string/FreeBSD/swab.3

   1 .\" Copyright (c) 1990, 1991, 1993
   2 .\"     The Regents of the University of California.  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 .\" 4. Neither the name of the University nor the names of its contributors
  13 .\"    may be used to endorse or promote products derived from this software
  14 .\"    without specific prior written permission.
  15 .\"
  16 .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  17 .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18 .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19 .\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  20 .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21 .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  22 .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  23 .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  24 .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  25 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  26 .\" SUCH DAMAGE.
  27 .\"
  28 .\"     @(#)swab.3      8.1 (Berkeley) 6/4/93
  29 .\" $FreeBSD: src/lib/libc/string/swab.3,v 1.10 2007/01/09 00:28:12 imp Exp $
  30 .\"
  31 .Dd February 24, 2010
  32 .Dt SWAB 3
  33 .Os
  34 .Sh NAME
  35 .Nm swab
  36 .Nd swap adjacent bytes
  37 .Sh LIBRARY
  38 .Lb libc
  39 .Sh SYNOPSIS
  40 .In unistd.h
  41 .Ft void
  42 .Fo swab
  43 .Fa "const void *restrict src"
  44 .Fa "void *restrict dest"
  45 .Fa "ssize_t nbytes"
  46 .Fc
  47 .Sh DESCRIPTION
  48 The function
  49 .Fn swab
  50 copies
  51 .Fa nbytes
  52 bytes from the location referenced by
  53 .Fa src
  54 to the location referenced by
  55 .Fa dest ,
  56 swapping adjacent bytes.
  57 .Pp
  58 The argument
  59 .Fa nbytes
  60 should be an even number.  If
  61 .Fa nbytes
  62 is odd,
  63 .Fn swab
  64 copies and exchanges
  65 .Fa nbytes
  66 -1 bytes and the disposition of the last byte is unspecified.
  67 If copying takes place between objects that overlap,
  68 the behavior is undefined. If
  69 .Fa nbytes
  70 is negative,
  71 .Fn swab
  72 does nothing.
  73 .Sh SEE ALSO
  74 .Xr bzero 3 ,
  75 .Xr memset 3 ,
  76 .Xr compat 5
  77 .Sh HISTORY
  78 A
  79 .Fn swab
  80 function appeared in
  81 .At v7 .