1  .\" Copyright (c) 1990, 1991, 1993
 2  .\"	The Regents of the University of California.  All rights reserved.
 3  .\"
 4  .\" Redistribution and use in source and binary forms, with or without
 5  .\" modification, are permitted provided that the following conditions
 6  .\" are met:
 7  .\" 1. Redistributions of source code must retain the above copyright
 8  .\"    notice, this list of conditions and the following disclaimer.
 9  .\" 2. Redistributions in binary form must reproduce the above copyright
10  .\"    notice, this list of conditions and the following disclaimer in the
11  .\"    documentation and/or other materials provided with the distribution.
12  .\" 4. Neither the name of the University nor the names of its contributors
13  .\"    may be used to endorse or promote products derived from this software
14  .\"    without specific prior written permission.
15  .\"
16  .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
17  .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  .\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
20  .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  .\" SUCH DAMAGE.
27  .\"
28  .\"     @(#)strdup.3	8.1 (Berkeley) 6/9/93
29  .\" $FreeBSD: src/lib/libc/string/strdup.3,v 1.15 2009/04/07 13:42:53 trasz Exp $
30  .\"
31  .Dd December 5, 2008
32  .Dt STRDUP 3
33  .Os
34  .Sh NAME
35  .Nm strdup ,
36  .Nm strndup
37  .Nd save a copy of a string
38  .Sh LIBRARY
39  .Lb libc
40  .Sh SYNOPSIS
41  .In string.h
42  .Ft char *
43  .Fo strdup
44  .Fa "const char *s1"
45  .Fc
46  .Ft char *
47  .Fo strndup
48  .Fa "const char *s1"
49  .Fa "size_t n"
50  .Fc
51  .Sh DESCRIPTION
52  The
53  .Fn strdup
54  function
55  allocates sufficient memory for a copy
56  of the string
57  .Fa s1 ,
58  does the copy, and returns a pointer to it.
59  The pointer may subsequently be used as an
60  argument to the function
61  .Xr free 3 .
62  .Pp
63  If insufficient memory is available, NULL is returned and
64  .Va errno
65  is set to
66  .Er ENOMEM .
67  .Pp
68  The
69  .Fn strndup
70  function copies at most
71  .Fa n
72  characters from the string
73  .Fa s1
74  always
75  .Dv NUL
76  terminating the copied string.
77  .Sh SEE ALSO
78  .Xr free 3 ,
79  .Xr malloc 3
80  .Sh HISTORY
81  The
82  .Fn strdup
83  function first appeared in
84  .Bx 4.4 .
85  The
86  .Fn strndup
87  function was added in
88  .Fx 7.2 .