1ATANH(3)                   Linux Programmer's Manual                  ATANH(3)
2
3
4

NAME

6       atanh, atanhf, atanhl - inverse hyperbolic tangent function
7

SYNOPSIS

9       #include <math.h>
10
11       double atanh(double x);
12       float atanhf(float x);
13       long double atanhl(long double x);
14
15       Link with -lm.
16
17   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
18
19       atanh():
20           _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
21               || _XOPEN_SOURCE >= 500
22               || /* Since glibc 2.19: */ _DEFAULT_SOURCE
23               || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
24
25       atanhf(), atanhl():
26           _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
27               || /* Since glibc 2.19: */ _DEFAULT_SOURCE
28               || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
29

DESCRIPTION

31       These  functions calculate the inverse hyperbolic tangent of x; that is
32       the value whose hyperbolic tangent is x.
33

RETURN VALUE

35       On success, these functions return the inverse hyperbolic tangent of x.
36
37       If x is a NaN, a NaN is returned.
38
39       If x is +0 (-0), +0 (-0) is returned.
40
41       If x is +1 or -1,  a  pole  error  occurs,  and  the  functions  return
42       HUGE_VAL,  HUGE_VALF,  or  HUGE_VALL, respectively, with the mathemati‐
43       cally correct sign.
44
45       If the absolute value of x is greater than 1, a  domain  error  occurs,
46       and a NaN is returned.
47

ERRORS

49       See  math_error(7) for information on how to determine whether an error
50       has occurred when calling these functions.
51
52       The following errors can occur:
53
54       Domain error: x less than -1 or greater than +1
55              errno is set  to  EDOM.   An  invalid  floating-point  exception
56              (FE_INVALID) is raised.
57
58       Pole error: x is +1 or -1
59              errno  is set to ERANGE (but see BUGS).  A divide-by-zero float‐
60              ing-point exception (FE_DIVBYZERO) is raised.
61

ATTRIBUTES

63       For  an  explanation  of  the  terms  used   in   this   section,   see
64       attributes(7).
65
66       ┌─────────────────────────────┬───────────────┬─────────┐
67       │Interface                    │ Attribute     │ Value   │
68       ├─────────────────────────────┼───────────────┼─────────┤
69       │atanh(), atanhf(), atanhl()  │ Thread safety │ MT-Safe │
70       └─────────────────────────────┴───────────────┴─────────┘

CONFORMING TO

72       C99, POSIX.1-2001, POSIX.1-2008.
73
74       The variant returning double also conforms to SVr4, 4.3BSD.
75

BUGS

77       In  glibc  2.9  and  earlier, when a pole error occurs, errno as set to
78       EDOM instead of the POSIX-mandated ERANGE.  Since version  2.10,  glibc
79       does the right thing.
80

SEE ALSO

82       acosh(3), asinh(3), catanh(3), cosh(3), sinh(3), tanh(3)
83

COLOPHON

85       This  page  is  part of release 5.02 of the Linux man-pages project.  A
86       description of the project, information about reporting bugs,  and  the
87       latest     version     of     this    page,    can    be    found    at
88       https://www.kernel.org/doc/man-pages/.
89
90
91
92                                  2017-09-15                          ATANH(3)
Impressum