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

NAME

acosh, acoshf, acoshl - inverse hyperbolic cosine function

SYNOPSIS

#include <math.h>

double acosh(double x);
float acoshf(float x);
long double acoshl(long double x);


Link with -lm.


  

  Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
  




acosh():


_ISOC99_SOURCE ||
  _POSIX_C_SOURCE >= 200112L
 || _XOPEN_SOURCE >= 500
 || /* Since glibc 2.19: */ _DEFAULT_SOURCE
 || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE



acoshf(), acoshl():

_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 cosine of x; that is the
  value whose hyperbolic cosine is x.





RETURN VALUE

On success, these functions return the inverse hyperbolic cosine of x.

If x is a NaN, a NaN is returned.


If x is +1, +0 is returned.


If x is positive infinity, positive infinity is
  returned.


If x is less than 1, a domain error occurs, and the
    functions return a NaN.






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 is less than 1

  
errno is set to EDOM. An invalid floating-point exception
      (FE_INVALID) is raised.








ATTRIBUTES

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


  

    Interface
    Attribute
    Value
  

  

    acosh (), acoshf (), acoshl ()
    Thread safety
    MT-Safe
  








CONFORMING TO

C99, POSIX.1-2001, POSIX.1-2008.

The variant returning double also conforms to SVr4,
  4.3BSD.






SEE ALSO

asinh(3), atanh(3), cacosh(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