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man:atanhl

ATANH(3) Linux Programmer's Manual ATANH(3)

NAME

`     atanh, atanhf, atanhl - inverse hyperbolic tangent function`

SYNOPSIS

`     #include <math.h>`
```     double atanh(double x);
float atanhf(float x);
long double atanhl(long double x);```
`     Link with -lm.`
` 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 versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE```
```     atanhf(), atanhl():
_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
|| /* Since glibc 2.19: */ _DEFAULT_SOURCE
|| /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE```

DESCRIPTION

```     These  functions calculate the inverse hyperbolic tangent of x; that is
the value whose hyperbolic tangent is x.```

RETURN VALUE

`     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  mathemati-
cally correct sign.```
```     If  the  absolute  value of x is greater than 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 less than -1 or greater than +1
errno  is  set  to  EDOM.   An  invalid floating-point exception
(FE_INVALID) is raised.```
```     Pole error: x is +1 or -1
errno is set to ERANGE (but see BUGS).  A divide-by-zero  float-
ing-point exception (FE_DIVBYZERO) is raised.```

ATTRIBUTES

```     For   an   explanation   of   the  terms  used  in  this  section,  see
attributes(7).```
```     allbox; lbw28 lb lb  l  l  l.   Interface Attribute Value  T{  atanh(),
atanhf(), atanhl() T}   Thread safety  MT-Safe```

CONFORMING TO

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

BUGS

```     In  glibc  2.9  and  earlier, when a pole error occurs, errno as set to
EDOM instead of the POSIX-mandated ERANGE.  Since version  2.10,  glibc
does the right thing.```

SEE ALSO

`     acosh(3), asinh(3), catanh(3), cosh(3), sinh(3), tanh(3)`

COLOPHON

```     This  page  is  part of release 4.16 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/.```
`                                2017-09-15                          ATANH(3)`
/data/webs/external/dokuwiki/data/pages/man/atanhl.txt · Last modified: 2019/05/17 09:47 by 127.0.0.1

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