tanh(3) - f39

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

6       tanh, tanhf, tanhl - hyperbolic tangent 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 tanh(double x);
15       float tanhf(float x);
16       long double tanhl(long double x);
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18   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
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20       tanhf(), tanhl():
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 tangent of x, which is defined
27       mathematically as:
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29           tanh(x) = sinh(x) / cosh(x)
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RETURN VALUE

32       On success, these functions return the hyperbolic tangent 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 (-0), +0 (-0) is returned.
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38       If x is positive infinity (negative infinity), +1 (-1) is returned.
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ERRORS

41       No errors occur.
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ATTRIBUTES

44       For an  explanation  of  the  terms  used  in  this  section,  see  at‐
45       tributes(7).
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47       ┌────────────────────────────────────────────┬───────────────┬─────────┐
48       │Interface                                   │ Attribute     │ Value   │
49       ├────────────────────────────────────────────┼───────────────┼─────────┤
50       │tanh(), tanhf(), tanhl()                    │ Thread safety │ MT-Safe │
51       └────────────────────────────────────────────┴───────────────┴─────────┘
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STANDARDS

54       C11, POSIX.1-2008.
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HISTORY

57       C99, POSIX.1-2001.
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59       The variant returning double also conforms to SVr4, 4.3BSD, C89.
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