1ACOSH(3) Linux Programmer's Manual ACOSH(3)
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6 acosh, acoshf, acoshl - inverse hyperbolic cosine function
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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(): _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 500 ||
20 _ISOC99_SOURCE; or cc -std=c99
21 acoshf(), acoshl(): _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600
22 || _ISOC99_SOURCE; or cc -std=c99
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25 The acosh() function calculates the inverse hyperbolic cosine of x;
26 that is the value whose hyperbolic cosine is x.
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29 On success, these functions return the inverse hyperbolic cosine of x.
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31 If x is a NaN, a NaN is returned.
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33 If x is +1, +0 is returned.
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35 If x is positive infinity, positive infinity is returned.
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37 If x is less than 1, a domain error occurs, and the functions return a
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41 See math_error(7) for information on how to determine whether an error
42 has occurred when calling these functions.
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44 The following errors can occur:
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46 Domain error: x is less than 1
47 errno is set to EDOM. An invalid floating-point exception
48 (FE_INVALID) is raised.
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51 C99, POSIX.1-2001. The variant returning double also conforms to SVr4,
52 4.3BSD, C89.
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55 asinh(3), atanh(3), cacosh(3), cosh(3), sinh(3), tanh(3)
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58 This page is part of release 3.22 of the Linux man-pages project. A
59 description of the project, and information about reporting bugs, can
60 be found at http://www.kernel.org/doc/man-pages/.
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64 2008-08-05 ACOSH(3)