frexp, frexpl

raw OCR

Splits a number into mantissa and exponent.

Defined in header <math.h>

Syntax

#include <math.h>
double frexp(double x, int *exponent);
long double frexpKlong  double x, int *exponent);

Portability

	DOS	UNIX	Windows	ANSI C	C++ only
frexp	■	■	■	■
frexpl	■		■

Remarks

frexp calculates the mantissa m (a double greater than or equal to 0.5 and less than 1) and the integer value n, such that x (the original double value) equals m x 2". frexp stores n in the integer that exponent points to. frexpl is the long double version; it takes a long double argument for x and returns a long double result.

Return value

frexp and frexpl return the mantissa m.

Error handling for these routines can be modified through the functions mattierr and _matherrl.

Example

#include <math.h>
#include <stdio.h>
int main(void)
{
   double mantissa, number = 8.0;
   int exponent;
   mantissa = frexp(number, *exponent);
   printfC'The number %lf is %lf times two to the power of %d\n", number,
           mantissa, exponent);
   return 0;

Differences from modern implementations

Nothing recorded yet.

Modern references

These are search links, not yet checked by hand.

Stable link: /3.1/math.h/frexp/ · short form /3.1/frexp/