tanh(3) Library Functions Manual tanh(3)

tanh, tanhf, tanhl - hyperbolic tangent function

Math library (libm, -lm)

#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

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


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

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.

No errors occur.

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

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

C99, POSIX.1-2001, POSIX.1-2008.

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

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

2022-12-15 Linux man-pages 6.02