1.\" Copyright (c) 1990, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" This code is derived from software contributed to Berkeley by 5.\" Chris Torek and the American National Standards Committee X3, 6.\" on Information Processing Systems. 7.\" 8.\" Redistribution and use in source and binary forms, with or without 9.\" modification, are permitted provided that the following conditions 10.\" are met: 11.\" 1. Redistributions of source code must retain the above copyright 12.\" notice, this list of conditions and the following disclaimer. 13.\" 2. Redistributions in binary form must reproduce the above copyright 14.\" notice, this list of conditions and the following disclaimer in the 15.\" documentation and/or other materials provided with the distribution. 16.\" 3. All advertising materials mentioning features or use of this software 17.\" must display the following acknowledgement: 18.\" This product includes software developed by the University of 19.\" California, Berkeley and its contributors. 20.\" 4. Neither the name of the University nor the names of its contributors 21.\" may be used to endorse or promote products derived from this software 22.\" without specific prior written permission. 23.\" 24.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34.\" SUCH DAMAGE. 35.\" 36.\" from: @(#)memcmp.3 8.1 (Berkeley) 6/4/93 37.\" $NetBSD: memcmp.9,v 1.3 2002/02/13 08:18:45 ross Exp $ 38.\" 39.Dd July 7, 2001 40.Dt MEMCMP 9 41.Os 42.Sh NAME 43.Nm memcmp 44.Nd compare byte string 45.Sh SYNOPSIS 46.Fd #include \*[Lt]sys/systm.h\*[Gt] 47.Ft int 48.Fn memcmp "const void *b1" "const void *b2" "size_t len" 49.Sh DESCRIPTION 50The 51.Fn memcmp 52function 53compares byte string 54.Fa b1 55against byte string 56.Fa b2 . 57Both strings are assumed to be 58.Fa len 59bytes long. 60.Sh RETURN VALUES 61The 62.Fn memcmp 63function 64returns zero if the two strings are identical, 65otherwise returns the difference between the first two differing bytes 66(treated as unsigned char values, so that 67.Sq Li \e200 68is greater than 69.Sq Li \&\e0 , 70for example). 71Zero-length strings are always identical. 72.\" .Sh SEE ALSO 73.Sh STANDARDS 74The 75.Fn memcmp 76function 77conforms to 78.St -ansiC . 79