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   │
       ├───────────────────────────────────────────────────────────────┼───────────────┼─────────┤
       │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.

SEE ALSO

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