# `tanh`, `tanhf`, `tanhl`

Calculates the hyperbolic tangent.

## Syntax

``````double tanh( double x );
float tanhf( float x );
long double tanhl( long double x );
#define tanh(x) // Requires C11 or higher
``````
``````float tanh( float x );  // C++ only
long double tanh( long double x );  // C++ only
``````

`x`

## Return value

The `tanh` functions return the hyperbolic tangent of `x`. There's no error return.

Input SEH exception `_matherr` exception
± QNaN, IND none `_DOMAIN`

## Remarks

Because C++ allows overloading, you can call overloads of `tanh` that take and return `float` or `long double` values. In a C program, unless you're using the `<tgmath.h>` macro to call this function, `tanh` always takes and returns `double`.

If you use the `tanh` macro from `<tgmath.h>`, the type of the argument determines which version of the function is selected. See Type-generic math for details.

By default, this function's global state is scoped to the application. To change this behavior, see Global state in the CRT.

## Requirements

`tanh`, `tanhf`, `tanhl` `<math.h>` `<cmath>` or `<math.h>`
`tanh` macro `<tgmath.h>`

For more compatibility information, see Compatibility.

## Example

``````// crt_tanh.c
// This program displays the tangent of pi / 4
// and the hyperbolic tangent of the result.
// Compile by using: cl crt_tanh.c

#include <math.h>
#include <stdio.h>

int main( void )
{
double pi = 3.1415926535;
double x, y;

x = tan( pi / 4 );
y = tanh( x );
printf( "tan( %f ) = %f\n", pi/4, x );
printf( "tanh( %f ) = %f\n", x, y );
}
``````
``````tan( 0.785398 ) = 1.000000
tanh( 1.000000 ) = 0.761594
``````