ultrix man page for modf

frexp(3)						     Library Functions Manual							  frexp(3)

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

Syntax
       #include <math.h>

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

       double ldexp(value, exp)
       double value;

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

Description
       The  subroutine returns the mantissa of a double value as a double quantity, x, of magnitude less than 1.0 and greater than or equal to 0.5
       (0.5 <= |x| < 1) and stores an integer n such that value = x*2**n indirectly through eptr.

       The returns the quantity value*2**exp.

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

Return Values
       If would cause overflow, +-HUGE_VAL is returned (according to the sign of value) and errno is set to ERANGE.  If would cause  underflow,  0
       is returned and errno is set to ERANGE.

																	  frexp(3)