bsd man page for modf

FREXP(3)						     Library Functions Manual							  FREXP(3)

NAME
       frexp, ldexp, modf - split into mantissa and exponent

SYNOPSIS
       double frexp(value, eptr)
       double value;
       int *eptr;

       double ldexp(value, exp)
       double value;

       double modf(value, iptr)
       double value, *iptr;

DESCRIPTION
       Frexp  returns  the  mantissa of a double value as a double quantity, x, of magnitude less than 1 and stores an integer n such that value =
       x*2n indirectly through eptr.

       Ldexp returns the quantity value*2exp.

       Modf returns the positive fractional part of value and stores the integer part indirectly through iptr.

7th Edition							   May 15, 1985 							  FREXP(3)