1.\" $NetBSD: ldexp.3,v 1.5 2016/03/17 18:29:59 nros 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.\" @(#)ldexp.3 8.2 (Berkeley) 4/19/94 35.\" 36.Dd March 17, 2016 37.Dt LDEXP 3 38.Os 39.Sh NAME 40.Nm ldexp , 41.Nm ldexpf , 42.Nm ldexpl 43.Nd multiply floating-point number by integral power of 2 44.Sh LIBRARY 45.Lb libm 46.Sh SYNOPSIS 47.In math.h 48.Ft double 49.Fn ldexp "double x" "int exp" 50.Ft float 51.Fn ldexpf "float x" "int exp" 52.Ft long double 53.Fn ldexpl "long double x" "int exp" 54.Sh DESCRIPTION 55The 56.Fn ldexp 57family of functions compute 58.Bd -ragged -offset indent 59.Va x 60* 612^\fIexp\fR 62.Ed 63.Pp 64for a real floating-point number 65.Fa x . 66.Sh RETURN VALUES 67The functions return the value of 68.Fa x 69times 2 raised to the power 70.Fa exp . 71Otherwise the following may occur: 72.Bl -enum -offset indent 73.It 74If 75.Fa x 76is \*(Na, a \*(Na is returned. 77.It 78If 79.Fa exp 80is zero or 81.Fa x 82is either \*(Pm 0 or \*(Pm\[if], 83.Fa x 84is returned. 85.It 86If the call would cause an overflow, a range error occurs and either 87.Dv \*(Pm\*HHUGE_VAL , 88.Dv \*(Pm\*HHUGE_VALF , 89or 90.Dv \*(Pm\*HHUGE_VALL 91is returned, depending on the sign of 92.Fa x 93and the type of the return value. 94.It 95If an underflow would be caused by the correct value, 96and the value is not representable, either 0.0 or 97an implementation-defined value is returned. 98.El 99.Sh SEE ALSO 100.Xr frexp 3 , 101.Xr math 3 , 102.Xr modf 3 103.Sh STANDARDS 104The described functions conform to 105.St -isoC-99 . 106