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. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)memcpy.3 8.1 (Berkeley) 6/4/93 33.\" $FreeBSD$ 34.\" 35.Dd June 4, 1993 36.Dt MEMCPY 3 37.Os 38.Sh NAME 39.Nm memcpy 40.Nd copy byte string 41.Sh LIBRARY 42.Lb libc 43.Sh SYNOPSIS 44.In string.h 45.Ft void * 46.Fn memcpy "void *dst" "const void *src" "size_t len" 47.Sh DESCRIPTION 48The 49.Fn memcpy 50function 51copies 52.Fa len 53bytes from string 54.Fa src 55to string 56.Fa dst . 57If 58.Fa src 59and 60.Fa dst 61overlap, the results are not defined. 62.Sh RETURN VALUES 63The 64.Fn memcpy 65function 66returns the original value of 67.Fa dst . 68.Sh SEE ALSO 69.Xr bcopy 3 , 70.Xr memccpy 3 , 71.Xr memmove 3 , 72.Xr strcpy 3 , 73.Xr wmemcpy 3 74.Sh STANDARDS 75The 76.Fn memcpy 77function 78conforms to 79.St -isoC . 80.Sh BUGS 81In this implementation 82.Fn memcpy 83is implemented using 84.Xr bcopy 3 , 85and therefore the strings may overlap. 86On other systems, copying overlapping strings may produce surprises. 87Programs intended to be portable should use 88.Xr memmove 3 89when 90.Fa src 91and 92.Fa dst 93may overlap. 94