# frexp(), frexpf()

Break a floating-point number into a normalized fraction and an integral power of 2

## Synopsis:

```#include <math.h>

double frexp( double value,
int* exp );

float frexpf( float value,
int* exp );
```

## Arguments:

value
The value you want to break into a normalized fraction.
exp
A pointer to a location where the function can store the integral power of 2.

## Library:

libm

Use the -l m option to qcc to link against this library.

## Description:

These functions break a floating-point number into a normalized fraction and an integral power of 2. It stores the integral power of 2 in the int pointed to by exp.

## Returns:

x, such that x is a double with magnitude in the interval [0.5, 1] or 0, and value equals x times 2 raised to the power exp. If value is 0, then both parts of the result are 0.

## Examples:

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

int main( void )
{
int expon;
double value;

value = frexp(  4.25, &expon );
printf( "%f %d\n", value, expon );
value = frexp( -4.25, &expon );
printf( "%f %d\n", value, expon );

return EXIT_SUCCESS;
}
```

produces the output:

```0.531250 3
-0.531250 3
```

## Classification:

Safety:
Cancellation point No
Interrupt handler No
Signal handler No