FREXP(3) Linux Programmers Manual FREXP(3)
NAME
frexp, frexpf, frexpl  convert floatingpoint number to fractional and
integral components
SYNOPSIS
#include
double frexp(double x, int *exp);
float frexpf(float x, int *exp);
long double frexpl(long double x, int *exp);
Link with lm.
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 (exclu
sive). If x is zero, then the normalized fraction is zero and zero is
stored in exp.
CONFORMING TO
SVr4, 4.3BSD, C89, C99. The float and long double variants are C99
requirements.
EXAMPLE
#include
#include
#include
#include
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
SEE ALSO
ldexp(3), modf(3)
COLOPHON
This page is part of release 3.05 of the Linux manpages project. A
description of the project, and information about reporting bugs, can
be found at http://www.kernel.org/doc/manpages/.
20020727 FREXP(3)
