crypt(3) - Switch SHA256/512 to the Linux implementation
[dragonfly.git] / lib / libc / string / memcpy.3
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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.
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16.\" 4. 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
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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.\" @(#)memcpy.3 8.1 (Berkeley) 6/4/93
716024cd 33.\" $FreeBSD: src/lib/libc/string/memcpy.3,v 1.8 2007/01/09 00:28:12 imp Exp $
1de703da 34.\" $DragonFly: src/lib/libc/string/memcpy.3,v 1.2 2003/06/17 04:26:46 dillon Exp $
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35.\"
36.Dd June 4, 1993
37.Dt MEMCPY 3
38.Os
39.Sh NAME
40.Nm memcpy
41.Nd copy byte string
42.Sh LIBRARY
43.Lb libc
44.Sh SYNOPSIS
45.In string.h
46.Ft void *
47.Fn memcpy "void *dst" "const void *src" "size_t len"
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48.Ft void *
49.Fn mempcpy "void *dst" "const void *src" "size_t len"
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50.Sh DESCRIPTION
51The
52.Fn memcpy
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53and
54.Fn mempcpy
55functions
56copy
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57.Fa len
58bytes from string
59.Fa src
60to string
61.Fa dst .
62.Sh RETURN VALUES
63The
64.Fn memcpy
65function
66returns the original value of
67.Fa dst .
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68The
69.Fn mempcpy
70function
71returns a pointer to the byte directly following the last byte written in
72.Fa dst .
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73.Sh SEE ALSO
74.Xr bcopy 3 ,
75.Xr memccpy 3 ,
76.Xr memmove 3 ,
77.Xr strcpy 3
78.Sh STANDARDS
79The
80.Fn memcpy
81function
82conforms to
83.St -isoC .
84.Sh BUGS
85In this implementation
86.Fn memcpy
87is implemented using
88.Xr bcopy 3 ,
89and therefore the strings may overlap.
90On other systems, copying overlapping strings may produce surprises.
91Programs intended to be portable should use
92.Xr memmove 3
93when
94.Fa src
95and
96.Fa dst
97may overlap.