.\" Copyright (c) 1991 The Regents of the University of California. .\" All rights reserved. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" 3. All advertising materials mentioning features or use of this software .\" must display the following acknowledgement: .\" This product includes software developed by the University of .\" California, Berkeley and its contributors. .\" 4. Neither the name of the University nor the names of its contributors .\" may be used to endorse or promote products derived from this software .\" without specific prior written permission. .\" .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE .\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" .\" from: @(#)cos.3 5.1 (Berkeley) 5/2/91 .\" $Id: frexp.3,v 1.4 2004/12/20 21:35:45 scp Exp $ .\" .Dd December 11, 2006 .Dt FREXP 3 .Os .Sh NAME .Nm frexp .Nd break floating-point number into normalized fraction and power of 2 .Sh SYNOPSIS .Fd #include <math.h> .Ft double .Fn frexp "double value" "int *exp" .Ft long double .Fn frexpl "long double value" "int *exp" .Ft float .Fn frexpf "float value" "int *exp" .Sh DESCRIPTION The .Fn frexp 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 functions conform to ISO/IEC 9899:1999(E).