# frexp(3) [ultrix man page]

```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)```

## Check Out this Related Man Page

```modf(3M)						  Mathematical Library Functions						  modf(3M)

NAME
modf, modff, modfl - decompose floating-point number

SYNOPSIS
c99 [ flag... ] file... -lm [ library... ]
#include <math.h>

double modf(double x, double *iptr);

float modff(float x, float *iptr);

long double modfl(long double x, long double *iptr);

DESCRIPTION
These  functions  break	the  argument x into integral and fractional parts, each of which has the same sign as the argument. It stores the
integral part as a double for the modf() function, a float for the modff() function, or a long double for themodfl() function in the object
pointed to by iptr.

RETURN VALUES
Upon successful completion, these functions return the signed fractional part of x.

If x is NaN, a NaN is returned and *iptr is set to NaN.

If x is +-Inf, +-0 is returned and *iptr is set to +-Inf.

ERRORS
No errors are defined.

USAGE
These functions compute the function result and *iptr such that:

a = modf(x, &iptr) ;
x == a+*iptr ;

ATTRIBUTES
See attributes(5) for descriptions of the following attributes:

+-----------------------------+-----------------------------+
|      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
+-----------------------------+-----------------------------+
|Interface Stability	     |Standard			   |
+-----------------------------+-----------------------------+
|MT-Level		     |MT-Safe			   |
+-----------------------------+-----------------------------+