50a717a67b
Add notes to each of these that specifically state that results are undefined if the strings overlap. In the case of memcpy, we document the overlapping behavior on FreeBSD (pre-existing). For str*, it is left unspecified, however, since the default (and x86) implementations do not handle overlapping strings properly. PR: 223653 Sponsored by: Netflix
94 lines
2.7 KiB
Groff
94 lines
2.7 KiB
Groff
.\" Copyright (c) 1990, 1991, 1993
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" This code is derived from software contributed to Berkeley by
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.\" Chris Torek and the American National Standards Committee X3,
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.\" on Information Processing Systems.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)memcpy.3 8.1 (Berkeley) 6/4/93
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.\" $FreeBSD$
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.\"
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.Dd June 4, 1993
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.Dt MEMCPY 3
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.Os
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.Sh NAME
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.Nm memcpy
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.Nd copy byte string
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.In string.h
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.Ft void *
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.Fn memcpy "void *dst" "const void *src" "size_t len"
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.Sh DESCRIPTION
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The
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.Fn memcpy
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function
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copies
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.Fa len
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bytes from string
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.Fa src
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to string
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.Fa dst .
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If
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.Fa src
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and
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.Fa dst
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overlap, the results are not defined.
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.Sh RETURN VALUES
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The
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.Fn memcpy
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function
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returns the original value of
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.Fa dst .
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.Sh SEE ALSO
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.Xr bcopy 3 ,
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.Xr memccpy 3 ,
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.Xr memmove 3 ,
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.Xr strcpy 3 ,
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.Xr wmemcpy 3
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.Sh STANDARDS
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The
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.Fn memcpy
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function
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conforms to
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.St -isoC .
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.Sh BUGS
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In this implementation
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.Fn memcpy
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is implemented using
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.Xr bcopy 3 ,
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and therefore the strings may overlap.
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On other systems, copying overlapping strings may produce surprises.
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Programs intended to be portable should use
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.Xr memmove 3
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when
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.Fa src
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and
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.Fa dst
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may overlap.
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