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32  .\"     @(#)memcmp.3	8.1 (Berkeley) 6/4/93
33  .\" $FreeBSD$
34  .\"
35  .Dd June 4, 1993
36  .Dt MEMCMP 3
37  .Os
38  .Sh NAME
39  .Nm memcmp
40  .Nd compare byte string
41  .Sh LIBRARY
42  .Lb libc
43  .Sh SYNOPSIS
44  .In string.h
45  .Ft int
46  .Fo memcmp 
47  .Fa "const void *s1"
48  .Fa "const void *s2"
49  .Fa "size_t n"
50  .Fc
51  .Sh DESCRIPTION
52  The
53  .Fn memcmp
54  function
55  compares byte string
56  .Fa s1
57  against byte string
58  .Fa s2 .
59  Both strings are assumed to be
60  .Fa n
61  bytes long.
62  .Sh RETURN VALUES
63  The
64  .Fn memcmp
65  function
66  returns zero if the two strings are identical,
67  otherwise returns the difference between the first two differing bytes
68  (treated as
69  .Vt "unsigned char"
70  values, so that
71  .Sq Li \e200
72  is greater than
73  .Sq Li \&\e0 ,
74  for example).
75  Zero-length strings are always identical.
76  This behavior is not required by C and portable code should only depend on the
77  sign of the returned value.
78  .Sh SEE ALSO
79  .Xr bcmp 3 ,
80  .Xr strcasecmp 3 ,
81  .Xr strcmp 3 ,
82  .Xr strcoll 3 ,
83  .Xr strxfrm 3 ,
84  .Xr wmemcmp 3
85  .Sh STANDARDS
86  The
87  .Fn memcmp
88  function
89  conforms to
90  .St -isoC .