Format
#include <builtin.h> double _fpatan(double x);
Language Level: Extension
_fpatan calculates the arctangent of x,
which is a value in radians between -PI/2 and PI/2. This function
causes the compiler to emit the appropriate 80387 instruction for
the calculation of arctangent.
Because it is a built-in function and has no backing code in the library:
Return Value
This function returns the arctangent of x.
Example
This example calculates the arctangent of
x.
#include <builtin.h> #include <stdio.h>
int main(void)
{
double x;
x = 0.45;
printf("The arctangent of %lf is %lf.\n", x, _fpatan(x));
return 0;
/********************************************************
The output should be :
The arctangent of 0.450000 is 0.422854. ********************************************************/ }
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atan - atan2 -- Calculate
Arctangent
_fptan --
Calculate Tangent
tan -- Calculate
Tangent
tanh -- Calculate
Hyperbolic Tangent
<builtin.h>