1993-03-21 12:45:37 +03:00
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.\" Copyright (c) 1991 The Regents of the University of California.
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgement:
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.\" This product includes software developed by the University of
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.\" California, Berkeley and its contributors.
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.\" 4. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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1993-08-01 11:42:49 +04:00
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.\" from: @(#)realloc.3 5.1 (Berkeley) 5/2/91
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.\" $Id: realloc.3,v 1.2 1993/08/01 07:44:18 mycroft Exp $
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1993-03-21 12:45:37 +03:00
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.\"
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.Dd May 2, 1991
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.Dt REALLOC 3
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.Os
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.Sh NAME
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.Nm realloc
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.Nd reallocation of memory function
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.Sh SYNOPSIS
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.Fd #include <stdlib.h>
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.Ft void *
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.Fn realloc "void *ptr" "size_t size"
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.Sh DESCRIPTION
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The
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.Fn realloc
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function changes the size of the object pointed to by
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.Fa ptr
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to the size specified by
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.Fa size .
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The contents of the object are unchanged up to the lesser
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of the new and old sizes.
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If the new size is larger, the value of the newly allocated portion
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of the object is indeterminate.
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If
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.Fa ptr
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is a null pointer, the
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.Fn realloc
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function behaves like the
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.Xr malloc 3
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function for the specified size.
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Otherwise, if
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.Fa ptr
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does not match a pointer earlier returned by the
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.Xr calloc 3 ,
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.Xr malloc 3 ,
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or
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.Fn realloc
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function, or if the space has been deallocated
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by a call to the
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.Xr free
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or
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.Fn realloc
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function, unpredictable and usually detrimental
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behaviour will occur.
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If the space cannot be allocated, the object
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pointed to by
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.Fa ptr
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is unchanged.
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If
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.Fa size
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is zero and
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.Fa ptr
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is not a null pointer, the object it points to is freed.
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.Pp
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The
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.Fn realloc
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function returns either a null pointer or a pointer
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to the possibly moved allocated space.
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.Sh SEE ALSO
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.Xr alloca 3 ,
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.Xr calloc 3 ,
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.Xr free 3 ,
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.Xr malloc 3 ,
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.Sh STANDARDS
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The
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.Fn realloc
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function conforms to
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.St -ansiC .
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