tanh, tanhf, tanhl — hyperbolic tangent function


#include <math.h>

double tanh(double x);
float tanhf(float x);
long double tanhl(long double x);

Link with -lm.

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

tanhf(), tanhl():

   || /* Since glibc 2.19: */ _DEFAULT_SOURCE
   || /* Glibc versions <= 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)

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.


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

Conforming to

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

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)


This page is part of release 5.04 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.

Referenced By

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

The man pages tanhf(3) and tanhl(3) are aliases of tanh(3).

2017-09-15 Linux Programmer's Manual