huschi.net

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 4.15 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                          ACOSH(3)