frexp.3m (2010 09)

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frexp(3M) frexp(3M)

NAME

frexp( ), frexpf( ), frexpl( ), frexpw( ), frexpq( ) - extract mantissa and exponent from ﬂoating-point number

SYNOPSIS

#include <math.h>

double frexp(double value, int *exp);

HP Integrity Server Only

float frexpf(float value, int *exp);

long double frexpl(long double value, int *exp);

extended frexpw(extended value, int *exp);

quad frexpq(quad value, int *exp);

DESCRIPTION

The frexp() function breaks a ﬂoating-point number into a normalized fraction and an integral power

of 2. It stores the integer exponent in the

int object pointed to by exp .

Integrity Server Only

frexpf() is a float version of frexp(); it takes a float ﬁrst argument and returns a

float

result.

frexpl() is a long double version of frexp(); it takes a long double ﬁrst argument and

returns a long double result.

frexpw() is an extended version of frexp(); it takes an extended ﬁrst argument and returns an

extended result. frexpq() is equivalent to frexpl() on HP-UX systems.

USAGE

To use (for Integrity servers)

frexpf(), compile either with the default -Ae option or with the

-Aa

option.

To use (for Integrity servers)

frexpl(), frexpw(),orfrexpq(), compile either with the default

-Ae

option or with the -Aa and -D_HPUX_SOURCE

options.

To use (for Integrity servers)

frexpw() or frexpq(), compile also with the -fpwidetypes option.

To use any of these functions, make sure your program includes

<math.h>, and link in the math library

by specifying -lm on the compiler or linker command line. For more information, see the HP-UX

ﬂoating-point guide for HP Integrity servers at the following site:

http://www.hp.com/go/fp

RETURN VALUE

The

frexp() function returns the value x, such that x is a double with magnitude in the interval [0.5,

1] or zero, and value equals x times 2 raised to the power *exp .

If value is zero, returns value and stores zero in the object pointed to by exp .

If value is NaN,

frexp() returns NaN, and the value of *exp is unspeciﬁed.

If value is ±INFINITY,

frexp() returns value , and the value of *exp is unspeciﬁed.

These functions raise no exceptions.

ERRORS

No errors are deﬁned.