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.Dd November 18, 2023 33.Dt MEMCPY 3 34.Os 35.Sh NAME 36.Nm memcpy 37.Nd copy byte string 38.Sh LIBRARY 39.Lb libc 40.Sh SYNOPSIS 41.In string.h 42.Ft void * 43.Fn memcpy "void *dst" "const void *src" "size_t len" 44.Ft void * 45.Fn mempcpy "void *dst" "const void *src" "size_t len" 46.Sh DESCRIPTION 47The 48.Fn memcpy 49and 50.Fn mempcpy 51functions 52copy 53.Fa len 54bytes from string 55.Fa src 56to string 57.Fa dst . 58If 59.Fa src 60and 61.Fa dst 62overlap, the results are not defined. 63.Sh RETURN VALUES 64The 65.Fn memcpy 66function 67returns the original value of 68.Fa dst . 69.Pp 70The 71.Fn mempcpy 72function returns a pointer to the byte after the last written byte. 73.Sh SEE ALSO 74.Xr bcopy 3 , 75.Xr memccpy 3 , 76.Xr memmove 3 , 77.Xr strcpy 3 , 78.Xr wmemcpy 3 , 79.Xr wmempcpy 3 80.Sh STANDARDS 81The 82.Fn memcpy 83function 84conforms to 85.St -isoC . 86.Sh HISTORY 87The 88.Fn memcpy 89function first appeared in 90.At V 91and was reimplemented for 92.Bx 4.3 Tahoe . 93The 94.Fn mempcpy 95function first appeared in 96.Fx 13.1 . 97