acos(3) - c7

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           _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600 ||
21           _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L;
22           or cc -std=c99
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DESCRIPTION

25       The acos() function calculates the arc cosine of x; that is  the  value
26       whose 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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CONFORMING TO

53       C99, POSIX.1-2001.  The variant returning double also conforms to SVr4,
54       4.3BSD, C89.
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COLOPHON

60       This  page  is  part of release 3.53 of the Linux man-pages project.  A
61       description of the project, and information about reporting  bugs,  can
62       be found at http://www.kernel.org/doc/man-pages/.
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66                                  2010-09-20                           ACOS(3)