1.\" Copyright (c) 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" This code is derived from software contributed to Berkeley by 5.\" the American National Standards Committee X3, on Information 6.\" Processing Systems. 7.\" 8.\" Redistribution and use in source and binary forms, with or without 9.\" modification, are permitted provided that the following conditions 10.\" are met: 11.\" 1. Redistributions of source code must retain the above copyright 12.\" notice, this list of conditions and the following disclaimer. 13.\" 2. Redistributions in binary form must reproduce the above copyright 14.\" notice, this list of conditions and the following disclaimer in the 15.\" documentation and/or other materials provided with the distribution. 16.\" 3. All advertising materials mentioning features or use of this software 17.\" must display the following acknowledgement: 18.\" This product includes software developed by the University of 19.\" California, Berkeley and its contributors. 20.\" 4. Neither the name of the University nor the names of its contributors 21.\" may be used to endorse or promote products derived from this software 22.\" without specific prior written permission. 23.\" 24.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34.\" SUCH DAMAGE. 35.\" 36.\" @(#)ldexp.3 8.2 (Berkeley) 4/19/94 37.\" $FreeBSD: src/lib/libc/gen/ldexp.3,v 1.5.2.3 2001/12/14 18:33:51 ru Exp $ 38.\" $DragonFly: src/lib/libc/gen/ldexp.3,v 1.2 2003/06/17 04:26:42 dillon Exp $ 39.\" 40.Dd April 19, 1994 41.Dt LDEXP 3 42.Os 43.Sh NAME 44.Nm ldexp 45.Nd multiply floating-point number by integral power of 2 46.Sh LIBRARY 47.Lb libc 48.Sh SYNOPSIS 49.In math.h 50.Ft double 51.Fn ldexp "double x" "int exp" 52.Sh DESCRIPTION 53The 54.Fn ldexp 55function multiplies a floating-point number by an integral 56power of 2. 57.Sh RETURN VALUES 58The 59.Fn ldexp 60function returns the value of 61.Fa x 62times 2 raised to the power 63.Fa exp . 64.Pp 65If the resultant value would cause an overflow, 66the global variable 67.Va errno 68is set to 69.Er ERANGE 70and the value 71.Dv HUGE 72is returned. 73.Sh SEE ALSO 74.Xr frexp 3 , 75.Xr math 3 , 76.Xr modf 3 77.Sh STANDARDS 78The 79.Fn ldexp 80function conforms to 81.St -isoC . 82