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

NAME
       acosh, acoshf, acoshl - inverse hyperbolic cosine function

SYNOPSIS
       #include 

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

       Link with -lm.

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

       acosh():
           BSDSOURCE || SVIDSOURCE || XOPENSOURCE >= 500 ||
           XOPENSOURCE && XOPENSOURCEEXTENDED || ISOC99SOURCE ||
           POSIXCSOURCE >= 200112L;
           or cc -std=c99
       acoshf(), acoshl():
           BSDSOURCE || SVIDSOURCE || XOPENSOURCE >= 600 ||
           ISOC99SOURCE || POSIXCSOURCE >= 200112L;
           or cc -std=c99

DESCRIPTION
       The acosh() function calculates 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 matherror(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
              (FEINVALID) 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.  The variant returning double also conforms to SVr4,
       4.3BSD, C89.

SEE ALSO
       asinh(3), atanh(3), cacosh(3), cosh(3), sinh(3), tanh(3)

COLOPHON
       This page is part of release 3.53 of the Linux  man-pages  project.   A
       description  of  the project, and information about reporting bugs, can
       be found at http://www.kernel.org/doc/man-pages/.



                                  2010-09-20                          ACOSH(3)