1.\" $OpenBSD: ldexp.3,v 1.6 2008/12/12 00:12:47 martynas Exp $ 2.\" 3.\" Copyright (c) 1991, 1993 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" This code is derived from software contributed to Berkeley by 7.\" the American National Standards Committee X3, on Information 8.\" Processing Systems. 9.\" 10.\" Redistribution and use in source and binary forms, with or without 11.\" modification, are permitted provided that the following conditions 12.\" are met: 13.\" 1. Redistributions of source code must retain the above copyright 14.\" notice, this list of conditions and the following disclaimer. 15.\" 2. Redistributions in binary form must reproduce the above copyright 16.\" notice, this list of conditions and the following disclaimer in the 17.\" documentation and/or other materials provided with the distribution. 18.\" 3. Neither the name of the University nor the names of its contributors 19.\" may be used to endorse or promote products derived from this software 20.\" without specific prior written permission. 21.\" 22.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32.\" SUCH DAMAGE. 33.\" 34.Dd $Mdocdate: December 12 2008 $ 35.Dt LDEXP 3 36.Os 37.Sh NAME 38.Nm ldexp , 39.Nm ldexpf , 40.Nm ldexpl 41.Nd multiply floating-point number by integral power of 2 42.Sh SYNOPSIS 43.Fd #include <math.h> 44.Ft double 45.Fn ldexp "double x" "int exp" 46.Ft float 47.Fn ldexpf "float x" "int exp" 48.Ft long double 49.Fn ldexpl "long double x" "int exp" 50.Sh DESCRIPTION 51The 52.Fn ldexp 53function multiplies a floating-point number by an integral 54power of 2. 55The 56.Fn ldexpf 57function is a single precision version of 58.Fn ldexp . 59The 60.Fn ldexpl 61function is an extended precision version of 62.Fn ldexp . 63.Sh RETURN VALUES 64The 65.Fn ldexp , 66.Fn ldexpf 67and 68.Fn ldexpl 69functions return the value of 70.Fa x 71times 2 raised to the power 72.Fa exp . 73.Pp 74If the resultant value would cause an overflow, 75the global variable 76.Va errno 77is set to 78.Er ERANGE 79and the value 80.Dv HUGE 81is returned. 82.Sh SEE ALSO 83.Xr frexp 3 , 84.Xr math 3 , 85.Xr modf 3 86.Sh STANDARDS 87The 88.Fn ldexp 89function conforms to 90.St -ansiC . 91