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():
           _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 500 ||
           _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED || _ISOC99_SOURCE ||
           _POSIX_C_SOURCE >= 200112L;
           or cc -std=c99
       acoshf(), acoshl():
           _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600 ||
           _ISOC99_SOURCE || _POSIX_C_SOURCE >= 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 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.
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)