.\" Copyright (c) 1985, 1991 Regents of the University of California. .\" All rights reserved. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" 3. All advertising materials mentioning features or use of this software .\" must display the following acknowledgement: .\" This product includes software developed by the University of .\" California, Berkeley and its contributors. .\" 4. Neither the name of the University nor the names of its contributors .\" may be used to endorse or promote products derived from this software .\" without specific prior written permission. .\" .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE .\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" .\" from: @(#)sqrt.3 6.4 (Berkeley) 5/6/91 .\" $Id: sqrt.3,v 1.1.1.1 1994/08/19 09:39:42 jkh Exp $ .\" .Dd May 6, 1991 .Dt SQRT 3 .Os .Sh NAME .Nm cbrt , .Nm cbrtf , .Nm sqrt , .Nm sqrtf .Nd cube root and square root functions .Sh SYNOPSIS .Fd #include .Ft double .Fn cbrt "double x" .Ft float .Fn cbrtf "float x" .Ft double .Fn sqrt "double x" .Ft float .Fn sqrtf "float x" .Sh DESCRIPTION The .Fn cbrt and the .Fn cbrtf functions compute the cube root of .Ar x . .Pp The .Fn sqrt and the .Fn sqrtf functions compute the non-negative square root of x. .Sh RETURN VALUES The .Fn cbrt and the .Fn cbrtf functions return the requested cube root. The .Fn sqrt and the .Fn sqrtf functions return the requested square root unless an error occurs. On the .Tn VAX or .Tn Tahoe processor an attempt to take the .Fn sqrt of negative .Fa x causes an error; in this event, the global variable .Va errno is set to .Dv EDOM and a reserved operand fault is generated. .Sh ERROR (due to Roundoff etc.) The .Fn cbrt function is accurate to within 0.7 .Em ulps . .Pp The .Fn sqrt function on a .Tn VAX is accurate to within 0.501 .Em ulps . Sqrt on a machine that conforms to .Tn IEEE 754 is correctly rounded in accordance with the rounding mode in force; the error is less than half an .Em ulp in the default mode (round\-to\-nearest). An .Em ulp is one .Em U Ns nit in the .Em L Ns ast .Em P Ns lace carried. .Sh SEE ALSO .Xr math 3 , .Xr infnan 3 .Sh STANDARDS The .Nm sqrt function conforms to .St -ansiC . .Sh HISTORY The .Nm cbrt function appeared in .Bx 4.3 .