tanhl - hyperbolic tangent function

NAME LIBRARY SYNOPSIS DESCRIPTION RETURN VALUE ERRORS ATTRIBUTES STANDARDS HISTORY SEE ALSO

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).

STANDARDS

C11, POSIX.1-2008.

HISTORY

C99, POSIX.1-2001.

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