cosh(3) - f39

1cosh(3)                    Library Functions Manual                    cosh(3)
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NAME

6       cosh, coshf, coshl - hyperbolic cosine function
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LIBRARY

9       Math library (libm, -lm)
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SYNOPSIS

12       #include <math.h>
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14       double cosh(double x);
15       float coshf(float x);
16       long double coshl(long double x);
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18   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
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20       coshf(), coshl():
21           _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
22               || /* Since glibc 2.19: */ _DEFAULT_SOURCE
23               || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
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DESCRIPTION

26       These  functions  return  the  hyperbolic cosine of x, which is defined
27       mathematically as:
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29           cosh(x) = (exp(x) + exp(-x)) / 2
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RETURN VALUE

32       On success, these functions return the hyperbolic cosine of x.
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34       If x is a NaN, a NaN is returned.
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36       If x is +0 or -0, 1 is returned.
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38       If x is positive infinity or negative infinity,  positive  infinity  is
39       returned.
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41       If the result overflows, a range error occurs, and the functions return
42       +HUGE_VAL, +HUGE_VALF, or +HUGE_VALL, respectively.
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ERRORS

45       See math_error(7) for information on how to determine whether an  error
46       has occurred when calling these functions.
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48       The following errors can occur:
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50       Range error: result overflow
51              errno  is  set  to ERANGE.  An overflow floating-point exception
52              (FE_OVERFLOW) is raised.
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ATTRIBUTES

55       For an  explanation  of  the  terms  used  in  this  section,  see  at‐
56       tributes(7).
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58       ┌────────────────────────────────────────────┬───────────────┬─────────┐
59       │Interface                                   │ Attribute     │ Value   │
60       ├────────────────────────────────────────────┼───────────────┼─────────┤
61       │cosh(), coshf(), coshl()                    │ Thread safety │ MT-Safe │
62       └────────────────────────────────────────────┴───────────────┴─────────┘
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STANDARDS

65       C11, POSIX.1-2008.
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HISTORY

68       C99, POSIX.1-2001.
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70       The variant returning double also conforms to SVr4, 4.3BSD.
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BUGS

73       In  glibc  2.3.4  and earlier, an overflow floating-point (FE_OVERFLOW)
74       exception is not raised when an overflow occurs.
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