log10
 flog10 

 NAME
  log    - return the log of the double quantity, base 10
  flog   - return the log of the float quantity, base 10

 SYNOPSIS
  #include <math.h>

  double a = log10(b);
  double b;

  float  c = flog10(d);
  float  d;

 FUNCTION
  Returns the log of the floating point quantity, base 10.

 EXAMPLE
  /*
   *  compile with the math library -lm
   */

  #include <math.h>
  #include <stdio.h>

  main()
  {
      {
      double a = log10(0.25);
      printf("log10 0.25 = %lfn", a);     /*  -0.6021 */
      }
      {                       /*  less accuracy   */
      float a = flog10(0.25);
      printf("log10 0.25 = %lfn", (double)a);
      }
      return(0);
  }

 INPUTS
  double b;   double floating point value
  float  d;   float  floating point value

 RESULTS
  double a;   result double floating point value
  float  c;   result float  floating point value