freebsd-nq/lib/libc/string/memcmp.3

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.\"     @(#)memcmp.3	8.1 (Berkeley) 6/4/93
.\" $FreeBSD$
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.Dd August 15, 2016
.Dt MEMCMP 3
.Os
.Sh NAME
.Nm memcmp
.Nd compare byte string
.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 string
.Fa b1
against byte string
.Fa b2 .
Both strings are assumed to be
.Fa len
bytes long.
.Sh RETURN VALUES
The
.Fn memcmp
function
returns zero if the two strings are identical,
otherwise returns the difference between the first two differing bytes
(treated as
.Vt "unsigned char"
values, so that
.Sq Li \e200
is greater than
.Sq Li \&\e0 ,
for example).
Zero-length strings are always identical.
.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 .