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 frexp 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 ldexp returns the quantity value*2**exp. 

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

Return Values

If ldexp would cause overflow, ±HUGE_VAL is returned (according to the sign of value) and errno is set to ERANGE.  If ldexp would cause underflow, 0 is returned and errno is set to ERANGE.