C Standard Library

C <math.h> - scalbln() Function

The C <math.h> scalbln() function returns the result of multiplying the significand (x) by FLT_RADIX raised to the power of the exponent (n). Mathematically, it can be expressed as:

scalbln(x,n) = x * FLT_RADIXn

On most platforms, FLT_RADIX is 2, which makes this function equivalent to ldexp().

scalbn() is similar to this function, except scalbn() takes int as second argument.


double scalbln  (double x, long int n);
float scalblnf (float x, long int n);
long double scalblnl (long double x, long int n);                         


x Specify the value representing the significand.
n Specify the value of the exponent.

Return Value

Returns x * FLT_RADIXn.


The example below shows the usage of scalbln() function.

#include <stdio.h>
#include <math.h>
int main (){
  double x, result;
  long int n;
  x = 0.9;
  n = 4;

  result = scalbn(x, n);

  printf("Significand: %f\n", x);
  printf("Exponent: %li\n", n);
  printf("Result: %f\n", result);
  return 0;

The output of the above code will be:

Significand: 0.900000
Exponent: 4
Result: 14.400000

❮ C <math.h> Library