Name
frexp, frexpf, frexpl — convert floating-point number to fractional and integral components
Synopsis
#include <math.h>
double frexp( |
double | x, |
| int * | exp); |
float
frexpf( |
float | x, |
| int * | exp); |
long
double frexpl( |
long double | x, |
| int * | exp); |
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Note |
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Link with |
DESCRIPTION
The frexp() function is used
to split the number x
into a normalized fraction and an exponent which is stored in
exp.
RETURN VALUE
The frexp() function returns
the normalized fraction. If the argument x is not zero, the normalized
fraction is x times a
power of two, and its absolute value is always in the range
1/2 (inclusive) to 1 (exclusive). If x is zero, then the normalized
fraction is zero and zero is stored in exp.
EXAMPLE
#include <math.h>
#include <float.h>
#include <stdio.h>
#include <stdlib.h>
int
main(int argc, char *argv[])
{
double x, r;
int exp;
x = strtod(argv[1], NULL);
r = frexp(x, &exp);
printf("frexp(%g, &e) = %g: %g * %d^%d = %g\n",
x, r, r, FLT_RADIX, exp, x);
exit(EXIT_SUCCESS);
} /* main */
This program produces results such as the following:
$ ./a.out 2560 frexp(2560, &e) = 0.625: 0.625 * 2^12 = 2560 $ ./a.out −4 frexp(−4, &e) = −0.5: −0.5 * 2^3 = -4
COLOPHON
This page is part of release 2.79 of the Linux man-pages project. A
description of the project, and information about reporting
bugs, can be found at
http://www.kernel.org/doc/man-pages/.
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Copyright 1993 David Metcalfe (davidprism.demon.co.uk) Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies. Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one. Since the Linux kernel and libraries are constantly changing, this manual page may be incorrect or out-of-date. The author(s) assume no responsibility for errors or omissions, or for damages resulting from the use of the information contained herein. The author(s) may not have taken the same level of care in the production of this manual, which is licensed free of charge, as they might when working professionally. Formatted or processed versions of this manual, if unaccompanied by the source, must acknowledge the copyright and authors of this work. References consulted: Linux libc source code Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991) 386BSD man pages Modified 1993-07-24 by Rik Faith (faithcs.unc.edu) Modified 2002-07-27 by Walter Harms (walter.harmsinformatik.uni-oldenburg.de) |