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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 mathematically 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
      floating-point exception (FE_DIVBYZERO) is raised.








ATTRIBUTES

For an explanation of the terms used in this section, see attributes(7).


  

    Interface
    Attribute
    Value
  

  

    atanh (), atanhf (), atanhl ()
    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 5.04 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