tanh

(3)

hyperbolic tangent function

Library functionsmanpages-dev 6.9.1-1also documents tanhf, tanhl

#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

LIBRARY

Math library (libm, -lm)

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	MT-Safe

STANDARDS

C11, POSIX.1-2008.

HISTORY

C99, POSIX.1-2001.

The variant returning double also conforms to SVr4, 4.3BSD, C89.