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.\" from: @(#)memcpy.3 8.1 (Berkeley) 6/4/93 33.\" $NetBSD: memcpy.3,v 1.15 2023/08/13 04:20:07 wiz Exp $ 34.\" 35.Dd August 1, 2023 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 * restrict dst" "const void * restrict src" "size_t len" 47.Ft void * 48.Fn mempcpy "void * restrict dst" "const void * restrict src" "size_t len" 49.Sh DESCRIPTION 50The 51.Fn memcpy 52and 53.Fn mempcpy 54functions 55copy 56.Fa len 57bytes from string 58.Fa src 59to string 60.Fa dst . 61The arguments must not overlap -- behavior if the arguments overlap is 62undefined. 63To copy byte strings that overlap, use 64.Xr memmove 3 . 65.Sh RETURN VALUES 66The 67.Fn memcpy 68function 69returns the original value of 70.Fa dst . 71.Pp 72The 73.Fn mempcpy 74function returns a pointer to the byte after the last written byte. 75.Sh SEE ALSO 76.Xr bcopy 3 , 77.Xr memccpy 3 , 78.Xr memmove 3 , 79.Xr wmemcpy 3 , 80.Xr wmempcpy 3 81.Sh STANDARDS 82The 83.Fn memcpy 84function 85conforms to 86.St -isoC-99 . 87