1.\" Copyright (c) 1985, 1991 Regents of the University of California. 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)sqrt.3 6.4 (Berkeley) 5/6/91 33.\" 34.Dd May 6, 1991 35.Dt SQRT 3 36.Os 37.Sh NAME 38.Nm cbrt , 39.Nm sqrt 40.Nd cube root and square root functions 41.Sh SYNOPSIS 42.Fd #include <math.h> 43.Ft double 44.Fn cbrt "double x" 45.Ft double 46.Fn sqrt "double x" 47.Sh DESCRIPTION 48The 49.Fn cbrt 50function computes 51the cube root of 52.Ar x . 53.Pp 54The 55.Fn sqrt 56computes the 57non-negative square root of x. 58.Sh RETURN VALUES 59The 60.Fn cbrt 61function returns the requested cube root. 62The 63.Fn sqrt 64function returns the requested square root 65unless an error occurs. 66On the 67.Tn VAX 68or 69.Tn Tahoe 70processor an attempt to take the 71.Fn sqrt 72of negative 73.Fa x 74causes an error; in this event, 75the global variable 76.Va errno 77is set to 78.Dv EDOM 79and a reserved operand fault is generated. 80.Sh ERROR (due to Roundoff etc.) 81The 82.Fn cbrt 83function 84is accurate to within 0.7 85.Em ulps . 86.Pp 87The 88.Fn sqrt 89function on a 90.Tn VAX 91is accurate to within 0.501 92.Em ulps . 93Sqrt on a machine that conforms to 94.Tn IEEE 95754 is correctly rounded 96in accordance with the rounding mode in force; the error is less than 97half an 98.Em ulp 99in the default mode (round\-to\-nearest). 100An 101.Em ulp 102is one 103.Em U Ns nit 104in the 105.Em L Ns ast 106.Em P Ns lace 107carried. 108.Sh SEE ALSO 109.Xr math 3 , 110.Xr infnan 3 111.Sh STANDARDS 112The 113.Nm sqrt 114function conforms to 115.St -ansiC . 116.Sh HISTORY 117The 118.Nm cbrt 119function appeared in 120.Bx 4.3 . 121