| NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | ATTRIBUTES | CONFORMING TO | BUGS | SEE ALSO | COLOPHON |  | 
ATANH(3)                  Linux Programmer's Manual                 ATANH(3)
       atanh, atanhf, atanhl - inverse hyperbolic tangent function
       #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
       These functions calculate the inverse hyperbolic tangent of x; that
       is the value whose hyperbolic tangent is x.
       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.
       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
              floating-point exception (FE_DIVBYZERO) is raised.
       For an explanation of the terms used in this section, see
       attributes(7).
       ┌─────────────────────────────┬───────────────┬─────────┐
       │Interface                    │ Attribute     │ Value   │
       ├─────────────────────────────┼───────────────┼─────────┤
       │atanh(), atanhf(), atanhl()  │ Thread safety │ MT-Safe │
       └─────────────────────────────┴───────────────┴─────────┘
       C99, POSIX.1-2001, POSIX.1-2008.
       The variant returning double also conforms to SVr4, 4.3BSD.
       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.
       acosh(3), asinh(3), catanh(3), cosh(3), sinh(3), tanh(3)
       This page is part of release 4.15 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)
Pages that refer to this page: acosh(3), asinh(3), catanh(3), cosh(3), sinh(3), tanh(3)
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