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.\" from: @(#)cos.3 5.1 (Berkeley) 5/2/91
.\" $Id: frexp.3,v 1.3 2003/08/17 20:36:47 scp Exp $
.\"
.Dd January 30, 2003
.Dt FREXP 3
.Os
.Sh NAME
.Nm frexp
.Nd break floating-point number into normalized fraction and power of 2
.Sh SYNOPSIS
.Fd #include
.Ft double
.Fn frexp "double value" "int *exp"
.Ft float
.Fn frexpf "float value" "int *exp"
.Sh DESCRIPTION
The
.Fn frexp
and
.Fn frexpf
functions break the floating-point number
.Fa value
into a normalized fraction and an
integral power of 2. They store the integer in the int object pointed to by
.Fa exp.
.Pp
The functions return a number x such that x has a magnitude in the interval [1/2, 1) or 0, and
value = x*(2**exp).
.Sh SPECIAL VALUES
.Fn frexp "±0" "exp"
returns ±0, and stores 0 in the object pointed to by exp.
.Pp
.Fn frexp "±infinity" "exp"
returns ±infinity, and stores an unspecified value in the object pointed to by exp.
.Pp
.Fn frexp "Nan" "exp"
returns a Nan, and stores an unspecified value in the object pointed to by exp.
.Sh SEE ALSO
.Xr math 3 ,
.Xr scalbn
.Sh STANDARDS
The
.Fn frexp
and
.Fn frexpf
functions conform to ISO/IEC 9899:1999(E).