errno](../man3/errno.3.html)_ is set to **EDOM**. An invalid floating-point exception
(**FE_INVALID**) is raised.
Pole error: _x_ is +1 or -1
_[errno](../man3/errno.3.html)_ is set to **ERANGE** (but see BUGS). A divide-by-zero
floating-point exception (**FE_DIVBYZERO**) is raised.ATTRIBUTES top
For an explanation of the terms used in this section, see
[attributes(7)](../man7/attributes.7.html).
┌──────────────────────────────────────┬───────────────┬─────────┐
│ **Interface** │ **Attribute** │ **Value** │
├──────────────────────────────────────┼───────────────┼─────────┤
│ **atanh**(), **atanhf**(), **atanhl**() │ Thread safety │ MT-Safe │
└──────────────────────────────────────┴───────────────┴─────────┘STANDARDS top
C11, POSIX.1-2008.HISTORY top
C99, POSIX.1-2001.
The variant returning _double_ also conforms to SVr4, 4.3BSD.BUGS top
In glibc 2.9 and earlier, when a pole error occurs, _[errno](../man3/errno.3.html)_ is set
to **EDOM** instead of the POSIX-mandated **ERANGE**. Since glibc 2.10,
glibc does the right thing.SEE ALSO top
[acosh(3)](../man3/acosh.3.html), [asinh(3)](../man3/asinh.3.html), [catanh(3)](../man3/catanh.3.html), [cosh(3)](../man3/cosh.3.html), [sinh(3)](../man3/sinh.3.html), [tanh(3)](../man3/tanh.3.html)COLOPHON top
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man-pages@man7.orgLinux man-pages 6.10 2024-07-23 atanh(3)
Pages that refer to this page:acosh(3), asinh(3), catanh(3), cosh(3), sinh(3), tanh(3)