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freebsd/lib/libc/string/memcpy.3
Dima Dorfman b06e8b97a9 Suggest using memmove(3) if src and dst may overlap.
PR:		33298
Submitted by:	Tim J. Robbins <tim@robbins.dropbear.id.au>
2002-01-07 06:03:37 +00:00

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.\" Copyright (c) 1990, 1991, 1993
.\" The Regents of the University of California. All rights reserved.
.\"
.\" This code is derived from software contributed to Berkeley by
.\" Chris Torek and the American National Standards Committee X3,
.\" on Information Processing Systems.
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.\" @(#)memcpy.3 8.1 (Berkeley) 6/4/93
.\" $FreeBSD$
.\"
.Dd June 4, 1993
.Dt MEMCPY 3
.Os
.Sh NAME
.Nm memcpy
.Nd copy byte string
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In string.h
.Ft void *
.Fn memcpy "void *dst" "const void *src" "size_t len"
.Sh DESCRIPTION
The
.Fn memcpy
function
copies
.Fa len
bytes from string
.Fa src
to string
.Fa dst .
.Sh RETURN VALUES
The
.Fn memcpy
function
returns the original value of
.Fa dst .
.Sh SEE ALSO
.Xr bcopy 3 ,
.Xr memccpy 3 ,
.Xr memmove 3 ,
.Xr strcpy 3
.Sh STANDARDS
The
.Fn memcpy
function
conforms to
.St -isoC .
.Sh BUGS
In this implementation
.Fn memcpy
is implemented using
.Xr bcopy 3 ,
and therefore the strings may overlap.
On other systems, copying overlapping strings may produce surprises.
Programs intended to be portable should use
.Xr memmove 3
when
.Fa src
and
.Fa dst
may overlap.