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 July 1, 2026 33.Dt MEMMOVE 9 34.Os 35.Sh NAME 36.Nm memmove , 37.Nm memmove_data 38.Nd copy bytes in memory 39.Sh SYNOPSIS 40.In sys/systm.h 41.Ft void * 42.Fn memmove "void *dst" "const void *src" "size_t len" 43.Ft void * 44.Fn memmove_data "void *dst" "const void *src" "size_t len" 45.Sh DESCRIPTION 46The 47.Fn memmove 48function copies 49.Fa len 50bytes from object 51.Fa src 52to object 53.Fa dst . 54The two objects may overlap; 55the copy is always done in a non-destructive manner and preserves 56the provenance of pointers in the copied object 57.Pq see Xr memory_model 7 for further information . 58The 59.Fn memmove_data 60function does the same except that it does not preserve the provenance 61of pointers in the copied object. 62On CHERI targets, the validity tag of any copied capability is 63explicitly cleared. 64.Sh RETURN VALUES 65The 66.Fn memmove 67and 68.Fn memmove_data 69functions return the original value of 70.Fa dst . 71.Sh SEE ALSO 72.Xr bcopy 9 , 73.Xr memcpy 9 , 74.Xr memcpy_data 9 75.Sh STANDARDS 76The 77.Fn memmove 78function 79conforms to 80.St -isoC . 81.Sh HISTORY 82The 83.Fn memmove_data 84function first appeared in 85.Fx 16.0 . 86