tanh(3)

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
 | 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.

SEE ALSO
acosh(3), asinh(3), atanh(3), cosh(3), ctanh(3), sinh(3)