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.Dd July 1, 2026
.Dt MEMMOVE 9
.Os
.Sh NAME
.Nm memmove ,
.Nm memmove_data
.Nd copy bytes in memory
.Sh SYNOPSIS
.In sys/systm.h
.Ft void *
.Fn memmove "void *dst" "const void *src" "size_t len"
.Ft void *
.Fn memmove_data "void *dst" "const void *src" "size_t len"
.Sh DESCRIPTION
The
.Fn memmove
function copies
.Fa len
bytes from object
.Fa src
to object
.Fa dst .
The two objects may overlap;
the copy is always done in a non-destructive manner and preserves
the provenance of pointers in the copied object
.Pq see Xr memory_model 7 for further information .
The
.Fn memmove_data
function does the same except that it does not preserve the provenance
of pointers in the copied object.
On CHERI targets, the validity tag of any copied capability is
explicitly cleared.
.Sh RETURN VALUES
The
.Fn memmove
and
.Fn memmove_data
functions return the original value of
.Fa dst .
.Sh SEE ALSO
.Xr bcopy 9 ,
.Xr memcpy 9 ,
.Xr memcpy_data 9
.Sh STANDARDS
The
.Fn memmove
function
conforms to
.St -isoC .
.Sh HISTORY
The
.Fn memmove_data
function first appeared in
.Fx 16.0 .