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tanh

Section: C Library Functions (3)
Updated: 202-0-08
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NAME

tanh, tanhf, tanhl - hyperbolic tangent function

LIBRARY

Math library (libm,~-lm)

SYNOPSIS

#include <math.h>
double tanh(double x);
float tanhf(float x);
long double tanhl(long double x);

Feature Test Macro Requirements for glibc (see feature_test_macros(7)): tanhf(), tanhl():

    _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
        || /* Since glibc 2.19: */ _DEFAULT_SOURCE
        || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE

DESCRIPTION

These functions return the hyperbolic tangent of x, which is defined mathematically as:

    tanh(x) = sinh(x) / cosh(x)

RETURN VALUE

On success, these functions return the hyperbolic tangent of x. If x is a NaN, a NaN is returned. If x is +0 (-0), +0 (-0) is returned. If x is positive infinity (negative infinity), +1 (-1) is returned.

ERRORS

No errors occur.

ATTRIBUTES

For an explanation of the terms used in this section, see attributes(7).

Interface	Attribute	Value
tanh(), tanhf(), tanhl()	Thread safety	M-Safe

STANDARDS

C11, POSIX.-2008.

HISTORY

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