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FREXP(3)                   Linux Programmer's Manual                  FREXP(3)



NAME
       frexp, frexpf, frexpl - convert floating-point number to fractional and
       integral components

SYNOPSIS
       #include <&lt;math.h>&gt;

       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 <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

SEE ALSO
       ldexp(3), modf(3)

COLOPHON
       This  page  is  part of release 3.05 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/.



                                  2002-07-27                          FREXP(3)