Header File 

math.h  

Category 

Math Routines 

Prototype 

double tanh(double x); 

long double tanhl(long double x); 

Description 

Calculates the hyperbolic tangent. 

tanh computes the hyperbolic tangent, sinh(x)/cosh(x). 

tanhl is the long double version; it takes a long double argument and returns a long double result. Error handling for these functions can be modified through the functions _matherr and _matherrl. 

Return Value 

tanh and tanhl return the hyperbolic tangent of x. 

Example  

#include <stdio.h>
#include <math.h>
int main(void)
{
   double result, x;
   x = 0.5;
   result = tanh(x);
   printf("The hyperbolic tangent of %lf is %lf\n", x, result);
   return 0;
}

Portability