log2()

Compute base-2 logarithms.

  #include <math.h>
  
  double log2(double x);
  
  float log2f(float x);
  
  long double log2l(long double x);    

x

The value being computed.

These functions computes the base-2 logarithm of x, denoted as loge(1.0 + x).

The value of x must be greater than 0. Use fpclassify() to check the validity of the result returned by log1p().

For small magnitude x, these functions are more accurate than log(x+1.0). The functions return base-2 logarithm of x.

This facility may not be available on configurations of the EWL that run on platforms that do not have floating-point math capabilities.

#include <math.h>

#include <stdio.h>

int main(void)

{

float u = 5.0;

printf("log2(%f) = %f\n", u, log2f(u));

return 0;

}

Output:

log2(5.000000) = 2.321928.