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.\" 34.Dd July 14, 2021 35.Dt MEMCPY 3 36.Os 37.Sh NAME 38.Nm memcpy 39.Nd copy byte string 40.Sh LIBRARY 41.Lb libc 42.Sh SYNOPSIS 43.In string.h 44.Ft void * 45.Fn memcpy "void *dst" "const void *src" "size_t len" 46.Ft void * 47.Fn mempcpy "void *dst" "const void *src" "size_t len" 48.Sh DESCRIPTION 49The 50.Fn memcpy 51and 52.Fn mempcpy 53functions 54copy 55.Fa len 56bytes from string 57.Fa src 58to string 59.Fa dst . 60If 61.Fa src 62and 63.Fa dst 64overlap, the results are not defined. 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 strcpy 3 , 80.Xr wmemcpy 3 81.Xr wmempcpy 3 82.Sh STANDARDS 83The 84.Fn memcpy 85function 86conforms to 87.St -isoC . 88