acosh(3p)

1ACOSH(3P)                  POSIX Programmer's Manual                 ACOSH(3P)
2
3
4

PROLOG

6       This  manual  page is part of the POSIX Programmer's Manual.  The Linux
7       implementation of this interface may differ (consult the  corresponding
8       Linux  manual page for details of Linux behavior), or the interface may
9       not be implemented on Linux.
10
11

NAME

13       acosh, acoshf, acoshl — inverse hyperbolic cosine functions
14

SYNOPSIS

16       #include <math.h>
17
18       double acosh(double x);
19       float acoshf(float x);
20       long double acoshl(long double x);
21

DESCRIPTION

23       The functionality described on this reference page is aligned with  the
24       ISO C  standard.  Any  conflict between the requirements described here
25       and the ISO C standard is unintentional. This  volume  of  POSIX.1‐2008
26       defers to the ISO C standard.
27
28       These  functions  shall  compute the inverse hyperbolic cosine of their
29       argument x.
30
31       An application wishing to check for error situations should  set  errno
32       to  zero  and  call  feclearexcept(FE_ALL_EXCEPT)  before calling these
33       functions. On return, if errno is non-zero or fetestexcept(FE_INVALID |
34       FE_DIVBYZERO  |  FE_OVERFLOW  | FE_UNDERFLOW) is non-zero, an error has
35       occurred.
36

RETURN VALUE

38       Upon successful completion, these functions shall  return  the  inverse
39       hyperbolic cosine of their argument.
40
41       For  finite  values  of x < 1, a domain error shall occur, and either a
42       NaN  (if  supported),  or  an  implementation-defined  value  shall  be
43       returned.
44
45       If x is NaN, a NaN shall be returned.
46
47       If x is +1, +0 shall be returned.
48
49       If x is +Inf, +Inf shall be returned.
50
51       If x is −Inf, a domain error shall occur, and a NaN shall be returned.
52

ERRORS

54       These functions shall fail if:
55
56       Domain Error
57                   The x argument is finite and less than +1.0, or is −Inf.
58
59                   If  the  integer expression (math_errhandling & MATH_ERRNO)
60                   is non-zero, then errno shall be set  to  [EDOM].   If  the
61                   integer  expression  (math_errhandling & MATH_ERREXCEPT) is
62                   non-zero, then the invalid floating-point  exception  shall
63                   be raised.
64
65       The following sections are informative.
66

EXAMPLES

68       None.
69

APPLICATION USAGE

71       On   error,   the   expressions  (math_errhandling  &  MATH_ERRNO)  and
72       (math_errhandling & MATH_ERREXCEPT) are independent of each other,  but
73       at least one of them must be non-zero.
74

RATIONALE

76       None.
77

FUTURE DIRECTIONS

79       None.
80

COPYRIGHT

88       Portions of this text are reprinted and reproduced in  electronic  form
89       from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
90       -- Portable Operating System Interface (POSIX),  The  Open  Group  Base
91       Specifications Issue 7, Copyright (C) 2013 by the Institute of Electri‐
92       cal and Electronics Engineers,  Inc  and  The  Open  Group.   (This  is
93       POSIX.1-2008  with  the  2013  Technical Corrigendum 1 applied.) In the
94       event of any discrepancy between this version and the original IEEE and
95       The  Open Group Standard, the original IEEE and The Open Group Standard
96       is the referee document. The original Standard can be  obtained  online
97       at http://www.unix.org/online.html .
98
99       Any  typographical  or  formatting  errors that appear in this page are
100       most likely to have been introduced during the conversion of the source
101       files  to  man page format. To report such errors, see https://www.ker‐
102       nel.org/doc/man-pages/reporting_bugs.html .
103
104
105
106IEEE/The Open Group                  2013                            ACOSH(3P)