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.\" $OpenBSD: pw_dup.3,v 1.3 2002/07/18 19:09:19 millert Exp $
.\"
.\" Copyright (c) 2000 Todd C. Miller <Todd.Miller@courtesan.com>
.\" All rights reserved.
.\"
.\" 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. The name of the author may not be used to endorse or promote products
.\" derived from this software without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED ``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 AUTHOR 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 15, 2000
.Dt PW_DUP 3
.Os
.Sh NAME
.Nm pw_dup
.Nd make a copy of a struct passwd
.Sh SYNOPSIS
.Fd #include <pwd.h>
.Ft struct passwd *
.Fn pw_dup "const struct passwd *pw"
.Sh DESCRIPTION
The
.Fn pw_dup
function allocates sufficient memory for a copy of the struct passwd
.Fa pw ,
does the copy, and returns a pointer to it.
This is useful as subsequent calls to
.Fn getpwent ,
.Fn getpwnam ,
and
.Fn getpwuid
will overwrite the data from previous calls.
.Pp
The returned pointer may be deallocated by a single call to
.Xr free 3 .
Since
.Fn pw_dup
allocates space for the copy in one chunk it is not necessary to free
the individual strings contained in the returned struct passwd.
.Pp
If insufficient memory is available,
.Dv NULL
is returned.
.Sh EXAMPLES
The following will make a copy of the struct passwd for root and
store it in
.Qq pw_save :
.Bd -literal -offset indent
struct passwd *pw, *pw_save;
if ((pw = getpwnam("root")) == NULL) {
fprintf(stderr, "Cannot find root in the password file.\en");
exit(1);
}
if ((pw_save = pw_dup(pw)) == NULL) {
fprintf(stderr, "Out of memory.\en");
exit(1);
}
.Ed
.Sh ERRORS
.Fn pw_dup
function may fail and set the external variable
.Va errno
for any of the errors specified for the library function
.Xr malloc 3 .
.Sh SEE ALSO
.Xr free 3 ,
.Xr getpwent 3 ,
.Xr malloc 3
.Sh HISTORY
The
.Fn pw_dup
function first appeared in
.Ox 2.9 .
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