_fptan -- Calculate Tangent

Format

#include <builtin.h>
double _fptan(double x);

Language Level: Extension
_fptan calculates the tangent of x, where is x expressed in radians. The value of x must be less than 2**63. This function causes the compiler to emit the appropriate 80387 instruction for the calculation of tangent.

Because it is a built-in function and has no backing code in the library:

Return Value
_fptan returns the tangent of x expressed in radians.

Example
This example calculates the tangent of PI/4.

#include <builtin.h>
#include <stdio.h>
int main(void)
{
   double pi;
   pi = 3.1415926;
   printf("The tangent of %lf is %lf.\n", pi/4.0, _fptan(pi/4.0));
   return 0;
   /***************************************************************
      The output should be:
      The tangent of 0.785398 is 1.000000.
   ***************************************************************/
}



atan - atan2 -- Calculate Arctangent
_fpatan -- Calculate Arctangent
tan -- Calculate Tangent
tanh -- Calculate Hyperbolic Tangent
<builtin.h>