string/FreeBSD/memcmp.3

   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 .\"     @(#)memcmp.3    8.1 (Berkeley) 6/4/93
  37 .\" $FreeBSD: src/lib/libc/string/memcmp.3,v 1.8 2001/10/01 16:09:00 ru Exp $
  38 .\"
  39 .Dd June 4, 1993
  40 .Dt MEMCMP 3
  41 .Os
  42 .Sh NAME
  43 .Nm memcmp
  44 .Nd compare byte string
  45 .Sh LIBRARY
  46 .Lb libc
  47 .Sh SYNOPSIS
  48 .In string.h
  49 .Ft int
  50 .Fn memcmp "const void *b1" "const void *b2" "size_t len"
  51 .Sh DESCRIPTION
  52 The
  53 .Fn memcmp
  54 function
  55 compares byte string
  56 .Fa b1
  57 against byte string
  58 .Fa b2 .
  59 Both strings are assumed to be
  60 .Fa len
  61 bytes long.
  62 .Sh RETURN VALUES
  63 The
  64 .Fn memcmp
  65 function
  66 returns zero if the two strings are identical,
  67 otherwise returns the difference between the first two differing bytes
  68 (treated as unsigned char values, so that
  69 .Sq Li \e200
  70 is greater than
  71 .Sq Li \&\e0 ,
  72 for example).
  73 Zero-length strings are always identical.
  74 .Sh SEE ALSO
  75 .Xr bcmp 3 ,
  76 .Xr strcasecmp 3 ,
  77 .Xr strcmp 3 ,
  78 .Xr strcoll 3 ,
  79 .Xr strxfrm 3
  80 .Sh STANDARDS
  81 The
  82 .Fn memcmp
  83 function
  84 conforms to
  85 .St -isoC .