1.\" $NetBSD: pow.3,v 1.1 2011/09/17 10:51:53 jruoho Exp $ 2.\" 3.\" Copyright (c) 2011 Jukka Ruohonen <jruohonen@iki.fi> 4.\" All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 15.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 16.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 17.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 18.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 19.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 20.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 21.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 22.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 23.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 24.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 25.\" POSSIBILITY OF SUCH DAMAGE. 26.\" 27.Dd September 13, 2011 28.Dt POW 3 29.Os 30.Sh NAME 31.Nm pow , 32.Nm powf 33.Nd power functions 34.Sh LIBRARY 35.Lb libm 36.Sh SYNOPSIS 37.In math.h 38.Ft double 39.Fn pow "double x" "double y" 40.Ft float 41.Fn powf "float x" "float y" 42.Sh DESCRIPTION 43The 44.Fn pow 45family of functions return 46.Fa x 47raised to the power of 48.Fa y . 49.Pp 50If 51.Fa x 52is negative and 53.Fa y 54is not an integer, the global variable 55.Va errno 56is set to 57.Er EDOM , 58and on 59.Tn VAX 60a reserved operand fault is generated. 61A portable application should nevertheless ensure that 62.Fa y 63is an integer value whenever 64.Fa x 65is negative. 66.Sh RETURN VALUES 67.\" 68.\" XXX: List also the special return values? 69.\" 70Upon successful completion, the described functions return 71.Fa x^y . 72.Sh SEE ALSO 73.Xr exp 3 , 74.Xr log 3 75.Sh STANDARDS 76The described functions conform to 77.St -isoC-99 . 78.Sh HISTORY 79The history of the power functions dates back to 80.At v6 . 81