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.\" Copyright (c) 1991 The Regents of the University of California.
.\" 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. All advertising materials mentioning features or use of this software
.\" must display the following acknowledgement:
.\" This product includes software developed by the University of
.\" California, Berkeley and its contributors.
.\" 4. Neither the name of the University nor the names of its contributors
.\" may be used to endorse or promote products derived from this software
.\" without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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.
.\"
.\" from: @(#)realloc.3 5.1 (Berkeley) 5/2/91
.\" $Id: realloc.3,v 1.1 1995/10/18 08:42:19 deraadt Exp $
.\"
.Dd May 2, 1991
.Dt REALLOC 3
.Os
.Sh NAME
.Nm realloc
.Nd reallocation of memory function
.Sh SYNOPSIS
.Fd #include <stdlib.h>
.Ft void *
.Fn realloc "void *ptr" "size_t size"
.Sh DESCRIPTION
The
.Fn realloc
function changes the size of the object pointed to by
.Fa ptr
to the size specified by
.Fa size .
The contents of the object are unchanged up to the lesser
of the new and old sizes.
If the new size is larger, the value of the newly allocated portion
of the object is indeterminate.
If
.Fa ptr
is a null pointer, the
.Fn realloc
function behaves like the
.Xr malloc 3
function for the specified size.
Otherwise, if
.Fa ptr
does not match a pointer earlier returned by the
.Xr calloc 3 ,
.Xr malloc 3 ,
or
.Fn realloc
function, or if the space has been deallocated
by a call to the
.Xr free
or
.Fn realloc
function, unpredictable and usually detrimental
behavior will occur.
If the space cannot be allocated, the object
pointed to by
.Fa ptr
is unchanged.
If
.Fa size
is zero and
.Fa ptr
is not a null pointer, the object it points to is freed.
.Pp
The
.Fn realloc
function returns either a null pointer or a pointer
to the possibly moved allocated space.
.Sh SEE ALSO
.Xr alloca 3 ,
.Xr calloc 3 ,
.Xr free 3 ,
.Xr malloc 3 ,
.Sh STANDARDS
The
.Fn realloc
function conforms to
.St -ansiC .
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