1ACOSH(3)                   Linux Programmer's Manual                  ACOSH(3)
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NAME

6       acosh, acoshf, acoshl - inverse hyperbolic cosine function
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SYNOPSIS

9       #include <math.h>
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11       double acosh(double x);
12       float acoshf(float x);
13       long double acoshl(long double x);
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15       Link with -lm.
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17   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
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19       acosh():
20           _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
21               || _XOPEN_SOURCE >= 500
22               || /* Since glibc 2.19: */ _DEFAULT_SOURCE
23               || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
24       acoshf(), acoshl():
25           _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
26               || /* Since glibc 2.19: */ _DEFAULT_SOURCE
27               || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
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DESCRIPTION

30       These  functions  calculate the inverse hyperbolic cosine of x; that is
31       the value whose hyperbolic cosine is x.
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RETURN VALUE

34       On success, these functions return the inverse hyperbolic cosine of x.
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36       If x is a NaN, a NaN is returned.
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38       If x is +1, +0 is returned.
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40       If x is positive infinity, positive infinity is returned.
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42       If x is less than 1, a domain error occurs, and the functions return  a
43       NaN.
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ERRORS

46       See  math_error(7) for information on how to determine whether an error
47       has occurred when calling these functions.
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49       The following errors can occur:
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51       Domain error: x is less than 1
52              errno is set  to  EDOM.   An  invalid  floating-point  exception
53              (FE_INVALID) is raised.
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ATTRIBUTES

56       For   an   explanation   of   the  terms  used  in  this  section,  see
57       attributes(7).
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59       ┌─────────────────────────────┬───────────────┬─────────┐
60       │Interface                    │ Attribute     │ Value   │
61       ├─────────────────────────────┼───────────────┼─────────┤
62       │acosh(), acoshf(), acoshl()  │ Thread safety │ MT-Safe │
63       └─────────────────────────────┴───────────────┴─────────┘

CONFORMING TO

65       C99, POSIX.1-2001, POSIX.1-2008.
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67       The variant returning double also conforms to SVr4, 4.3BSD.
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SEE ALSO

70       asinh(3), atanh(3), cacosh(3), cosh(3), sinh(3), tanh(3)
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COLOPHON

73       This page is part of release 4.15 of the Linux  man-pages  project.   A
74       description  of  the project, information about reporting bugs, and the
75       latest    version    of    this    page,    can     be     found     at
76       https://www.kernel.org/doc/man-pages/.
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80                                  2017-09-15                          ACOSH(3)
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