acos(3) - f34

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

6       acos, acosf, acosl - arc cosine function
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SYNOPSIS

9       #include <math.h>
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11       double acos(double x);
12       float acosf(float x);
13       long double acosl(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       acosf(), acosl():
20           _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
21               || /* Since glibc 2.19: */ _DEFAULT_SOURCE
22               || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
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DESCRIPTION

25       These  functions calculate the arc cosine of x; that is the value whose
26       cosine is x.
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RETURN VALUE

29       On success, these functions return the arc cosine of x in radians;  the
30       return value is in the range [0, pi].
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32       If x is a NaN, a NaN is returned.
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34       If x is +1, +0 is returned.
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36       If  x is positive infinity or negative infinity, a domain error occurs,
37       and a NaN is returned.
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39       If x is outside the range [-1, 1], a domain error occurs, and a NaN  is
40       returned.
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ERRORS

43       See  math_error(7) for information on how to determine whether an error
44       has occurred when calling these functions.
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46       The following errors can occur:
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48       Domain error: x is outside the range [-1, 1]
49              errno is set  to  EDOM.   An  invalid  floating-point  exception
50              (FE_INVALID) is raised.
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ATTRIBUTES

53       For  an  explanation  of  the  terms  used  in  this  section,  see at‐
54       tributes(7).
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56       ┌─────────────────────────┬───────────────┬─────────┐
57       │Interface                │ Attribute     │ Value   │
58       ├─────────────────────────┼───────────────┼─────────┤
59       │acos(), acosf(), acosl() │ Thread safety │ MT-Safe │
60       └─────────────────────────┴───────────────┴─────────┘

CONFORMING TO

62       C99, POSIX.1-2001, POSIX.1-2008.
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64       The variant returning double also conforms to SVr4, 4.3BSD, C89.
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COLOPHON

70       This page is part of release 5.10 of the Linux  man-pages  project.   A
71       description  of  the project, information about reporting bugs, and the
72       latest    version    of    this    page,    can     be     found     at
73       https://www.kernel.org/doc/man-pages/.
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77                                  2017-09-15                           ACOS(3)