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+.\" Copyright (c) 1990, 1991, 1993
+.\"	The Regents of the University of California.  All rights reserved.
+.\"
+.\" This code is derived from software contributed to Berkeley by
+.\" Chris Torek and the American National Standards Committee X3,
+.\" on Information Processing Systems.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\" 3. Neither the name of the University nor the names of its contributors
+.\"    may be used to endorse or promote products derived from this software
+.\"    without specific prior written permission.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+.\" SUCH DAMAGE.
+.\"
+.Dd November 20, 2024
+.Dt MEMCMP 3
+.Os
+.Sh NAME
+.Nm memcmp
+.Nd compare bytes in memory
+.Sh LIBRARY
+.Lb libc
+.Sh SYNOPSIS
+.In string.h
+.Ft int
+.Fn memcmp "const void *b1" "const void *b2" "size_t len"
+.Sh DESCRIPTION
+The
+.Fn memcmp
+function
+compares byte object
+.Fa b1
+against byte object
+.Fa b2 .
+Both objects are assumed to be
+.Fa len
+bytes long.
+.Sh RETURN VALUES
+The
+.Fn memcmp
+function returns zero if the two objects are identical.
+Zero-length objects are considered identical.
+The
+.Fn memcmp
+function returns a negative value if the first differing byte has a lower
+value in
+.Fa b1
+and a positive value if the first differing byte has a higher value in
+.Fa b1 .
+.Sh SEE ALSO
+.Xr bcmp 3 ,
+.Xr strcasecmp 3 ,
+.Xr strcmp 3 ,
+.Xr strcoll 3 ,
+.Xr strxfrm 3 ,
+.Xr timingsafe_memcmp 3 ,
+.Xr wmemcmp 3
+.Sh STANDARDS
+The
+.Fn memcmp
+function
+conforms to
+.St -isoC .
+.Sh CAVEATS
+If the objects differ, the C library
+.Fn memcmp
+implementation returns the difference between the first two differing bytes
+.Po treated as
+.Vt "unsigned char"
+values
+.Pc .
+This behavior is not specified by
+.St -isoC ,
+is not portable, and may not occur in light of compiler optimizations.